How it Works
Carrier
Loading...
FV4ANB

Carrier FB4ASF, FC4BNB, FC4BNF, FD3ANA, FA4ANF Service Manual

...
Download
Page 1
Visit www.carrier.com
Service Manual
TABLE OF CONTENTS
Page
SAFETY CONSIDERATIONS...................................................2
INTRODUCTION........................................................................2
UNIT IDENTIFICATION...........................................................2
PRODUCT OFFERING..............................................................4
FAN MOTOR SPEED TAPS .....................................................4
FA4A, FB4A, FC4B, FF1D, FH4A, AND FX4A CIRCUIT BOARD FUNCTIONAND TROUBLESHOOTING
— CES013003-00 and -01 PCB...............................................2-7
• Unit Functions ............................................................................2
• Troubleshooting PCB..................................................................4
CIRCUIT BOARD FUNCTIONAND TROUBLESHOOTING
— HK61GA001 and HK61GA003 PCB .........................6-19
• PCB Component Functions.........................................................7
• Troubleshooting PCB................................................................11
ELECTRIC HEATER FUNCTION
AND TROUBLESHOOTING..............................................18
• Troubleshooting KFA, KFB, KFC, and KFD Series
Electric Heaters.......................................................................20
FAN COIL DESCRIPTION AND
TROUBLESHOOTING — FK4B .................................20-27
• Integrated Controls and Motor (ICM2)....................................20
• PCB Layout and Description....................................................20
• Sequence of Operation..............................................................21
• Easy Select Configuration Taps................................................22
• Troubleshooting PCB................................................................25
• Troubleshooting ICM2..............................................................25
• Condensed Version of Troubleshooting FK4B Motor
and Controls ...............................................................................27
• Accessories ................................................................................27
FAN COIL DESCRIPTION AND
TROUBLESHOOTING — FK4C, FV4A, 40FKA.........28-35
• Integrated Controls and Motor (ICM2)..................................28
• PCB Layout and Description..................................................29
• Sequence of Operation............................................................29
• Easy Select Configuration Taps..............................................32
• Troubleshooting PCB..............................................................33
• Troubleshooting ICM2............................................................33
• Condensed Version of Troubleshooting
FK4C, FV4A, 40FKA Motor and Controls.........................33
• Accessories ..............................................................................35
THERMOSTATIC EXPANSION VALVES (TXV)............36
• Problems Affecting TXV........................................................36
PISTON BODY CLEANING OR REPLACEMENT..........36
LIQUID TUBE STRAINER ...................................................37
FA, FB, FC, FK COIL/CONDENSATE PAN
REMOVAL AND REPLACEMENT..........................37-38
• A-Coil Units ............................................................................37
• Slope Coil Units......................................................................37
Residential Fan Coil Units
Fig. 1—Typical Fan Coil
FX, FV, 40FKA COIL/CONDENSATE PAN REMOVAL
AND REPLACEMENT ................................................38-40
CARE AND MAINTENANCE...............................................39
• Filter Assembly .......................................................................39
• Cooling Coil, Drain Pan, and Condensate Drain...................39
• Blower Motor and Wheel .......................................................40
FF1A/FF1B/FF1C SERVICE AND
TROUBLESHOOTING................................................40-42
• Fan Motor................................................................................40
• Electric Heater Service............................................................40
• Cleaning or Replacing Refrigerant Flow-Control Device .....42
• Liquid Tube Strainer ...............................................................42
• Sequence of Operation............................................................42
• Care and Maintenance.............................................................42
FD3A SERVICE AND TROUBLESHOOTING...............43-45
• Fan Motor..................................................................................43
• Electric Heater Service..............................................................43
• Cleaning or Replacing Refrigerant Flow-Control Device .......43
• Liquid Tube Strainer .................................................................45
• Care and Maintenance...............................................................45
FG3A SERVICE AND TROUBLESHOOTING....................46
• Service .......................................................................................46
• Maintenance...............................................................................46
FA4A, FB4A, FC4B, FX4A SMART HEAT CIRCUIT
BOARD FUNCTION AND TROUBLESHOOTING..46-50
• PCB Component Layout, Description, and Function...............46
• Unit Functions...........................................................................47
• Smart Heat Operation................................................................48
PURON® (R-410A) QUICK REFERENCE GUIDE.............51
A98023
Manufacturer reserves the right to discontinue, or change at any time, specifications or designs without notice and without incurring obligations.
Book 1 4 Tab 3d 2e
PC 101 Catalog No. 03FA-4A3 Printed in U.S.A. Form F-5SM Pg 1 6-99 Replaces: F-4SM
Page 2
This symbol → indicates a change since the last issue.
SAFETY CONSIDERATIONS
Improper installation, adjustment, alteration, service, maintenance, or use can cause explosion, fire, electrical shock, or other conditions which may cause personal injury or property damage. Consult a qualified installer, service agency, or your distributor or branch for information or assistance. The qualified installer or agency must use factory-authorized kits or accessories when modifying this product. Refer to the individual installation instruc­tions packaged with the kits or accessories for detailed informa­tion.
Follow all safety codes. Wear safety glasses and work gloves. Use quenching cloth for brazing operations. Have fire extinguisher available. Read these instructions thoroughly and follow all warnings or cautions attached to the unit. Consult local building codes and National Electrical Code (NEC) for special installation requirements.
It is important to recognize safety information. This is the safety-alert symbol instructions and manuals, be alert to the potential for personal injury.
Understand the signal words DANGER, WARNING, and CAU­TION. These words are used with the safety-alert symbol. DAN­GER identifies the most serious hazards which will result in severe personal injury or death. WARNING signifies hazards which could result in personal injury or death. CAUTION is used to identify unsafe practices which would result in minor personal injury or product and property damage.
Puron (R-410A) systems operate at higher pressures than R-22 systems. Do not use R-22 service equipment or com­ponents on R-410A equipment. Ensure service equipment is rated for R-410A.
The "F" series fan coil units are designed for flexibility in a variety of applications, meeting upflow, horizontal, or downflow require­ments. Units are available in 1-1/2 through 5 ton nominal cooling capacities. Factory-authorized, field-installed electric heater pack­ages are available in 3 through 30 kilowatts.
Before installing or servicing fan coil, always turn off all power to unit. There may be more than 1 disconnect switch. Turn off accessory heater power if applicable. Electrical shock can cause personal injury or death.
The 16 position numbering chart allows identification of all available fan coil units. (See Fig. 2.)
FA4A, FB4A, FC4B, FF1D, FH4A, AND FX4A
FUNCTION AND TROUBLESHOOTING
CES0130003-00 and -01 PCB
Step 1—Printed Circuit Board (PCB) Component Layout and Description
Layout of the actual PCB is depicted in Fig. 3A.
1. The low-voltage stripped leads are used to connect the 24-v side of transformer to indoor thermostat and outdoor section.
. When you see this symbol on the unit or in
INTRODUCTION
UNIT IDENTIFICATION
CIRCUIT BOARD
2. A 5-amp fuse is used to protect the low-voltage transformer secondary.
3. The fan relay is controlled by thermostat and turns fan on and off.
4. A plug is used as the connection for PCB power and electric heaters. Note the pin numbers on plug.
5. A time-delay relay circuit keeps fan motor running for approximately 90 sec after G is de-energized. The time-delay can be defeated by cutting jumper JW1.
Step 2—Unit Functions
TRANSFORMER
1. Proper Wiring of Transformer Primary or High Side Yellow wire from Molex plug is wired to C terminal on
transformer and black wire from PCB relay (normally-open) terminal is wired to 208v or 230v terminal on transformer. Units are factory wired at 230v terminal.
2. Proper Wiring of Transformer Secondary or 24-v Side Red wire of transformer is wired to T terminal on PCB and
brown wire of transformer is wired to C terminal on PCB.
NOTE: T terminal on PCB is used to protect transformer. T terminal is connected through the fuse to R terminal on PCB.
INDOOR FAN
1. Wiring (See Fig. 3B for FF1D typical wiring diagram.) Indoor fan motor yellow lead is wired to C terminal on
transformer. The red, blue, or black speed lead is wired to SPT terminal on fan relay part of PCB. Units are factory wired on medium speed (blue lead connected).
NOTE: Unused fan speed leads must be capped or taped off to prevent direct short to cabinet surface.
2. Functional Control a. Thermostat and Relay Control
When thermostat calls for the fan in cooling, heat pump, heating, or fan-only mode, a 24-vac signal is sent to relay. This causes the relay to close its normally-open contacts, turning on fan. When thermostat no longer calls for the fan, the signal sent to relay is turned off and relay opens causing fan to turn off after a 90-sec fan-off delay.
b. Sequencer/Electric Heat Relay Interlock
The fan will also operate whenever there is a call for electric heat, even if fan relay is not energized. This happens because fan is interlocked with first stage of electric heat through the normally-closed contact of fan relay.
NOTE: The fan interlock is only connected to first stage electric heat W2. W3 and E do not contain an interlock with fan. See outdoor thermostat Installation Instructions when electric heat staging is desired.
ELECTRIC HEAT NOTE: Models FF1A/FF1B/FF1C use sequencers for electric
heat. Model FF1D uses DC rectified relays for electric heat. (See Fig. 3C.)
When thermostat calls for electric heat, a 24-vac signal is sent to sequencer/heat relay through W2, causing first stage to turn on. W3 and E also receive signal if wired in with W2. The signal sent to W2 causes first stage to turn on. If W3 and E are not wired to W2, the sequencers/heat relays can be controlled individually to stage additional electric heat. The sequence control is described in the following section:
2
Page 3
Variations
A - Standard Unit
Minor Series
Coil Type
A - Standard
B - Modular
F - Single Piece
6th Position—Fan Coil
A - Original
Variations
A - Common Unit
⁄2 Ton)
1
Cooling Size
024 (2 Ton)
001 (Multi Tons)
002 (Multi Tons)
018 (1
Electrical
5th Position—Fan Coil
Etc.
A - 115-1-60
N - 208/230-1-60
S - 230-1-50
A98114
Heating Size (KW)
005
010
Etc.
10th, 11th, 12th Positions—Fan Coil
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16
Airflow
1 - Upflow
2 - Downflow
3 - Horizontal
Type of Unit
F - Fan Coil
3
4 - Multipoise
5 - Upflow/Downflow
Major Series
A - Original
B - Second Series
Unit Specifics
A - RNC
B - Standard
C - Deluxe
D - Furred in, Cased
2nd Position—Fan Coil
E - Furred in, Uncased
F - Through the Wall
G - Commercial
H - Standard Electric Furnace
J - Standard Hot Water
K - ICM Motor, High Efficiency
V - ICM Motor, Puron R-410A
X - Standard, Puron R-410A
Fig. 2—Fan Coil 16-Position Numbering System
Page 4
Table 1—Product Offering
MODEL UNIT SIZE DESCRIPTION CABINET
FA4ANF 018-060 Multipoise Single Piece FB4ANB 042-070 Multipoise Modular FB4ANF 018-060 Multipoise Single Piece
FB4ASB 042-060
FB4ASF 018-060 FC4BNB 042-070 Multipoise Modular
FC4BNF 024-060 Multipoise Single Piece FD3ANA 018-030 Horizontal Single Piece
FF1A/FF1B/FF1C/FF1D 018-030 Vertical Single Piece
FG3ANA 024, 036, 048, 060 Horizontal/Small Commercial Single Piece FH4ANB 003, 004 Multipoise Modular
FH4ANF 001-004 Multipoise Single Piece
FK4CNB 006 Multipoise Modular
FK4CNF 001-005 Multipoise Single Piece FX4ANF 030-048 Multipoise Single Piece
FX4ANB 060 Multipoise Modular
FV4ANF 002, 003, 005 Multipoise Single Piece
FV4ANB 006 Multipose Modular
NOTE: Multipoise units are approved for upflow, downflow, and horizontal left and right applications.
Multipoise
50 Hz
Multipoise
50 Hz
Modular
Single Piece
Table 2—PSC Fan Motor Speed Taps
MODEL
FA4A 018-036 2 Black — Blue Yellow FA4A 042-060 3 Black Blue Red Yellow FB4A 018-070 3 Black Blue Red Yellow FC4B 024-070 3 Black Blue Red Yellow FD3A 018-030 2 Black — Red Yellow
FF1A/FF1B/FF1C/FF1D 018-030 2 Black — Red Violet**
FG3A 024, 036, 048, 060 1* — — — — FH4A 001-004 3 Black Blue Red Yellow FX4A 030-060 3 Black Blue Red Yellow
*Belt drive. →**Yellow on FF1D
UNIT SIZE
NUMBER OF
SPEEDS
HIGH
SPEED
MEDIUM
SPEED
LOW
SPEED
COMMON
1. W2 When thermostat sends a signal to W2, a 24-vac signal is
applied across sequencer/relay number 1, causing it to close. When sequencer/relay number 1 closes, first stage of electric heat is energized. In straight electric heat, fan is also energized through the normally-closed contacts of fan relay. In cooling, heat pump, or manual fan mode, fan will already be running since fan relay would have been energized. When thermostat stops calling for electric heat, the 24-vac signal to sequencer/relay number 1 turns off and sequencer opens after a delay of 60 to 90 sec. Heaters equipped with relays will be de-energized immediately. When sequencer/relay opens, first stage of heat turns off along with fan, providing thermostat is not calling for the fan.
2. W3 When a signal is sent to W3, a 24-vac signal to
sequencer/relay number 2 causes it to close, with second stage of electric heat turning on. The 24-vac signal applied to sequencer/relay number 1 causes fan to operate. Timing is such that sequencer/relay number 1 will turn on before sequencer/relay number 2. When signal to W3 is turned off, sequencer/relay number 2 opens. If W2 is also satisfied, first stage of electric heat and fan will also turn off, providing thermostat is not calling for the fan.
3. E When thermostat sends a signal to E, a 24-vac signal is sent to
sequencer/relay number 3. The 24-vac signal applied to sequencer/relay number 3 turns on third stage of electric heat. The 24-vac signal applied to sequencer/relay number 1 turns on first stage of electric heat and fan. When thermostat stops calling for electric heat, the signal to sequencers/relays 1, 2, and 3 are turned off, and sequencers/relays open. This causes electric heat to turn off with fan providing thermostat is not calling for the fan.
NOTE: Electric heaters are factory wired with all stages tied together. If independent staging is desired, consult outdoor ther­mostat installation instructions, or corporate thermostat instruc­tions.
Step 3—Troubleshooting the Printed-Circuit Board
Use wiring schematics shown in Fig. 4 and 5 as a guide in troubleshooting PCB unless otherwise noted.
IF FAN WILL NOT TURN ON FROM THERMOSTAT: If There Is No High Voltage To Transformer:
1. Check plug/receptacle connection. This supplies power from heaters to PCB Fan Relay. Be sure plug is connected properly.
2. Check sequencer/relay number 1 and plug wiring. Yellow wire should be connected to pin number 9 of plug and to limit switch. Black wire should be connected to pin number 7 of plug and to sequencer/relay number 1.
4
Page 5
1005-161
C7
R2 R3 C3 R6
R11
Z1
R1
1005-83-161ACPC-E
D2 D1
94V-0
R7
R8
C1C2
R10 R9
R5
R4
®
LR40061
C5
C6
C8
U1
C4
Q1
LOW
C
CESO130003-01
T G R
®
HSCI
TRG C
5 AMP
F1
NC
VOLTAGE FUSE
JW1
FAN
RELAY
K1
NO
SPT
FAN RELAY
Fig. 3A—Fan Coil Printed-Circuit Board
PCB BLOCK WIRING
NO
GRTC
NC
SPT
FUSE
DELAY
TIME
A97020
3. Check field power leads L1 and L2. If these are not receiving power, system cannot function.
If Transformer Has High Voltage Applied To It:
1. Check low-voltage transformer leads R (red) and C (brown). Be sure they are wired to correct locations.
2. Check output voltage of transformer secondary side R (red) and C (brown). Be sure transformer output is between 18 and 30 vac. If transformer output is incorrect and transformer is receiving correct input voltage (208v or 230v), then trans­former needs to be replaced with recommended transformer. If no problem exists with transformer secondary, proceed to items 3 and 4.
3. Check low-voltage fuse shown in Fig. 3A. If fuse is blown, replace it with an identical 5-amp fuse. The transformer cannot supply power to board with fuse blown or loose. If fuse blows when unit has power applied to it, the system most likely has 1 of the following problems:
a. Check all 24-v wiring for an electrical short. b. The maximum load on transformer is 40 VA. If load on
transformer is excessive, the low-voltage 5-amp fuse will blow to protect transformer. If load exceeds VA rating of transformer, a larger VA rated transformer needs to be installed. Check sequencers/relays for excessive current draw.
c. Check wiring of heaters. If a heater is miswired, fuse may
blow. If a heater is miswired, correct miswiring by com­paring it to heater wiring label.
4. Check connections on primary side of transformer. If they are not connected properly, the transformer secondary cannot supply the 24-v signal to energize fan relay. If transformer is receiving correct primary voltage but is not putting out correct secondary voltage, transformer needs to be replaced.
IF ELECTRIC HEAT STAGES WILL NOT TURN ON BUT FAN WILL TURN ON:
If There Is No High Voltage To Transformer:
1. Check plug connection between heaters and board. This supplies power to transformer and fan. Be sure plug is connected properly.
2. Check sequencer/relay number 1 and plug wiring. Yellow wire should be connected to pin number 9 of plug and to limit switch. Black wire should be connected to pin number 7 of plug and to sequencer/relay number 1.
3. Check incoming high-voltage power leads. If these are not receiving power, system cannot function.
If Transformer Has High Voltage Applied To It:
1. Check low-voltage transformer leads R (red) and C (brown). Make sure they are wired to correct location. The unit will not function without proper connections.
2. Check output voltage of transformer secondary side R (red) and C (brown). If transformer output is low (less than 18 vac), refer to items 3 and 4 of previous "If Transformer Has High Voltage Applied To It" section.
If Traces Are Overheated on Back of PCB: Usually whenever a trace is blown on PCB, it means either there
has been a high-voltage short or high voltage has been applied to low-voltage circuit. This can be prevented by making sure PCB is wired correctly before PCB has power applied to it.
IF TRANSFORMER FUSE KEEPS BLOWING: When low-voltage fuse blows, it means transformer would have
blown if fuse had not been in circuit to protect it. The fuse usually blows when there is a high current draw on transformer, high voltage applied to low-voltage circuit, or a direct secondary short. When there is a high current draw on transformer, it is most likely because transformer has been shorted or system is trying to draw more VA than transformer rating allows. When fuse blows because of high voltage, the system has mixed high- and low-voltage signals.
1. Check wiring of sequencers/relays as shown in Fig. 4 and 5. Be sure transformer is not shorting out because thermostat wires are miswired.
2. Check wiring of sequencers/relays as shown in Fig. 4 and 5. Be sure low-voltage and high-voltage wiring is correct.
3. Check VA draw on transformer. If VA draw is more than VA rating of transformer, fuse will blow. If this is the case, replace transformer with one that has a higher VA rating and meets system specifications.
5
Page 6
SCHEMATIC DIAGRAM
SEE RATING PLATE FOR VOLTS & HERTZ
FIELD POWER WIRING
COOLING CONTROLS
ELECTRIC HEAT
SEE NOTE #1
YEL
YEL
YEL
BLK
DISC
YEL
CAP
L1
DISC
YEL
LS2
LS1
SPT
YEL
BRN
FM
RED
DISCONNECT PER NEC
GND
SEE NOTE #6
HTR2
BLK
HTR1
BLK
BLU
BLU
BLK
NC
NO
FR
PCB
BLK
208V
COM
BRN
TRAN
GRN/YEL
GND
G R
T
1
C
230V
BRN
F
RED
8
RELAY 1
4
BLK
BLK
GRY
THERMOSTAT
BLK
6
2
RED ORN
BRN
BARRIER
INDOOR
L1
SEE NOTE #8
YEL
YEL
COM
HI
LO
NOTES:
1. Use copper wire (75¡c min) only between disconnect switch and unit.
2. To be wired in accordance with nec and local codes.
3. If any of the original wire, as supplied, must be replaced, use the same or equivalent type wire.
4. Replace low voltage fuse with no greater than 5 AMP fuse.
5. (2) Speed Motor uses HI (BLK) and LOW (RED).
6. Smaller heaters will have fewer components.
7. Connect R to R, G to G, etc., see outdoor instructions for details.
8. Cooling controls wiring not used with electric heaters.
NOT SUITABLE FOR USE ON SYST EMS EXCEEDING 1 50V TO G ROUND
NE CONVIENT PAS AUX INSTA LLATIONS DE P LUS D E 150 V A LA TERRE
L2
DISC
BLK
BLK
RELAY 1
22 VDC COIL
R E C
ORN
RED
VIO
RWG
C
SEE NOTE #7
OUTDOOR
This compartment must be closed except
when servicing.
ROTATION
324494 -101 RE V. A
Fig. 3B—FF1D Typical Wiring Diagram
L2
DISC
SEE NOTE #8
60A 60A
VIO
GND
GRY
SEE NOTE #5
UNIT
MINIMUM MOTOR SPEED SELECTION
MOTOR SPEED ONE HTR MOTOR SPEED TWO HTR
CAUTION:
ATTENTION:
COMPONENT ARRANGEMENT
LS
LS
RED 24 V
BRN
PCB
FM
LEGEND
HTR
TRAN
NC NO
FR
SPT
BRN BRN
YEL-COM
018 024 030
HTR
SYSTEM TRANSFORMER: 40.0VA
FAN COIL/HEATER: 8.4VA
REMAINING VA AVAILABLE: 31.6VA
RELAY 1
8
6 2
4
01
REC
L2 L1
DISC
GND
RED-LOW BLK-HI
GRN/YEL-GND
FAN MOTOR THERMALLY PROTECTED
CAP
CAPACITOR
COM
COMMON
DISC
DISCONNECT
F
FUSE
FM
FAN MOTOR FIELD POWER WIRING
FR
PCB FAN RELAY
GND
EQUIPMENT GROUND
HTR
HEATER
LS
LIMIT SWITCH MARKED TERMINAL PLUG AND RECEPTACLE
PCB
PRINTED CIRCUIT BOARD
REC
RECTIFIER
SPT
FAN SPEED TAP LOCATION
TRAN
TRANSFORMER UNMARKED TERMINAL
FAN COIL SIZE
LO LO LO
COM
208 V 230 V
C T
1
R G
LO LO
F
CAP
LO
A98229
IF FAN RUNS CONTINUOUSLY:
1. If PCB has no low-voltage power, check blue and black fan leads. These may be switched at sequencer/relay.
2. If PCB has low-voltage power, check fan relay to see if it is opening and closing. It may be stuck in the normally-closed position due to debris in relay.
TRANSFORMER FAILURE:
1. Check 208-v and 230-v transformer connections. They may be miswired.
CIRCUIT BOARD FUNCTION AND TROUBLESHOOTING
HK61GA001 and HK61GA003 Circuit Boards
Step 1—PCB Component Layout and Description
Layout of the actual printed-circuit boards are depicted in Fig. 6 and Fig. 7.
1. The low-voltage terminal board is used to connect the indoor thermostat to the low, 24-v side of the transformer, and to serve as a junction between the indoor thermostat and the outdoor section.
2. Break off the tabs. a. W2-3 — Used to control (stage) the second stage of electric
heat. The first stage controlling electric heat and the indoor fan are interlocked through diodes.
b. W2-E — Used to control (stage) the third stage of electric
heat.
3. A fuse is used to protect the low-voltage transformer.
4. AUX 1 and AUX 2 are connections for the latent capacity control, delay off kit, 2-speed kit and air conditioning acces­sories.
5. F1, F2, F3, and F4 are connections for the indoor fan.
6. EAC1 and EAC2 are 240-v connections, which parallel fan lead connections, for the electronic air cleaner.
7. L1 and L2 are 240-v connections which parallel power input.
8. T1, T2 and T3 are connections for the primary, high-voltage side of the transformer.
9. The fan relay is controlled by the thermostat and turns the fan on and off.
10. A plug is used as the connection for the PCB power and electric heaters. Note the pin numbers on the plug.
11. Diodes provide DC power for the fan relay and the first stage of electric heat: W2, W3 or E.
6
Page 7
312753
HH19ZA945
T-O-D 60TX11
312753
T-O-D 60TX11
L145-55F
C9725
HH19ZA945
C9701
L145-55F
312753
L145-55F
HH19ZA945
C9725
T-O-D 60TX11
NO
NC
SPT
5
FAN
RELAY
FF1D CONTROL BOX
312753
L145-55F
HH19ZA945
C9701
T-O-D 60TX11
FF1A/FF1B/FF1C CONTROL BOX
Fig. 3C—Electric Heater Control Boxes
WARNING
ELECTRIC SHOCK HAZARD
DISCONNECT REMOTE POWER SUPPLY BEFORE OPENING PANEL.
PULL TO OPEN
322861-101 REV. A
PULL TO OPEN
WARNING
ELECTRIC SHOCK HAZARD
DISCONNECT REMOTE POWER SUPPLY BEFORE OPENING PANEL.
322861-101 REV. A
A98184
Step 2—PCB Component Functions
LOW-VOLTAGE TERMINAL BOARD The low-voltage terminal board connects the indoor thermostat to
the outdoor unit as shown in Fig. 8. The terminals are listed as follows along with their functional control.
1. R is used to connect the secondary side of the transformer. The red wire provides low voltage (24v) to the PCB and the thermostat. R is fused on the HK61GA003 board.
2. C is used to connect the brown wire of the thermostat to provide a return path to ground through the fuse which protects the transformer. C is fused on the HK61GA001 board.
3. G is used to control the switching of the relay to turn the fan on through the normally open contact of the relay.
4. Y on the HK61GA001 is used as the junction for the outdoor section’s Y connection which controls the compressor contac­tor for heat pump and cooling modes. The HK61GA003 board contains a 90-sec fan-off delay which begins timing when the Y is de-energized.
5. O is used as a junction for a heat pump reversing valve circuit.
6. W2 is used to turn on the first stage of electric heat which is interlocked with the fan through the normally closed fan relay. Unless the tabs are broken off, all stages of electric heat will turn on when W2 receives a signal from the thermostat.
7. W3 is used to turn on the second stage of electric heat. Note the W2 and W3 tab must be broken off for individual staging to take place. Energizing W3 will always turn on the first stage through the diodes even if the tabs are broken off.
8. E is used to turn on the third stage of electric heat. Note that the W3 and E tab must be broken for this individual staging. Energizing E will always turn on the first stage through the diodes even if the tab is broken off.
9. L is used as a junction to wire a diagnostic light (LED) on selected thermostats.
TRANSFORMER The proper wiring of the transformer on the HK61GA001 board is
INDOOR FAN
1. Wiring--The fan connects to F1, F2, F3, and F4 as shown in Fig. 8. Note that F2 and F3 are dummy terminals. The desired fan speed is connected to F4 and the common is connected to F1. Units are factory wired at medium speed.
2. Functional Control a. Thermostat and Relay Control--When the thermostat calls
for the fan in cooling, heat pump, electric heat, or fan-only mode, a 24-v dc signal is sent to the relay. This causes the relay to close its normally open contacts, thus turning on the fan. When the thermostat no longer calls for the fan, the signal sent to the relay is turned off and the relay opens causing the fan to turn off. The HK61GA003 board contains a 90-sec fan-off delay when Y is de-energized.
b. Sequencer Interlock--The fan will also turn on whenever
there is any call for electric heat, even if the fan relay is not energized. This happens because the fan is interlocked with the first stage of electric heat through the normally closed
contact of the fan relay. ELECTRIC HEAT When the thermostat calls for electric heat, a 24-v signal is sent to
the PCB through W2, causing the first stage to turn on. W3 and E also receive the signal if the tabs are not broken off the PCB. The signal sent to W2 causes the first stage to turn on. If the tabs are broken off the PCB, the sequencers can be controlled individually to stage the electric heat. The sequence control is described in the following section:
7
Page 8
THIS COMPARTMENT MUST BE CLOSED EXCEPT FOR SERVICING
BLOWER MOTOR
ROTATION
NOT SUITABLE FOR USE ON SYSTEMS EXCEEDING 150V TO GROUND
CAUTION:
ATTENTION:
30KW 1PH SCHEMATIC DIAGRAM
FIELD POWER WIRING
HVTB
L1
YEL BLK
FU5
YEL
CB/FU3
YEL
CB/FU1
YEL
9 9
SPT
YEL
YEL
RED-LO
FM
BLU-MED
BRN BRN
CAP
YEL-COM
NOTES:
1. USE COPPER WIRE (75°C MIN) ONLY BETWEEN DISCONNECT SWITCH AND UNIT.
2. TO BE WIRED IN ACCORDANCE WITH NEC AND LOCAL CODES.
3. TRANSFORMER PRIMARY LEADS, BLUE 208V, RED 230V.
4. IF ANY OF THE ORIGINAL WIRE, AS SUPPLIED, MUST BE REPLACED, USE THE SAME OR EQUIVALENT TYPE WIRE.
5. REPLACE LOW VOLTAGE FUSE WITH NO GREATER THAN 5 AMP FUSE.
6. 20KW HEATER USES ONE DOUBLE POLE LS ON MIDDLE TOP ELEMENT.
7. 18, 24 AND 30KW HEATER S USE DOUBLE POLE LIMIT SWITCHES.
8. LARGEST HEATERS ARE SHOWN, SMALLER HEATERS WILL HAVE FEWER ELEMENTS AND COMPONENTS.
9. 1 PHASE HEATERS ARE SHOWN WIRED FOR SINGLE SUPPLY CIRCUI T.
10. USE 60 AMP CLASS K FUSES ONLY, FOR REPLACEMENT.
11. (3) SPEED MOTOR SHOWN. OPTIONAL (2) SPEED MOTOR USES HI (BLU OR RED).
12. CONNECT R TO R, G TO G, ETC., SEE OUTDOOR INSTRUC TION FOR DETAILS.
13. IF WIRE CRIMP IS REMOVED AN EMERGENCY HEAT RELAY (SEE OUTDOOR-THERMOSTAT INSTRUCTIONS)
BLK-HI
GRN/YEL-GND
YEL
YEL
YEL
YEL
YEL
YEL
BLU
7
11
11
7
BLU BLK
NC
NO
FR
PCB
208V
COM
TRAN
LS6
LS4
230V
LS5
LS3
LS2YEL
LS1
BLK
GND
HTR6
HTR5
HTR4
HTR3
HTR2
HTR1
BLK
RED
BRN
SEE RATING PLATE
FOR VOLTS & HERTZ
BLK
BLK
BLK
BLK
BLK
BLK
G R
F
T
1
C
BLU
SEE NOTE #1
12
SEQ 3
10
8
SEQ 2
6
4
SEQ 1
2
ORN
GRY RED
BRN
BRN
C
THERMOSTAT
IS REQUIRED.
DISCONNECT PER NEC
11
FU6
VIO
23 2
W2
WHT
WHT
W2
BLK
CB/FU4
BLK
CB/FU2
RED
16 1
6
W3
BLU
SEE NOTE #13 SEE NOTE #12
OUTDOOR
BLK
SEQ2
SEQ3
GRAY
BRN
E
VIO
UNIT
BLK
9
BLK
7
BLK
5
BLK
3
BLK
1
BLK
SEQ1
3
RED
R BARRIER
INDOOR
(BLK) AND LOW
321214-101 REV. C
L2
4 4
G
BRN
BRN
PLUG
RECP
GRY
CAP
CAPACITOR
COM
COMMON
F
LOW VOLTAGE FUSE
FM
FAN MOTOR FIELD POWER WIRING
FR
PCB FAN RELAY
FU
LINE FUSE
GND
EQUIPMENT GROUND
HVTB
HIGH VOLTAGE TERM BLOCK
HTR
HEATER
LIMIT SWITCH
LS
MARKED TERMINAL PLUG AND RECEPTACLE PRINTED CIRCUIT BOARD
PCB
SEQUENCER
SEQ
TRANSFORMER
TRAN
UNMARKED TERMINAL RECEPTACLE
RECP
CIRCUIT BREAKER
CB
FIELD POWER WIRING
COOLING CONTROL ONLY
FIELD POWER WIRING
LEGEND
L1 L2
YEL
9
208/240VAC 24VAC 24VAC
9
FIELD POWER WIRING
HVTB
L1
Y
FU5
E L
CB/FU3
YEL
CB/FU1
9
208/240VAC 24VAC 24VAC
BLK
7
11
7
11
30KW 3PH SCHEMATIC DIAGRAM
SEE RATING PLATE FOR VOLTS & HERTZ GND
YEL
HTR6
LS6
YEL
HTR5
LS5
YEL
YEL
YEL
YEL
HTR4
LS4
HTR3
LS3
HTR2
LS2YEL
HTR1
LS1
ORN
11 7 23
23
23
DISCONNECT PER NEC
SEE NOTE #1
L3
BLK
12
SEQ 3
BLK
10
BLK
8
SEQ 2
BLK
6
BLK
4
SEQ 1
BLK
2
SEQ1
VIO
11
9
7
5
3
1
RED
BLK
BLK
BLK
BLK
BLK
BLK
PLUG
16
4
16
4
RESP
BLK
L2
FU6
BLK
CB/FU4
BLK
CB/FU2
SEQ2
BRN
SEQ3
BRN
GRAY
PLUG
164
Fig. 4—Wiring Diagram of Sequencer Heater
1. W2--When the thermostat sends a signal to W2, a 24-v dc signal is applied across sequencer number 1, causing it to close. When sequencer number 1 closes, the first stage of electric heat energizes after a short delay. In straight electric heat, the fan is also energized through the normally closed contacts of the fan relay. In cooling, heat pump, or manual fan mode, the fan will already be running since the fan relay would have been energized. When the thermostat stops calling for electric heat, the 24-v dc signal to sequencer number 1 turns off and the sequencer opens after a delay of 60 to 90 sec. When the sequencer opens, the first stage of heat turns off along with the fan, providing that the thermostat is not calling
A94346
for the fan. Note that the electric heat cannot be turned on without the fan being turned on at the same time. This is a fan interlock system.
2. W3--When a signal is sent to W3, 2 control signals are sent out to the sequencers; a 24-v dc signal to sequencer number 1 through the diode interlock, and a 24-v ac signal to sequencer number 2. The 24-v ac signal applied to sequence number 2 causes the sequencer to close, with the second stage of electric heat turning on after a short delay.
The 24-v dc signal applied to sequencer number 1 causes the first stage of electric heat to turn on in the same manner as described in W2 above. Note that W3 is interlocked with the fan, since sequencer number 1 is turned on whenever W3 has a signal sent to
8
Page 9
THIS COMPARTMENT MUST BE CLOSED EXCEPT FO R SERVICING
BLOWER MOTOR
ROTATION
FU3
YEL
BRN
L1
CB1
YEL
SPT
YEL
SCHE MATIC DIAGRAM
SEE RATING PLATE
FOR VOLTS & HERTZ
L3
CB2
YEL
YEL
BLU BLK
BLU
BRN
FM
GND
INTERNAL PROTECTION MAY BE EITHER FUSES OR CIRCUIT BREAKERS
HTR4
LS4
HTR3
LS3
HTR2
LS2
HTR1
LS1
11 7
7
11
BLK
NC
NO
FR
PCB
BLK
C
O
M
GRN
YEL
TRAN
GND
SEE NOTE #1
BLK
BLK BLK
BLK
BLU
G R
F
T
1
C 230V208V
RED
BRN
RELAY 3 4
RELAY 2
8 RELAY 2
4 RELAY 1
4
BLK
RED
BRN
L4
CB2
2
6
2
2
RELAY 1
22 VDC COIL
R E C
3
GRY
RED
BRN
C
R
BARRIER
INDOOR
THERMOSTAT
L4
BLK
BLK
BLK
BLK
22 VDC COIL
22 VDC COIL
RED
GRY
6
1 16
W2
BLU
SEE NOTE #8
OUTDOOR
L2
FU4
RELAY 2
T D R
RELAY 3
R E C
BRN
VIO
G
UNIT
L2
CB1
VIOORN
23 2
WHT
WHT
W
FIELD POWER WIRING DISCONNECT PER NEC
L3
L1
FU1
YEL
YEL
PLUG
9 9
RECP
YEL
CAP
COM
YEL
HI
BLK
MED
BLU
LO
RED
NOTES:
1.Use copper wire (75˚ C m in.) only between disconnect switch and unit.
2.To be wired in accordance with N.E.C. and local codes.
3.If any of the original wire, as supplied, must be replaced, use the same or equivalent type wire.
4.Replace low voltage fuse w ith no greater than 5 amp fuse.
5.Use 60 amp class K fuses only, for replacemen t.
6.(3) speed motor shown. O ptional (2) speed motor uses HI (BLU or RED ).
7.Connect R to R, G to G, etc., see outdoor instruction for details.
8.Smaller heaters will have fewer components.
(BLK) and LOW
324984-101 REV. A
NOT SUITABLE FOR USE O N SYSTEM S EXCEE DING 150V
TO GROUND
ATTENT ION :
CAUTION:
NE CONVIENT PAS AUX INSTALLATIONS DE PLUS DE
RELAY 1
FU2
864
10
RELAY 2 6
8
10
RELAY 3
BRN
BRN
GRY
4 4
6
8
1
CB
CAP
COM
F
FM
FR FU
GND
SPT
150 V A LA T ERRE
COMPONENT ARRANGEMENT
HTR3
3
LS
4
&
HTR4
FAN CO IL/HE ATER: 11.8VA
RED 24 V
FU4 FU2 FU1 FU3
NC NO
FR
SPT
RED-LOW
BLU-MED BLK-HI
GRN/YEL-GND FAN MOTOR THERMALLY PROTECTED
TRAN
BRN
C T
1
F
R G
FM
2
REC
2
4
TDR
2
4
0
TDR
SEE NOTE #6
HTR1
LS1
SYSTEM TRANSFORMER: 40.0VA
REMAINING VA AVAILABLE: 28.2VA
L4 L2 L1 L3
GND
PCB
GND
LEGEND
HTR
CIRCUIT BREAKER CAPACITOR COMM ON LOW V OLTAGE FUSE FAN MOTOR FIEL D POWER WIRING PCB FAN RELAY LINE FUSE EQUIPMENT GROUND FAN SPEED TAP LOCA TIO N
MINIMUM MOTOR SPEED SELECTION
FAN COIL SIZE
018 024 030 036 042 048 060 070
-- LO
HEATER LIMIT SWITC H
LS
MARKED TERM INAL PLUG AND RECEPTACLE PRINTED CIRCUIT
PCB
BOARD RECTIFIER
REC
TRANSFORMER
TRAN
UNMARKED TERMINAL TIME DELAY
TDR
RECTIFIER
MED LO LO
R1
60A 60A
LS2
COM
208 V 230 V
L4 L3
CB1
BRN BRN
YEL-COM
LO LOMOTOR SPEED AT 20 KW --
HTR2
R2
R3
L1
L2
CB2
60A 60A
CAP
it. Timing is such that sequencer number 1 will turn on before sequencer number 2. When the signal to W3 is turned off, sequencer number 2 opens after a short delay. If W2 is also satisfied, the first stage of electric heat and the fan will also turn off, providing the thermostat is not calling for the fan to be on.
E--When the thermostat sends a signal to E 2 signals are sent out to the sequencers. A 24-v ac signal is sent to sequencer number 3 and a 24-v dc signal is sent to sequencer number 1. The 24-v ac signal applied to sequencer number 3 turns on the third stage of electric heat. The 24-v dc signal applied to sequencer 1 turns on the first stage of electric heat and the fan in the same manner as W3. Note that E is also interlocked with the fan.
A99121E
→ Fig. 5—Wiring Diagram of Relay Heater
When the thermostat stops calling for electric heat, the signals to sequencers 1 and 3 are turned off and the sequencers open. This causes the electric heat to turn off with the fan if the thermostat is not calling for the fan.
ACCESSORIES
1. EAC1 and EAC2 for Electronic Air Cleaners a. There are 240-v electronic air cleaner contacts provided at
EAC1 and EAC2. The electronic air cleaner is connected in parallel with the fan so that it is on whenever the fan is on. A 120-v installation is similar in function but connected between EAC2 and neutral of 230-v: 120-v transformer connected to EAC1 and EAC2. Refer to electronic air cleaner literature for further information.
9
Page 10
2FC-1
HK61GA001
LOW VOLTAGE TERMINAL BOARD
2ND STAGE
W2-3W2-E
3RD STAGE
FAN
TDB
ELECTRIC HEAT BREAKOFF TABS FOR STAGING
NOT USED
INTERLOCK
DIODES
PLUG
TRANSFORMER
CONNECTIONS
HK61GA001A
TRANSFORMER
AC LINE
COMMON
101112
DUMMY
FUSE
C
MAX
FUSE
5 AMP
123 456 789
FAN
RELAY
EAC2L2T3T2T1
EAC1L1
240 VAC 240 VAC
24VDC
DUMMY
DUMMY
FAN
COMMON
AUX1
AUX2
F4
F3
F2
F1
(LOW VOLTAGE)
CONNECTIONS FOR VARIOUS ACCESSORIES
FAN CONNECTIONS
Fig. 6—HK61GA001 Printed-Circuit Board
2. AUX1 and AUX2 for 2-Speed Fan Relay Kit a. Use to control fan speed operation, high speed for cooling,
heat pump, and fan-only modes. Low speed is used for electric heat. Fig. 9 shows proper connection for 24-v dc 2-speed fan relay kit. Note that kit’s relay coil is in parallel with fan relay coil on PCB connected to AUX1 and AUX2. Make sure the normally closed contact is connected to the lower speed.
b. The latent capacity control kit is used to control fan speed
operation when the relative humidity is above a set point on
ELECTRONIC AIR CLEANER CONNECTIONS
A97025
humidistat. Humidistat opens and 2-speed fan relay re­mains in normally closed position with fan motor running at a lower speed for maximum humidity control. Fig. 10 shows proper connection for latent capacity control kit. Note that it is connected in the same manner as 2-speed fan relay kit but with relay connected to humidistat (orange wires).
c. Time delay-off relay kit is used to increase the efficiency of
the system by delaying the fan from turning off after the thermostat is satisfied on the HK61GA001 board. The
10
Page 11
FAN INTERLOCK
DIODES AND FAN
TIME DELAY OFF
CIRCUIT
HK61GA003
Y
W3
L
W2
O
E
Y
LOW VOLTAGE TERMINAL BOARD
2FD-1
2ND STAGE
W2-3
W2-E
3RD STAGE
ELECTRIC HEAT BREAKOFF TABS FOR STAGING
PLUG
TRANSFORMER
CONNECTIONS
FAN
RELAY
COMMON
DUMMY
TRANSFORMER
AC LINE
G
FUSE (LOW VOLTAGE)
R
C
MAX
FUSE
5 AMP
36912 25811
R
HK61GA003
14710
AUX1
24VDC
AUX2
CONNECTIONS FOR VARIOUS ACCESSORIES
F4
FAN CONNECTIONS
EAC2L2T3T2T1
EAC1L1
240 VAC 240 VAC
DUMMY
DUMMY
FAN
COMMON
F3
F2
F1
HK61GA003 board has this feature as standard. The proper wiring and mounting of the time delay-off relay kit is shown in Fig. 11.
d. Latent capacity control and time delay-off connections are
shown in Fig. 12, for the HK61GA001 board only.
Step 3—Troubleshooting the Printed-Circuit Board
Use Fig. 13 wiring schematic as a guide in troubleshooting the PCB unless otherwise noted.
ELECTRONIC AIR CLEANER CONNECTIONS
A97026
Fig. 7—HK61GA003 Printed-Circuit Board
IF THE FAN WILL NOT TURN ON FROM THE THERMO­STAT:
If there is no high voltage to the PCB:
1. Check the plug/receptacle connection; this brings power to the PCB. Make sure the plug is connected properly.
2. Check sequencer number 1 and the plug’s wiring; the yellow wire should be connected to pin number 9 of the plug and the limit switch. A black wire should be connected to pin number 7 of the plug and to sequencer number 1.
11
Page 12
LS 6 HTR6 BLK
FU5 FU6
FU3 FU4
FU1 FU2
YEL
YEL
LS 5 HTR5 BLK
YEL
LS 4 HTR4 BLK
YEL
LS 5 HTR5 BLK
YEL
LS 2 HTR2 BLK
YEL
LS 1 HTR1 BLK
YEL
BLU
12 11
SEQ 3
10 9
87
SEQ 2
65
43
SEQ 1
21
BLK
BLK
BLK
BLK
BLK
BLK
BLK
LOW VOLTAGE TERMINAL BOARD
W3
YEL
BLU
BLK
GRAY
BRN
L
W2-3W2-E
W2
O
TO
E
INDOOR
THERMOSTAT
Y
2FC-1
FAN
TDB
G
R
CONNECT E TO E
C TO C ETC.
C
C
GRAY
VIO
SEQ1
ORG
SEQ2SEQ3
BRN
RED
BLK
COMM
COMMON
HK61GA001A
123 456 789
101112
TRANSFORMER
AC LINE
DUMMY
BLU
(208V)
RED
(230V)
RELAY
EAC2L2T3T2T1
EAC1L1
240 VAC 240 VAC
MAX
FUSE
5 AMP
24VDC
DUMMY
DUMMY
COMMON
FAN
AUX1
AUX2
F4
F3
F2
F1
BLU-MED
BLK-HI
RED-LO
CAP
BRN
BRN
YEL-COM
FM
RED-LO BLU-MED
BLK-HI
GRN/YEL-GND
TRAN BRN (24V)
RED (24V)
A97027
Fig. 8—10kw to 20kw Circuits
12
Page 13
F1
A97028
L2
FAN COMMON
UNUSED LEAD
AUX
AUX
ORG
LOW MTR SPD
HI MTR SPD
RED
F3 F2
208/240 VAC
F4
2
1
24 VDC
NC
NO
COM
BLK
FR
CB
O Y R L
LOW VOLTAGE BOARD
W3 W2 E G C
MARKED TERMINAL
2-05868-2A
RELAY WIRING
TWO SPEED FAN
FAN RELAY
UNMARKED TERMINAL
FIELD CTRL WIRING
CIRCUIT BOARD
FACTORY POWER WIRING
FIELD POWER WIRING
FR
CB
NC TO 
LOWER
FAN SPEED
RED
YEL
DUMMY TERMINALS FOR
UNUSED FAN MOTOR
SPEED-TAP 
LEADS
AUX 2
BLK
AUX 1
ORG
NO TO 
HIGHER
FAN SPEED
FAN MOTOR
COMMON LEAD
R
Y
E
O
W2
L
W3
COMMON
F1
F2
F3
F4
VAC AUX2
AUX1
C
G
EAC1
FAN
L1
EAC2
T3
L2
C
DUMMY
T2
T1
LINE
AC
TRANSFORMER
COMMON
Fig. 9—Two-Speed Fan Relay Kit
2SD-1
LOW-VOLTAGE
COIL TERMINALS
13
Page 14
F1
L2
F3 F2
F4
FAN COMMON
UNUSED LEAD
LOW MTR SPD
HI MTR SPD
AUX
AUX
RED
ORG
208/240 VAC
2
1
24 VDC
NC
NO
COM
BLK
FR
NO
ORG
CB
O Y R L
LOW VOLTAGE BOARD
W3 W2 E G C
MARKED TERMINAL
UNMARKED TERMINAL
C
HST
2-05868-1A
CONTROL WIRING
LATENT CAPACITY
FAN RELAY
FIELD CTRL WIRING
CIRCUIT BOARD
FACTORY POWER WIRING
FIELD POWER WIRING
FR
CB
HST HUMIDISTAT
A97029
NO TO 
HIGHER
FAN SPEED
RED
TO HUMIDISTAT
ORANGE WIRES
FAN MOTOR
COMMON LEAD
AUX 2
NC TO 
LOWER
FAN SPEED
YEL
BLK
AUX 1
COMMON
F1
F2
F3
F4
VAC
AUX2
AUX1
C
R
G
Y
E
O
W2
L
W3
EAC1
FAN
L1
EAC2
T3
L2
C
DUMMY
T2
T1
LINE
AC
TRANSFORMER
COMMON
Fig. 10—Latent Capacity Control Kit
2SD-1
14
Page 15
F1
L2
FAN 
MOTOR
SPEED-TAP 
FAN COMMON
UNUSED LEAD
UNUSED LEAD
LEAD
F3 F2
208/240 VAC
F4
2
AUX
1
24 VDC
AUX
NC
2
3
YEL
BLK
2-05868-3A
YEL
CB
SPEED TAP
TO FAN MTR
BLK
TDR
BRN
VIO
NO
COM
1
O Y R L
LOW VOLTAGE BOARD
W3 W2 E G C
FAN 
MOTOR
COMMON 
LEAD
COMMON
F1
FAN
F2
F3
F4
YEL
AUX2
AUX1
BRN
G
TIME DELAY
RELAY WIRING
FAN RELAY
MARKED TERMINAL
UNMARKED TERMINAL
FIELD CTRL WIRING
EAC1
L1
EAC2
L2
C
CIRCUIT BOARD
FACTORY POWER WIRING
FIELD POWER WIRING
FR
CB
TDR TIME DELAY RELAY
T3
DUMMY
T2
COMMON
T1
LINE
AC
TRANSFORMER
A97030
Fig. 11—Time Delay-Off Relay Kit
C
R
G
Y
E
O
W2
L
W3
C
HK61GA001
2FC-1
VIO
15
Page 16
F1
F3 F2
F4
FAN COMMON
UNUSED LEAD
HI MTR SPD
LOW MTR SPD
AUX
AUX
RED
208/240 VAC
2
BLK
1
24 VDC
NC
2
NO
3
COM
1
NC
NO
COM
L2
YEL
TDR
FR
BRN
VIO
ORG
CB
O Y R L
LOW VOLTAGE BOARD
W3 W2 E G C
MARKED TERMINAL
UNMARKED TERMINAL
2-05868-4A
TIME DELAY RELAY
(LATENT CAPACITY)
TWO SPEED FAN RELAY
FIELD CTRL WIRING
FACTORY POWER WIRING
FIELD POWER WIRING
FAN RELAY
CIRCUIT BOARD
A97031
NO TO 
HIGHER
FAN SPEED
ORG
BLU
ORG
ORG
FAN 
MOTOR
NC TO 
LOWER
FAN SPEED
NO
YEL
LEAD
COMMON 
RED
ORG
BLK
YEL
L
C
AUX 2
AUX 1
Y
O
W2
W3
HST
R
E
FR
CB
HST HUMIDSTAT
TDR TIME DELAY RELAY
COMMON
F1
F2
F3
F4
VAC
G
EAC1
EAC2
L2
L1
T3
DUMMY
T2
COMMON
T1
LINE
AC
TRANSFORMER
FAN
BRN
C
G
C
Fig. 12—Latent Capacity Control and Time Delay-Off Relay Kits
2SD-1
VIO
TO HUMIDISTAT
(OPTIONAL, SHOWN
WITH DASHED LINES)
LOW-VOLTAGE
COIL TERMINALS
16
Page 17
FU1 FU2FU3 FU4
YEL BLK
YEL
BLU
BLK
LS 4 HTR4 BLK
YEL
LS 3 HTR3 BLK
YEL
LS 2 HTR2 BLK
YEL
LS 1 HTR1 BLK
YEL
87
SEQ 2
65
43
SEQ 1
21
BLK
BLK
BLK
BLK
C 5 AMP
FUSE
MAX
VIO
SEQ1
RED
123
456
789
RELAY
1011
BLU
BLK
YEL
SEQ2
ORG
BRN
12
PLUG
COMMON
BLK
COMM
R
T1
RED
(24V)
AC LINE
T2
DUMMY
(208V)
TRAN
BLU
T3
RED (230V)
BRN
COMM
L2 EAC2 L1 EAC1
240 VAC 240 VAC COMMON
YEL-COMMON
FM
C
BRN
CAP
GRN/YEL-GND
BRN
C
TERM BOARD
W3 W2
E
L O Y C R G
240 VDC
DUMMY
DUMMY
FAN
INDOOR THERMOSTAT
R L G E COYW2
AUX1 AUX2
F4
F3
F2
F1
RED-LO BLU-MED
BLK-HI
ON TERMINAL BOARD ABOVE
A97032
Fig. 13—Wiring Schematic
17
Page 18
3. Check power leads L1 and L2. If these are not receiving power, the system cannot function.
If the PCB has high voltage applied to it:
1. Check the low-voltage transformer leads, R and C. Make sure they are wired to the correct locations. Note that Fig. 13 shows wiring of the HK61GA001 board.
2. Check the output voltage of the secondary side, R and C, of the transformer. If the circuit board is a HK61GA003, make sure the ground strap is in place from C to the bracket. This strap must be in place to complete the 24-v circuit. Make sure the transformer output is around 24-v ac. If the transformer output is zero-v ac and the transformer is receiving the correct input voltage (208-v or 240-v), then the transformer needs to be replaced with the recommended transformer. If the trans­former output is 24-v ac, then proceed to 3 and 4.
3. Check the low-voltage fuse shown in Fig. 6 and Fig. 7. If the fuse is blown, replace it. The transformer cannot supply power to the board with the fuse blown or loose. If the fuse blows when the unit has power applied to it, the system most likely has 1 of the following problems:
a. If the transformer is shorting out, check the wiring of the
transformer.
b. The maximum load on the transformer is 40 VA. If the load
on the transformer is excessive, the low-voltage, 5-amp fuse will blow to protect the transformer. If the load exceeds the VA rating of the transformer, a larger VA rated transformer needs to be installed. Check the sequencers for excessive current draw.
c. Check the wiring of the heaters. If the heater is miswired,
the fuse may blow. Check the diodes shown in Fig. 14 for signs of overheating. If the heater is miswired, correct the miswiring.
4. Check the T1, T2, and T3 connections on the primary side of the transformer. If they are not connected properly, the low-voltage terminal board cannot supply the 24-v signal to energize the fan relay. If the transformer is receiving the correct primary voltage but is not outputting the correct secondary voltage, the transformer needs to be replaced.
IF THE ELECTRIC HEAT STAGES WILL NOT TURN ON BUT THE FAN WILL TURN ON:
1. Check the wiring of the sequencer. Pay particular attention to the high and low-voltage wiring of the sequencers.
2. Check the plug wiring to make sure that it is wired correctly.
3. Check the voltage to the sequencer; sequencer number 1 receives a 24-vac signal. If it is receiving the correct voltage, check to see if the sequencer is closing. If the sequencer is not closing but is receiving the correct voltage, replace the sequencer. If the sequencer is closing, check the high-voltage wiring as discussed in 1 and 2.
IF THE ELECTRIC HEAT AND THE FAN WILL NOT TURN ON:
If there is no high voltage to the PCB:
1. Check the plug connection. This brings power to the PCB transformer and the fan. Make sure the plug is connected properly.
2. Check sequencer number 1 and the plug wiring. The yellow wire should be connected to pin number 9 of the plug and the limit switch. The black wire should be connected to pin number 7 of the plug and to sequencer number 1.
3. Check incoming high-voltage power leads. If these are not receiving power, the system cannot function.
If the PCB has high-voltage applied to it:
1. Check the low-voltage transformer leads, R and C. Make sure they are wired to the correct location. The unit will not function without proper connections.
2. Check the output voltage of the secondary side, R and C, of the transformer. If the circuit board is an HK61GA003, make sure the ground strap is in place from C to the bracket. This strap must be in place to complete the 24-v circuit. If the transformer output is zero-v ac, refer to "If the PCB has high voltage applied to it" in column 1, numbers 3 and 4.
IF THE TRACES ARE BURNT OFF THE BACK OF THE PCB: Usually whenever there is a trace blown on the PCB it means
either there has been a high-voltage short or high voltage has been applied to the low-voltage circuit. This can be prevented by making sure the PCB is wired correctly before the PCB has power applied to it.
IF THERE ARE BLOWN DIODES:
1. If diodes a and b are blown, it is probable the electric heater plug was miswired. Correct the miswiring. It should be noted the board will need to be replaced if the diode indicated is bad.
2. If any of the c diodes are blown, the fan is miswired to 1 of the low-voltage terminals, AUX1 or AUX2. Check to make sure that the fan leads are connected to the proper terminals as shown in Fig. 13. If the fan is connected properly, make sure that no other high voltage is applied to the AUX terminals.
THE PCB FUSE KEEPS BLOWING: When the low-voltage fuse blows, it means the transformer would
have just blown if the fuse had not been in the circuit to protect it. The fuse usually blows when there is a high current draw on the transformer, high voltage applied to the low-voltage circuit, or a direct secondary short. When there is a high current draw on the transformer, it is most likely because the transformer has been shorted or the system is trying to draw more VA than the transformer is rated for. When the fuse blows because of high voltage, the system has mixed high- and low-voltage signals.
1. Check the transformer and thermostat wiring as shown in Fig.
11. Make sure the transformer is not shorting out by the thermostat wires being miswired.
2. Check the wiring of the sequencers as shown in Fig. 13. Make sure the low-voltage and the high-voltage wiring are con­nected to the proper sequencers.
3. Check the VA draw on the transformer. If the VA draw is more than the VA rating of the transformer, the fuse will blow. If this is the case, replace the transformer with 1 that has a higher VA rating and meets system specifications.
THE FAN RUNS CONTINUOUSLY:
1. If the PCB has no low-voltage power, check the blue and black fan leads. These may be switched at the sequencer.
2. If the PCB has low-voltage power, check the fan relay to see if it is opening and closing. It may be stuck in the normally closed position due to debris in the relay.
3. See Service Manager Bulletin (SMB) 92-3.
TRANSFORMER FAILURE:
1. Check the 208-v and 240-v taps connected to T1, and T3. They may be miswired.
ELECTRIC HEATER FUNCTION AND
TROUBLESHOOTING
This section describes KFA, KFB, KFC, and KFD series electric heaters in exclusion of Smart Heat by examining the functional operation of these heaters.
18
Page 19
W2-3W2-E
BLOWN
DIODE
(b)
BLOWN
DIODE
(a)
HK61GA001A
TRANSFORMER
AC LINE
COMMON
DUMMY
101112
123 456 789
2FC-1
C
RELAY
EAC2L2T3T2T1
EAC1L1
240 VAC 240 VAC
FAN
TDB
FUSE
5 AMP
24VDC
DUMMY
DUMMY
COMMON
MAX
FAN
BLOWN
DIODE
(c)
AUX1
AUX2
F4
F3
F2
F1
Step 1—Description of Electric Heater Components
LIMIT SWITCH The limit switch is a temperature-sensitive control whose function
is to prevent system from overheating in abnormal conditions. The temperature settings often vary from heater to heater due to variations in airflow patterns and element radiant heat conditions. The devices are sized to remain on-line under heat pump condi­tions (115°F air off coil) and minimum CFM, but trip to prevent outlet air conditions above 200°F or excessive component or duct temperatures.
The device itself consists of a bimetallic disc, which when overheated "snaps through" to open a normally-closed high­voltage, high-current switch. When system temperatures cool sufficiently, the switch will automatically reset to its closed position. Normal failure mode for this switch is open.
A97033
Fig. 14—Control Board Noting Diodes
If a limit switch has been determined to be defective, NEVER BYPASS THE LIMIT SWITCH. When replacing limit switch, ensure that it is replaced with a limit switch of identical opening temperature and closing differential. Limits switches are typically color coded to identify their range.
KFA AND KFB SEQUENCER The sequencer is essentially a thermally activated time-delay relay
normally activated by low-voltage control signals from thermostat. The typical sequencer is a 1- or 2-pole normally-open device which energizes within 10 to 30 sec after application of control signal and de-energizes 60 to 90 sec after control signal is removed.
In simplistic terms, the sequencers which we use are nothing more than normally-open limit switches which sit on top of a small resistive heater. When voltage is applied to this heater, a positive temperature coefficient resistor (PTC), heat is supplied to a bimetallic disc which "snaps through" and closes switch.
19
Page 20
Because this is a thermally-activated device, ambient conditions affect the ON/OFF cycle. Higher ambient temperature means shorter ON times and longer OFF times.
These sequencers may be "ganged up" to 3 on a common mounting plate to control up to 6 heater elements. In this situation, PTCs are different in each sequencer to provide a staged ON of a minimum of 10 sec between each sequencer — 3 stages of 2 elements since the KFA and KFB series heaters use sequencers in which both switches of the 2-pole sequencer close simultaneously. Older models used sequencers which had a minimum delay of 10 sec between each switch.
Application of these devices is such that the first switch ON not only turns on first heater element, but also ensures that indoor fan is energized, because first ON is last OFF. This ensures fan remains ON until the last heater de-energizes.
KFC AND KFD ELECTRIC HEAT RELAY KFC and KFD electric heater packages have relays controlling the
Step 2—Troubleshooting KFA, KFB, KFC, and KFD Series Electric Heaters
DISCOLORED WIRE INSULATION AT TERMINAL Check quick-connect terminal at discoloration. Connection may be
loose, creating a high resistance through connection point. FUSE FAILURE
1. Check for shorted wire. Replace wire. Never try to fix wire using electrical tape.
2. Check shorted element. If element is shorted, replace heater.
NO HEAT
1. Check fuse for failure. If fuse has failed, refer to Fuse Failure section.
2. Check for faulty transformer. Check output voltage of trans­former secondary side R (red) and C (brown). Make sure output is between 18 and 30 vac. If output voltage is low and input voltage tests normal, replace transformer.
3. Check for miswired heater plug harness.
4. Check limit switch or sequencer failure. These switches should have failed in open position. If output voltage is zero volts, replace switch.
5. Check heater relay and PCB (KFC and KFD heaters only). Control voltage input to PCB should be 24-vac. Output to relay should be 18-vdc minimum. If input is present but no output, replace PCB. If output is present, replace relay.
HEATER WILL NOT TURN OFF
1. Check low-voltage wiring for miswire.
2. Check for shorted elements to ground.
3. Replace sequencer/relays. They may be stuck closed.
NUISANCE TRIPS
1. Check for low airflow due to dirty filters, blocked registers, or undersized duct.
2. Check blower motor and wheel for proper operation. Exces­sive current draw of motor will cause internal overload to trip.
3. The fan speed may be low.
FAN COIL DESCRIPTION
AND TROUBLESHOOTING
FK4B
The FK4B is similar to the discontinued FK4A as they have both integrated controls and motor (ICM) and their own special circuit board. The greatest difference between the 2 models is the way each goes about delivering air.
Setting up desired airflow on the FK4B is obtained by the selections made on Easy Select™ circuit board. The motor delivers requested airflow as defined by signals received from Easy Select Board and its internal programming. The major difference is that the FK4B motor reacts to changes in system static pressures to maintain constant airflow.
Unlike conventional fan coils where static pressure affects airflow, the FK4B is a constant airflow unit. The blower delivers requested airflow up to about 0.7 in. of static pressure. The ICM2 is pre-programmed and contains airflows for all modes of operation. Blower characteristics (airflow, torque, and speed-vs-static pres­sure) are known from laboratory testing. If any 3 characteristics are known, the fourth is defined.
Requested airflow is known because of Easy Select board con­figuration and thermostat signals. Torque is known because it is directly related to armature current which is measured by motor control. Speed is measured from its generated back EMF. This information is entered into an expression which calculates torque from speed and airflow numbers. If calculation does not match stored blower characteristics, torque is adjusted every 0.8 sec until agreement is reached. The unit does not directly measure static pressure, but does react to a change in static to maintain constant airflow.
Step 1—Integrated Controls and Motor (ICM2)
The ICM2 is similar to the ICM1 used in FK4A series units, but cannot be used as a replacement without some modification to FK4A unit. Consult SMB 93-0052 for motor conversion kit. The electronics of motor are built into rear of motor, deriving the name ICM. (See Fig. 15.)
An ICM is first fed high voltage AC power through the 5-pin connector. The AC power is then rectified to DC by a diode module. After rectification, DC signal is electronically communi­cated and fed in sequential order to 3 stator windings. The frequency of communication pulses determines motor speed. The rotor is permanently magnetized.
An ICM is powered with high voltage at all times. The motor will not run with high voltage alone. Low voltage must be applied to control plug to run motor.
Step 2—PCB Layout and Description NOTE: Layout of actual PCB is depicted in Fig. 16 and 17.
The control is a single PCB which interfaces a variable-speed ICM2 with other system components.
20
Page 21
DO NOT REMOVE
OPTIONAL
SAFETY
GROUND
OPTIONAL SAFETY GROUND
12345
POWER CONNECTOR
9
10 11 12 13 14 15 16
12345678
CONTROL CONNECTOR
DRAIN
HOLE
Fig. 15—FK4B, FK4C and FV4A ICM2 Motor
Connection to heater panel is made through 12-circuit connector P1. Connections to thermostat are made at screw terminals. Line voltage for ICM2 is made through 7-circuit connector P2. Eighteen quick-connect terminals comprise field select taps for motor.
Fuse Data: 5-amp automotive-type ATC/ATO (tan)
32v 200 percent current opening time of 5 sec maximum
ELECTRICAL CONNECTIONS Eighteen 0.187-in quick-connect terminals are used to provide
programming selections for operating modes of ICM2. The 5 selection modes are listed below. For additional information, refer to Easy Select Configuration Taps section.
AUX Heat Range—(Violet Wire) AC/HP Size—(Blue Wire) Type—(Orange Wire) AC/HP CFM Adjust—(Black Wire) AC/HP Time Delay—(Grey Wire)
Step 3—Sequence of Operation
CONTINUOUS FAN MODE The thermostat closes circuit R to G. The G signal is sent directly
to ICM2.
A94079
COOLING MODE—SINGLE SPEED OR 2-SPEED HIGH Thermostat closes circuits R to Y/Y2 and R to O (heat pump only)
COOLING MODE—TWO-SPEED LOW Thermostat closes circuits R to Y1 and R to O (heat pump only).
The Y1 signal is sent directly to ICM2. ELECTRIC HEAT HEATING MODE
Thermostat closes circuit R to W2, W3, or E. The terminal block positions W2, W3, and E are tied together by
HEAT PUMP HEATING MODE—SINGLE SPEED OR 2-SPEED HIGH
Thermostat closes circuit R to Y/Y2 for single speed. A circuit from R to Y1 is also required for 2-speed high. The Y/Y2 signal is sent directly to ICM2.
21
Page 22
LOW VOLTAGE
TERMINAL BLOCK
MOLEX 7-PIN
CONNECTOR (1)
3
⁄16-IN. MALE
FASTON AMP–TYP (21) PLCS
HEATER
5 AMP
MAX
0-5
600
5
FS1
D10
HP-EFFHP-COMFORTAC
R1
HIMEDLO
ENH
D11
R3
JW3
JW4
D3
P1
D1
EASY SELECT
AUX HEAT RANGE
KW
0-30
CFM
VIO
BLU
ORN
BLK
ON OFF090309000
GRY
GROUND
SCREW
REQUIRED
MOTOR
VAC
0-20
1200
1000
AC/HP SIZE
042 036 030 024
TYPE
AC/HP CFM ADJUST
AC/HP
TIME
RED
SEC2 SEC1
XFORM
T1
M1
240
VAC
M2
240
T2
T3
24VAC
0-10 800
DELAY
MOTOR
P2
CES0130007–00
AMP 12-PIN MATE-N-LOCK CONNECTOR (1)
Fig. 16—Easy Select Board
ST1
CESS430023–01
CEBD430023–01
24VDC
AUX1
AUX2
R2
D2 D9 D4
D8 D7 D5 D6
HUM1
HUM2
L R C O
Y/ Y2
Y1
G
JW2
E W2 W3
JW1
PRINTED  CIRCUIT BOARD
W2-E JUMPER 3RD STAGE
W2-W3 JUMPER 2ND STAGE
1
⁄4-IN. MALE FASTON AMP–TYP (9) PLCS
A94076
HEAT PUMP HEATING MODE—TWO-SPEED LOW Thermostat closes R to Y1. The Y1 signal is sent directly to ICM2.
HEAT PUMP HEATING WITH AUXILIARY ELECTRIC HEAT
See previously described modes for circuit paths. In the event that electric heating is called for by thermostat while
heat pump is also operating in either heating or defrost mode, electric heating signal will appear at motor connector pin 1 as described previously. If necessary, the motor will modify its airflow output to provide an airflow which is defined as safe for operation of electric heater.
CFM SELECT CONFIGURATION TAPS The CFM Select taps are used by installer to configure system. The
ICM2 is capable of discerning wave shapes on some of its inputs and uses this capability to modify its operation to a pre­programmed table of airflows and can be modified in response to other inputs such as the need for de-humidification.
ICM2 CONTROL POWER The ICM2 control power is supplied from R circuit through
printed-circuit runs to motor control connector pin 6, through motor control harness to motor. The C side of low-voltage control power circuit is connected by printed-circuit runs to motor connector pins 4 and 5, then through motor control harness to motor.
LOW-VOLTAGE CIRCUIT FUSING AND REFERENCE The low-voltage circuit is fused by a board-mounted 5-amp
automotive-type fuse placed in series with transformer SEC2 and R circuit. The C circuit of transformer is referenced to chassis ground through a printed-circuit run at SEC1 connected to metal standoff marked GROUND SCREW REQUIRED.
NOTE: A ground screw must be in place or erratic motor operation can result.
TRANSFORMER, MOTOR, AND ELECTRIC HEATER POWER CONNECTIONS
The high-voltage (230-vac) power input to board is provided through electric heater connector pins 7 and 9. The high voltage is then connected through printed-circuit runs to motor power con­nections M1 and M2 and transformer power connections T1 and T3. Transformer connection T2 is a dummy terminal used for unused primary power lead. The transformer secondary connec­tions are made at SEC1 and SEC2 connectors.
Step 4—Easy Select Configuration Taps
The FK4B Fan Coil must be configured to operate properly with system components with which it is installed. To successfully configure a basic system (see information printed on circuit board located next to select pins), move the 5 select wires to pins which match components used.
22
Page 23
W2
W3
Y/Y2
ST1
8
E
JW2
ST1
9
ST1
10
SEC1
ST1
3
C
SEC2 PS1
ST1
2
R
ST1
7
G
ST1
5
ST1
4
Y1
ST1
1
L
ST1
3
O
JW3
JW1
JW4
1K 2W
R1
1K 2W
D1
D2
D2
R3
1K 2W
R2
AUX. HEAT
RANGE
AC/HP
SIZE
AC/HP
TYPE
AC/HP
CFM TRIM
AC/HP
DELAY
P1
123
56
4
789
10 11 12
D7
D8
D4
D5
D6
P2
W/W1 G C1 C2 R Y/Y2 Y1
5 – 30
1200
QC1
QC5
AC
QC9
LOW
QC12
ON
OFF
QC15
90
D9
QC2
QC6
0
QC16
HIGH VOLTAGE
D10
D11
5 – 20
1000
QC10
QC13
30 90
QC3
QC7
HP–COM.
MED
QC17
M1
T1
T2
M2
T3
AUX1 HUM1
AUX2
HUM2
5 – 10
800
30 30
QC19
QC4
QC8
QC11
QC14
QC18
RED
0 – 5
600
024030036042
HP–EFF.
HI
0 0
AUXILIARY HEAT RANGE The installer must select the auxiliary heat airflow approved for
application with kw size heater installed. If no heater is installed, skip this step. Each select pin is marked with a range of heaters for which airflow (also marked) is approved. For increased comfort select the narrowest kw range matching the heater size, for example, 0-10 for a 10-kw heater. This airflow must be greater than the minimum CFM for electric heater application with the size system installed for safe and continuous operation. Note that airflow marked is the airflow which will be supplied in emergency heat mode and heating mode on air conditioners when electric heat is primary heating source. To ensure safe heater operation in heat pump heating mode when electric heaters are energized, the ICM2 will run the higher of heat pump efficiency airflow and electric heater airflow. The factory selection is largest heater range approved. (See Fig. 16.)
A94077
Fig. 17—Easy Select Board Circuitry
AC/HP SIZE The factory setting for air conditioner or heat pump size is largest
unit meant for application with model of fan coil purchased. The installer needs to select air conditioner or heat pump size to ensure that airflow delivered falls within proper range for size of unit installed in all operational modes. (See Fig. 16.)
SYSTEM TYPE The type of system must be selected.
1. AC—air conditioner
2. HP-COMFORT—provides same airflow as air conditioner selection (approximately 375 CFM/ton)
3. HP-EFF—provides most efficient airflow for heating and cooling modes (approximately 410 CFM/ton heating and 375 CFM/ton cooling)
The factory setting is AC. (See Fig. 16.)
23
Page 24
Table 3—Male/Female Quick-Connect Terminals (FK4B)
SIZE FEMALE SIZE MALE DESCRIPTION
M2 Motor line voltage connection (230 vac 60 Hz) T3 Transformer line voltage connection (230 vac 60 Hz) T2 Transformer tap storage terminal for 208-vac lead
Secondary connection from transformer (24 vac) This connection is common to chassis ground through eyelet marked GROUND SCREW REQUIRED.
0.250 X 0.032
0.187 X 0.032
SEC1
SEC2 Secondary connection from transformer (24 vac) HUM1 Low voltage ground for humidifier option (24 vdc) HUM2 Low voltage output for humidifier option (24 vdc)
AUX1 Low voltage ground for auxiliary option (24 vdc)
AUX2 Low voltage output for auxiliary option (24 vdc)
M1 Common connection to blower motor T1 Common connection for transformer
RED Common to R screw terminal and SEC2
Table 4—Connections on Single Barrier Strip Mounted, Cross Slotted, Captive Binding Head (FK4B)
SCREW
TERMINAL
W2 Connection for W2 signal from thermostat W3 Connection for W3 signal from outdoor thermostat
E Connection for E signal from thermostat
Y/Y2 Connection for Y signal from thermostat
G Connection for G signal from thermostat O Connection for O signal from thermostat
L
Y1 Connection for low-speed compressor operation
R Connection for R signal to thermostat (24 vac) C Connection for C terminal to thermostat (24 vac common)
This connection is a field termination for use in connecting L lines of thermostat and outdoor unit together. There is no connection of this terminal with control circuity.
DESCRIPTION
Table 5—Connections and Connector (FK4B)
TYPE
CONNECTION
Heater
Connection
ICM2 Motor 7-Pin Header
AC/HP CFM ADJUST Select low, medium, or high airflow. To provide any of these
airflows, AC/HP ADJUST select must be moved to MED position. The factory selection is LO. The adjust selections HI/LO will regulate airflow supplied for all operational modes, except non­heat pump heating modes, +10 percent and -10 percent respec­tively. The adjust selection options are provided to adjust airflow supplied to meet individual installation needs for such things as noise, comfort, and humidity removal. (See Fig. 16.)
TYPE
CONNECTOR
12-Pin
PIN NO. DESCRIPTION
Pin 1 Common to E screw terminal Pin 2 Common to W2 screw terminal Pin 3 Common to C screw terminal, SEC1 terminal, and chassis ground Pin 4 Common to C screw terminal, SEC1 terminal, and chassis ground Pin 5 No connection Pin 6 Common to W3 screw terminal Pin 7 Common to M2 and T3 quick-connects, 230 vac input Pin 8 No connection
Pin 9 Common to M1 and T1 quick-connects, 230 vac input Pin 10 No connection Pin 11 No connection Pin 12 No connection
Pin 1 Diode OR output of E or W3 or W2 thermostat signals
Pin 2 Thermostat G signal
Pin 3 Common to C, SEC1, and chassis ground
Pin 4 Common to C, SEC1, and chassis ground
Pin 5 Common to R and SEC2 (via 5-amp fuse)
Pin 6 Thermostat Y/Y2 signal
Pin 7 Thermostat Y1 signal
AC/HP TIME DELAY Select desired time delay profile. Four motor operation delay
profiles are provided to customize and enhance system operation. (See Fig. 16.) The selection options are:
1. The standard 90 sec off delay (factory setting).
2. No delay option used for servicing unit or when a thermostat is utilized to perform delay functions.
3. A 30 sec on/90 sec off delay profile used when it is desirable
24
to allow system coils time to heat up/cool down prior to
Page 25
airflow. This profile will minimize cold blow in heat pump operation and could enhance system efficiency.
4. ENH, enhanced selection provides a 30 sec on/180 sec off delay at half airflow, adding comfort and efficiency.
Step 5—Troubleshooting PCB
Use Fig. 17 and 18 and Tables 3, 4, and 5 as guides in troubleshooting PCB unless otherwise noted.
IF FAN WILL NOT TURN ON FROM THERMOSTAT: If There Is No High Voltage To PCB:
1. Check connection of 12-pin plug from heaters to receptacle on Easy Select board. This supplies power to PCB. Be sure plug is connected properly.
2. Check sequencer number 1 and plug wiring. Yellow wire should be connected to pin number 9 of plug and to limit switch. Black wire should be connected to pin number 7 of plug and to sequencer number 1.
3. Check power leads L1 and L2. If these are not receiving power, system cannot function.
If PCB Has High Voltage Applied To It:
1. Check low-voltage transformer leads (red and brown). Be sure they are wired to correct locations. (See Fig. 16 and 18.)
2. Check output voltage of transformer secondary side SEC2 and SEC1. Be sure transformer output is around 24 vac. If transformer output is zero vac and transformer is receiving correct input voltage (208v or 240v), then transformer needs to be replaced with recommended transformer. If transformer output is 24 vac, proceed to items 3 and 4.
3. Check low-voltage fuse shown in Fig. 16. If fuse is blown, replace it. The transformer cannot supply power to board with fuse blown or loose. If fuse blows when unit has power applied to it, the system most likely has 1 of the following problems:
a. Check control circuit for a short or miswiring problem. b. The maximum load on transformer is 40 VA. If load on
transformer is excessive, the low-voltage 5-amp fuse will blow to protect transformer. If load exceeds VA rating of transformer, a larger VA rated transformer needs to be installed. Check sequencers for excessive current draw.
c. Check wiring of heaters. If a heater is miswired, fuse may
blow. If a heater is miswired, correct miswiring.
4. Check T1, T2, and T3 connections on primary side of transformer. If they are not connected properly, low-voltage terminal board cannot supply 24-v signal to energize fan motor. If transformer is receiving correct primary voltage but is not putting out correct secondary voltage, transformer needs to be replaced.
If There Are Blown Diodes: If diodes are blown, it is probable that electric heater plug is
miswired. Correct miswiring. NOTE: Board will need to be replaced if diode is bad.
If Traces Are Overheated on Back of PCB: Usually whenever there is a trace blown on PCB, it means either
there has been a high-voltage short or high voltage has been applied to low-voltage circuit. This can be prevented by making sure PCB is wired correctly before PCB has power applied to it.
IF PCB FUSE KEEPS BLOWING: When low-voltage fuse blows, it means transformer would have
blown if fuse had not been in circuit to protect it. The fuse usually blows when there is a high current drawn on transformer, high voltage applied to low-voltage circuit, or a direct secondary short. When there is a high current drawn on transformer, it is most likely because transformer has been shorted or system is trying to draw more VA than transformer rating allows. When fuse blows because of high voltage, the system has mixed high- and low-voltage signals.
1. Check transformer and thermostat wiring. (See Fig. 16 and
18.) Be sure transformer is not shorting out because thermostat wires are miswired.
2. Check wiring of sequencers. (See Fig. 16 and 18.) Be sure low-voltage and high-voltage wiring are connected to proper sequencers.
3. Check VA draw on transformer. If VA draw is more than VA rating of transformer, fuse will blow. If this is the case, replace transformer with one that has a higher VA rating and meets system specifications.
Step 6—Troubleshooting ICM2 Fan Motor
IF MOTOR DOES NOT RUN:
1. With power turned off, check all plugs and receptacles on circuit board and at motor for any deformation that may cause a bad connection. Be sure all plugs are placed fully seated.
2. Verify that there are approximately 230v at terminals M1 and M2. If not, determine if high voltage is entering board. It enters through black and yellow wires at pins 7 and 9 in 12-pin plug.
3. Verify that there is a low-voltage control signal to motor. The motor receives its control signals through the 7-pin motor plug P2. The voltage output of each pin in plug will be different for each mode of operation. Table 6 lists circuit board screw terminals that have 24 vac present (powered by thermostat) and lists voltage that is present at each pin of 7-pin plug for each operating mode. Tests should be taken between points listed and common (C screw terminal). If all values of any 1 of operating modes checks OK and motor fails to run, then motor is defective and should be replaced.
IF ELECTRIC HEAT STAGES WILL NOT TURN ON BUT FAN WILL TURN ON:
1. Check wiring of sequencers. Pay particular attention to high­and low-voltage wiring of sequencers.
2. Check plug wiring to make sure that it is wired correctly.
3. Check voltage to sequencer. Sequencer number 1 receives a 24-vac signal. If it is receiving correct voltage, check to see if sequencer is closing. If sequencer is not closing but is receiving correct voltage, replace sequencer. If sequencer is closing, check high-voltage wiring as discussed in items 1 and
2.
IF MOTOR DOES NOT RUN SMOOTHLY: First verify that the cause is not an out-of-balance or damaged
blower wheel. If it is not blower wheel, motor is defective and should be replaced.
IF MOTOR SHAFT DOES NOT ROTATE SMOOTHLY: When manually turning shaft of ICM, the shaft does not rotate
smoothly. The shaft has steps during rotation referred to as motor cogging. The cogging is caused by permanent magnets passing each pole of motor. However, shaft should not require excessive force to turn. If shaft is VERY difficult to turn, motor control or bearings have failed and motor must be replaced.
25
Page 26
THIS COMPARTMENT MUST BE CLOSED EXCEPT FOR SERVICING
BLOWER MOTOR
ROTATION
30KW 1PH SCHEMATIC DIAGRAM
YEL
PLUG 1
LS5
LS6
LS4
LS3
LS2
LS1
GND
DISCONNECT PER NEC
HTR6
BLK
12 11
ORN
SEQ2
SEQ3
SEQ 3
BLK
10 9
BLK
8
SEQ 2
BLK
65
BLK
43
SEQ 1
BLK
21
BLU
BLK
SEQ1
BRN
BRN
GRY
BLK
VIO
YEL ORN GRN
HTR5
HTR4
HTR3
HTR2
HTR1
RED
SEE RATING PLATE
FOR VOLTS & HERTZ
BLK
BLKBLK
BLK
7
BLK
BLK
123456789101112
PLUG 2
24567
RED BRN VIO
(SEE NOTE 1)
13
HVTB
L1
YEL
YEL
CB/FU4
YEL
CB/FU2
FIELD POWER WIRING
FU6
YEL
YEL
YEL
YEL
YEL
YEL
BLU
FU5
CB/FU3
CB/FU1
BLK
BLK
BLK
NOT SUITABLE FOR USE ON SYSTEMS
NE CONVIENT PAS AUX INSTALLATIONS
SCHEMATIC DIAGRAM
FIELD POWER WIRING
L2
ORN
GRY RED
BRN
RED
TRAN
BLK
COMMON
RED
BLU
BLK
(SEE NOTE 3)
YEL BLK
9
VIO
BLU
A–C HP–COMFORT HP–EFF
LO
BLK
0/30 30/30 30/30 0/0
7
SEC2
M1
YEL
M2
BLU RED
YEL
54321
PLUG 3
PLUG 4
SEE RATING PLATE
FOR VOLTS & HERTZ
(SEE NOTE 1)
COOLING CONTROL WIRING
COOLING CONTROL ONLY
AUX HEAT RANGE
AC/HP SIZE
TYPE
AC/HP CFM TRIM
MED HI
AC/HP DELAY ON/OFF
1
RECP 2
SEC1
T1
3
6
9
12
2
5
8
11
1
4
7
10
RECP 1
T2 T3
GRN/YEL
YEL
BRN
RED
16
BLU
BLK
GRY
BLK
CAUTION:
EXCEEDING 150V TO GROUND
ATTENTION:
DE PLUS DE 150 V A LA TERRE
DISCONNECT PER NEC
GND
PLUG
7
F
L
R
C
O
Y1
G
E
W
2
W
3
AUX1 HUM1
AUX2 HUM2
24VAC
LVTB
JW2 JW1
OLRY
INDOOR THERMOSTAT
PCB
RECP 3
VIO
ORN
ORN
RED
VIO
192103114125136147158
BRN
ICM
RECP 4
Y E
Y
1
Y
(SEE NOTE 2)
0
W
2
O L R
HPTB
EY
1Y0W2
NOTES:
1. Use copper wire only between disconnect switch and unit.
2. Connect (Y) to (Y), (C) to (C), etc. in pattern shown.
3. Transformer primary leads: BLUE 208V, RED 230V.
4. To be wired in accordandce with NEC and local codes.
5. If any of the original wire, as supplied, must be replaced, use the same or  equivalent type wire. 
6. Replace low voltage fuse with no greater than 5 amp fuse. 
7. Fuse is wired in series between transformer SEC2 and low voltage "R" circuit. 
8. 20KW heater uses one double pole LS on middle top element.
9. 18, 24 and 30KW heaters use double pole limit switches.
10. Largest heaters are shown, smaller heaters will have fewer elements and components.
11. 1 phase heaters are shown wired for single supply circuit. Multiple supply circuits may be wired directly to fuse/C.B.'S.
AUX PCB HPTB LVTB SEQ HTR HVTB HUM 
Fig. 18—FK4B Wiring Diagram
26
- LEGEND -
MARKED TERMINAL UNMARKED TERMINAL FIELD POWER WIRING PLUG AND RECEPTACLE PCB BREAKOFF JUMPER AUXILIARY PRINTED CIRCUIT BOARD HEAT PUMP TERM BRD LOW VOLT TERM BRD SEQUENCER HEATER HIGH VOLTAGE TERMINAL BOX HUMIDIFIER 
320486 - 301 REV. C
LS ICM TRAN GND FU RECP CB F 
LIMIT SWITCH FAN MOTOR TRANSFORMER EQUIPMENT GROUND FUSE RECEPTACLE CIRCUIT BREAKER LOW VOLTAGE FUSE  
A94078
Page 27
Table 6—FK4B Motor Control Test Values
(With 16-pin connector at motor unplugged)
OPERATING MODE
Electric Heating R W2 W3* E* 24 vdc 0 0 0 24 vac 0
1-Speed A/C Cooling R Y/Y2 G 0 24 vac 0 0 24 vac 24 vac 0
2-Speed A/C, Low Speed Cooling R Y1 G 0 24 vac 0 0 24 vac 0 24 vac
2-Speed A/C, High Speed Cooling R Y/Y2 G 0 24 vac 0 0 24 vac 24 vac 0
1-Speed HP Cooling R Y/Y2 G O 0 24 vac 0 0 24 vac 24 vac 0
1-Speed HP Heating R Y/Y2 G 0 24 vac 0 0 24 vac 24 vac 0 2-Speed HP, Low Speed Cooling R Y1 G O 0 24 vac 0 0 24 vac 0 24 vac 2-Speed HP, Low Speed Heating R Y1 G 0 24 vac 0 0 24 vac 0 24 vac
2-Speed HP, High Speed Cooling R Y/Y2 Y1 G O 0 24 vac 0 0 24 vac 24 vac 24 vac 2-Speed HP, High Speed Heating R Y/Y2 Y1 G 0 24 vac 0 0 24 vac 24 vac 24 vac
Continuous Fan R G 0 24 vac 0 0 24 vac 0 0
* Pin1@24vdcwith or without jumpers when ever any individual heater input or any combination of heater inputs are energized. → ** Voltages less than 18 are not recognized on the ICM.
SCREW TERMINALS
HAVING 24 VAC
W
Pin 1GPin 2CPin 3CPin 4RPin 5
** VOLTAGES—7-PIN PLUG P2
Y/Y2
Pin 6YPin 7
IF MOTOR DOES NOT STOP RUNNING
1. Check for good ground between motor ground lead and transformer common lead.
2. If motor continues to run, remove all thermostat wires. If motor stops, replace circuit board.
3. If motor continues to run, remove the 7-pin plug. If motor continues to run, replace motor.
Step 7—Condensed Version of Troubleshooting FK4B Motor and Controls
This section provides a quick summary of how to troubleshoot the FK4B. If more information is needed, refer to appropriate sections of this service manual.
+ MOTOR
- If motor is hard to turn manually, replace motor.
- If motor does not run, check the components listed below
according to their instructions.
- If motor runs in some operation modes and not in others, check for a good ground connection between motor ground lead and circuit board screw marked "ground screw" and check the room thermostat and wiring harness according to instructions listed below.
- If motor does not stop running, remove the 7-pin plug from circuit board. If motor continues to run, replace motor. If motor stops running, it is either the circuit board or thermostat causing the problem. Test whether thermostat is at fault by disconnecting it from the board.
+ CIRCUIT BOARD
- Check 5-amp fuse.
- Check for 230v between terminals M1 and M2. If no voltage is present, check power to board. 230-v power enters the board through the black and yellow lead in the 12-pin plug.
- Check for 24v between SEC1 and SEC2. If no voltage is present, check the transformer.
- Check for burn traces or burnt components. If burn spots are present, replace board.
+ ROOM THERMOSTAT
- Remove thermostat wires from the circuit board.
- Jumper screw terminals (1 at a time) R-G, R-Y/Y2, R-Y1, and R-W2. If motor runs in all cases, thermostat is bad. Replace thermostat. If motor does not run, or runs in some cases but not in others, continue by checking the wiring harness.
+ WIRING HARNESS
- Shut off power to unit.
- Remove 5-pin plug from motor.
Never remove 5-pin high voltage plug from the motor with the power on.
- Remove 16-pin plug from motor.
- Replace 5-pin plug and turn on power.
- Check for 24v between pin-1 and pin-12 on the 16-pin plug. (See Fig. 19.) If no voltage is present, replace wiring harness. If voltage is present, jumper screw terminal R-Y/Y2 on circuit board and check for 24v between pin-12 and pin-14 on 16-pin plug. (See Fig. 19.) If voltage is present, replace harness.
- If 24v is present, the motor is bad. Replace motor.
16 15 14 13 12 11 10 9
8 7 6 5 4 3 2 1
16-PIN PLUG
A94375
Fig. 19—Wiring Harness 16-Pin Plug
Step 8—Accessories
ELECTRONIC AIR CLEANER (EAC) Familiar 230-vac EAC control/power signal EAC1 and EAC2 is
not available, because the ICM2 blower motor used in the FK4B Fan Coil is controlled by low-voltage signals. This signal is replaced by a 24-vdc signal which is provided at circuit board terminals AUX1 and AUX2. (See Fig 16.)
This signal is present when either G or W is present and is active in all heating and cooling modes. Because 24-vdc relays may not be readily available to installer, a kit exists, KFAIR0101ACR, containing a 24-vdc relay which mounts directly inside EAC cabinet. User-supplied 110 vac is switched by relay to power air cleaner when G or W are present. (See Fig. 20 and 21.)
27
Page 28
MOUNT FLUSH WITH  THESE TWO EDGES
A93216
Fig. 20—Mounting KFAIR0101ACR Relay Kit
FAN COIL
AUX1
(C)
RED
AUX2
(G)
RED
24 VAC RELAY
230 VAC OR 115 VAC BRANCH CKT
GND HOT NEUT
BLK
GRN
BLK
NO
COM
WHT
WHT
TO EAC
BLK
A98625
Fig. 21—KFAIR0101ACR Relay Kit
Wiring Schematic
In heat pump applications, the G signal is present in both cooling and heating modes, permitting EAC to be controlled from G signal only. For this application, a user-supplied 24-vac relay can be driven by G terminal eliminating need for relay kit.
FK4B DE-HUMIDIFY MODE NOTE: Humidistat must open on humidity rise. Latent capacities for systems using the FK4B Fan Coil are better
than average systems. If increased latent capacity is an application requirement, the FK4B can be wired to provide this requirement by adjusting its airflow in response to standard humidistat input. Fig.
HUMIDISTAT
RED WIRE
FROM ICM2
MOTOR
HUMIDISTAT WIRING FOR DE-HUMIDIFY MODE
TO PCB TERMINAL MARKED 'RED'
Fig. 22—Humidistat Wiring for De-Humidify Mode
22 illustrates the wiring connections to activate de-humidify mode. Carefully consult product airflow data for cooling and dehumidi­fying mode.
FK4C, FV4A, and 40FKA
The FK4C, FV4A, and 40FKA are similar to the discontinued FK4B as they have both integrated controls and motor (ICM2) and their own special circuit board. The difference is in the software of the ICM2. Adjustments have been made in the CFM to enhance the different modes of operation, such as, increased dehumidification.
Set up of desired airflow is obtained by the selections made on Easy Select circuit board. The motor delivers requested airflow as defined by signals received from Easy Select Board and the ICM2 software programming.
If a Thermidistat is used, additional CFM adjustments are made through the ICM2 for super dehumidification in cooling mode. The 40FKA is shipped with the Thermidistat and will have an additional CFM adjustment in heating mode called Comfort Heat. Under certain outdoor conditions in heating, the CFM will lower causing an increase in air discharge temperature for comfort purposes.
Unlike fan coils using induction motors where static pressure affects airflow, the FK4C, FV4A, and 40FKA are constant airflow units. The blower delivers requested airflow regardless of static pressure. Consult FK4C, FV4A, and 40FKA Product Data for static pressure limits. The ICM2 is pre-programmed and contains airflow tables for all modes of operation. Blower characteristics (requested airflow, torque, and speed) are known from laboratory testing. If any 2 characteristics are known, the third is defined.
Requested airflow is known from Easy Select board configuration and thermostat signals. Torque is known because it is directly related to stator current which is measured by motor control. Speed is measured by counting back EMF pulses from stator windings. This information is entered into an expression which calculates torque from speed and airflow numbers. If calculation does not match stored blower characteristics, torque is adjusted until agreement is reached. This calculation and adjustment is per­formed every 0.8 sec while motor is in operation. There is no direct measure of static pressure, but unit does react to a change in static to maintain constant airflow. A change in pressure will result in a change in stator speed and torque. The motor will begin to adjust on the next sampling, calculate new desired speed and torque, and adjust as necessary.
Step 9—Integrated Controls and Motor (ICM2)
An ICM2 is fed high voltage AC power through the 5-pin connector. (See Fig. 23.) The AC power is then rectified to DC by a diode module. After rectification, DC signal is electronically communicated and fed in sequential order to 3 stator windings. The frequency of these commutation pulses determines motor speed. The rotor is permanently magnetized.
An ICM2 is powered with high voltage at all times. The motor will run with high voltage alone. Low voltage must be applied to control plug to run motor.
28
A93215
Page 29
OPTIONAL SAFETY GROUND
DRAIN HOLE
OPTIONAL SAFETY GROUND
CONTROL
POWER
DRAIN HOLE
12345
POWER CONNECTOR
9
10 11 12 13 14 15 16
12345678
CONTROL CONNECTOR
ENDSHIELD
DRAIN HOLE
Fig. 23—FK4C, FV4A, and 40FKA ICM2.3 Motor
Step 10—PCB Layout and Description NOTE: Layout of actual PCB is depicted in Fig. 24 and 25.
The PCB interfaces a variable-speed ICM2 with other system components.
Connection to heater panel is made through 12-circuit connector P1. Connections to thermostat are made at screw terminals. Twenty-one pin terminals comprise field select taps for motor.
Fuse Data: 5-amp automotive-type ATC/ATO (tan)
32v
200 percent current opening time of 5 sec maximum ELECTRICAL CONNECTIONS Twenty-one 0.110-in pin terminals are used to provide program-
ming selections for operating modes of ICM2. The 6 selection modes are listed below. For additional information, refer to Easy Select Configuration Taps section.
AUX Heat Range—(Violet Wire)
AC/HP Size—(Blue Wire) Type—(Orange Wire)
A98201
AC/HP CFM Adjust—(Black Wire) AC/HP Time Delay—(Grey Wire) Continous Fan—(Yellow Wire)
Step 11—Sequence of Operation
CONTINUOUS FAN MODE The thermostat closes circuit R to G. The G signal is sent directly
to ICM2. COOLING MODE—SINGLE SPEED OR 2-SPEED HIGH
Thermostat closes circuits R to Y/Y2 and R to O (heat pump only) for single speed. A circuit from R to Y1 is also required for 2-speed high.
COOLING MODE—TWO-SPEED LOW Thermostat closes circuits R to Y1 and R to O (heat pump only).
The Y1 & O signals are sent to ICM2. COOLING MODE—SUPER DEHUMIDIFICATION CALL
FROM THERMIDISTAT Thermidistat closes circuits R to Y/Y2 and R to O (heat pump
only) for single speed. A circuit from R to Y1 is also required for 2-speed high. Thermidistat call for super dehumidification opens circuit from R to G. The ICM adjusts airflow down to a lower CFM for maximum dehumidification for a period of 10 minutes. If this call continues, outdoor section and ICM shut off for 10
29
Page 30
VIO
®
SEC1
®
SEC2
EASY SELECT
AUX/HEAT KW/CFM
0-30
1075
036 030 024 018
0-20
875
0-10
725
AC/HP SIZE
0-5
625
5 AMP.
MAX.
5
F1
J1
J2
YYWWX
STI
D
W
W
H
R
1
2
BLU
ORN
BLK
WHT
YEL
SYSTEM TYPE
AC HP-COMFORT HP-EFF
AC/HP CFM ADJUST
NOM LO HI
ON/OFF DELAY
0
90
30 90
0 0
CONTINUOUS FAN
LO MED HI YEL
PL1
HEATER/MOTOR
ENH
D4
D5D2
R1
R2
D3
D1
AUX1 HUM1
AUX2
24VAC
1
GRY
HUM2
Y
1
Y/Y
2
G
O
C
CES0130035-00
ELECTRIC HEAT HEATING MODE Thermostat closes circuit R to W1 & W2. The terminal block positions W1 and W2 are tied together by
HEAT PUMP HEATING MODE—SINGLE SPEED OR 2-SPEED HIGH
Thermostat closes circuit R to Y/Y2 for single speed. A circuit from R to Y1 is also required for 2-speed high. The Y/Y2 &Y1 signal is sent to ICM2.
A96430
Fig. 24—Easy Select Board
HEAT PUMP HEATING MODE—COMFORT HEAT WITH 40FKA
HEAT PUMP HEATING MODE—TWO-SPEED LOW Thermostat closes R to Y1. The Y1 signal is sent to ICM2. HEAT PUMP HEATING WITH AUXILIARY ELECTRIC
HEAT Thermostat closes circuits R to Y/Y2 and/or R to Y1 with R to W1
or W2 (and R to O in the case of defrost). The terminal block positions W1 and W2 are tied together by
30
Page 31
SYSTEM DIAGRAM
AUX1 HUM1
AUX2 HUM2
GRY
HEATER/MOTOR
12
11
10
987654321
1
/4"
SEC1 SEC2
1
/4"
1
/4"
5 AMP
J1
D
H
R
1
/4"
W
1
1
/4"
1
/4"
1
/4"
DIODE LOGIC
J2
W
Y
1
Y/Y
G
2
2
O
C
AUX HEAT
KW/CFM
AC/HP
SIZE
SYSTEM
TYPE
Fig. 25—Easy Select Board Schematic
Table 7—Connections on Single Barrier Strip Mounted, Cross Slotted, Captive Binding Head
SCREW
TERMINAL
W2 Connection for W2 signal from thermostat W1 Connection for signal from thermostat W1
Y/Y2
G Connection for G signal from thermostat O Connection for O signal from thermostat
L
Y1 Connection for low-speed compressor operation
R Connection for R signal to thermostat (24 vac) C Connection for C terminal to thermostat (24 vac common)
through use of thermostats. When staging is a requirement, remove J2 jumper and wire in thermostats as is the common practice with other fan coils. To ensure motor operation if any 1 of the inputs is energized, motor will sense input W1 or W2 and run.
In the event that electric heating is called for by thermostat while heat pump is also operating in either heating or defrost mode, electric heating signal will appear at motor connector pins 6 and 7 (W1) and/or pins 4 and 5 (W2) as described previously. If necessary, the motor will modify its airflow output to provide an airflow which is defined as safe for operation of electric heater.
CFM SELECT CONFIGURATION TAPS The CFM Select taps are used by installer to configure system. The
ICM2 is capable of discerning half cycle sine wave on some of its inputs and uses this capability to modify its operation to a
Connection for Y signal from thermostat or high speed compressor operation
This connection is a field termination for use in connecting L lines of thermostat and outdoor unit together. There is no connection of this terminal with control circuity.
AC/HP CFM
ADJUST
DESCRIPTION
pre-programmed table of airflows and can be modified in response to other inputs such as the need for de-humidification.
ICM2 CONTROL POWER The ICM2 control power is supplied from R circuit through
printed-circuit runs to motor control connector pin 8, through motor control harness to motor. The C side of low-voltage control power circuit is connected by printed-circuit runs to motor connector pins 9, 10 and 11 then through motor control harness to motor.
LOW-VOLTAGE CIRCUIT FUSING AND REFERENCE The low-voltage circuit is fused by a board-mounted 5-amp
automotive-type fuse placed in series with transformer SEC2 and
ON/OFF
DELAY
CONTINUOUS
FAN
A96431
31
Page 32
TYPE
CONNECTION
Heater
Connection
Table 8—Connections and Connector (FK4C)
TYPE
CONNECTOR
12-Pin
PIN NO. DESCRIPTION
Pin 1 Common to screw terminal G Pin 2 Common to screw terminal Y/Y2 through diode D3 Pin 3 Common to Y1 through diode D2 Pin 4 Common to W2 screw terminal Pin 5 Common to W2 screw terminal Pin 6 Common to screw terminal W1 screw terminal Pin 7 Common to W1 screw terminal Pin 8 R 24VAC
Pin 9 Common to transformer C Pin 10 Common to transformer C Pin 11 Common to transformer C Pin 12 Common to DH screw terminal
NOTE: The PCB must be mounted with 2 screws and motor ground lead secured to blower housing or erratic motor operation can result.
TRANSFORMER, MOTOR, AND ELECTRIC HEATER POWER CONNECTIONS
Transformer high voltage supplied from electric heater package or high voltage leads through 12-pin heater connector plug/recp 2. The ICM2 power connections are made at the transformer primary terminals. The transformer secondary connections are made at SEC1 and SEC2 connectors.
Step 12—Easy Select Configuration Taps
24.) The FK4C, FV4A, and 40FKA Fan Coils must be configured to
operate properly with system components with which it is in­stalled. To successfully configure a basic system (see information printed on circuit board located next to select pins), move the 6 select wires to pins which match components used, along with homeowner preferences.
AUXILIARY HEAT RANGE
→
The installer must select the auxiliary heat airflow approved for application with kw size heater installed. If no heater is installed, skip this step. Each select pin is marked with a range of heaters for which airflow (also marked) is approved. For increased comfort select the narrowest kw range matching the heater size, for example, 0-10 for a 10-kw heater. This airflow must be greater than the minimum CFM for electric heater application with the size system installed for safe and continuous operation. Note that airflow marked is the airflow which will be supplied in emergency heat mode and heating mode on air conditioners when electric heat is primary heating source. To ensure safe heater operation in heat pump heating mode when electric heaters are energized, the ICM2 will run the higher of heat pump airflow and electric heater airflow. The factory selection is largest heater range approved. (See Fig. 24.)
AC/HP SIZE The factory setting for air conditioner or heat pump size is largest
unit meant for application with model of fan coil purchased. The installer needs to select air conditioner or heat pump size to ensure
that airflow delivered falls within proper range for size of unit installed in all operational modes. (See Fig. 24.)
SYSTEM TYPE The type of system must be selected.
1. AC—air conditioner
2. HP-COMFORT—provides lower airflow than air conditioner selection (approximately 315 CFM/ton) in heating mode. In cooling made supplies 350 CFM/ton.
3. HP-EFF—provides same airflow for heating and cooling modes (approximately 350 CFM/ton).
The factory setting is AC. (See Fig. 24.) AC/HP CFM ADJUST
Select low, nominal, or high airflow. To provide any of these airflows, AC/HP ADJUST select must be moved to NOM position. The factory selection is NOM. The adjust selections HI/LO will regulate airflow supplied for all operational modes, except non­heat pump heating modes, +15 percent and -10 percent respec­tively. The adjust selection options are provided to adjust airflow supplied to meet individual installation needs for such things as noise, comfort, and humidity removal. (See Fig. 24.)
AC/HP TIME DELAY Select desired time delay profile. Four motor operation delay
profiles are provided to customize and enhance system operation. (See Fig. 24.) The selection options are:
1. The standard 90 sec off delay (factory setting 0/90).
2. No delay option used for servicing unit or when a thermostat is utilized to perform delay functions (0/0).
3. A 30 sec on/90 sec off delay profile used when it is desirable to allow system coils time to heat up/cool down prior to airflow. This profile will minimize cold blow in heat pump operation and could enhance system efficiency (30/90).
4. ENH, enhanced selection provides a 30 sec on/150 sec at 70 percent airflow and no off delay.
CONTINOUS FAN Select desired Continuous fan profile LO, MED, or HI. Airflow are
provided to customize and enhance the continous fan functions. (See Fig. 24.) The possible selections are:
1. LO—provides 50% of Y/Y2 Cool airflow.
2. MED—provides 65% of Cool airflow (71% on 006 model).
3. HI—provides 100% of Cool airflow.
The factory setting is LO.
32
Page 33
NOTE: If applied to two-speed unit, do not select continuous fan as high since LO speed cooling will also run at HIGH airflow and insufficient dehumidification may result.
Step 13—Troubleshooting PCB
Use Fig. 25 and 26 and Tables 7 and 8 as guides in troubleshooting PCB unless otherwise noted.
IF FAN WILL NOT TURN ON FROM THERMOSTAT: If There Is No High Voltage To Motor:
1. Check connection of 12-pin plug from heaters to receptacle. This supplies power to transformer and motor. Be sure plug is connected properly.
2. Check power leads L1 and L2. If these are not receiving power, system cannot function.
If Motor Has High Voltage Applied To It:
1. Check low-voltage transformer leads (red and brown). Be sure they are wired to correct locations. (See Fig. 24 and 26.)
2. Check low-voltage fuse shown in Fig. 24. If fuse is blown, replace it. The transformer cannot supply power to board with fuse blown or loose. If fuse blows when unit has power applied to it, the system most likely has 1 of the following problems:
a. Check control circuit for a short or miswiring problem. b. The maximum load on transformer is 40 VA. If load on
transformer is excessive, the low-voltage 5-amp fuse will blow to protect transformer. If load exceeds VA rating of transformer, a larger VA rated transformer needs to be
installed. c. Check sequencers for excessive current draw. d. Check wiring of heaters. If a heater is miswired, fuse may
blow. If a heater is miswired, correct miswiring.
3. Check yellow and black wire connections on primary side of transformer. If they are not connected properly, low-voltage transformer cannot supply 24-v signal to energize fan motor. If transformer is receiving correct primary voltage but is not putting out correct secondary voltage, transformer needs to be replaced.
IF ELECTRIC HEAT STAGES WILL NOT TURN ON BUT FAN WILL TURN ON:
1. Check wiring of sequencers. Pay particular attention to high­and low-voltage wiring of sequencers.
2. Check plug wiring to make sure that it is wired correctly.
3. Check voltage to sequencer. Sequencer number 1 receives a 24-vac signal. If it is receiving correct voltage, check to see if sequencer is closing. If sequencer is not closing but is receiving correct voltage, replace sequencer. If sequencer is closing, check high-voltage wiring as discussed in items 1 and
2.
If Traces Are Overheated on Back of PCB: Usually whenever there is a trace blown on PCB, it means either
there has been a high-voltage short or high voltage has been applied to low-voltage circuit. This can be prevented by making sure PCB is wired correctly before fan coil has power applied to it.
IF PCB FUSE KEEPS BLOWING: When low-voltage fuse blows, it means transformer would have
blown if fuse had not been in circuit to protect it. The fuse usually blows when there is a high current drawn on transformer, high voltage applied to low-voltage circuit, or a direct secondary short. When there is a high current drawn on transformer, it is most likely because transformer has been shorted or system is trying to draw
more va than transformer rating allows. When fuse blows because of high voltage, the system has mixed high- and low-voltage signals.
1. Check transformer and thermostat wiring. (See Fig. 24 and
26.) Be sure transformer is not shorting out because thermostat wires are miswired.
2. Check wiring of sequencers. (See Fig. 24 and 26.) Be sure low-voltage and high-voltage wiring are connected to proper sequencers.
3. Check VA draw on transformer. If VA draw is more than VA rating of transformer, fuse will blow. If this is the case, replace transformer with one that has a higher VA rating.
Step 14—Troubleshooting ICM2 Fan Motor
IF MOTOR DOES NOT RUN:
1. With power turned off, check all plugs and receptacles on circuit board and at motor for any deformation that may cause a bad connection. Be sure all plugs are placed fully seated.
2. Verify that there is approximately 230v.
3. Verify that there is a low-voltage control signal to motor. The motor receives its control signals through the 12-pin motor plug PL1. The voltage output of each pin in plug will be different for each mode of operation. Table 9 lists circuit board screw terminals that have 24 vac present (powered by thermostat) and lists voltage that is present at each pin of 12-pin plug for each operating mode. Tests should be taken between points listed and common (C screw terminal). If all values of any 1 of operating modes check OK and motor fails to run, then motor is defective and should be replaced.
IF MOTOR DOES NOT RUN SMOOTHLY: First verify that the cause is not an out-of-balance or damaged
blower wheel. If it is not blower wheel, motor is defective and should be replaced.
IF MOTOR SHAFT DOES NOT ROTATE SMOOTHLY: When manually turning shaft of ICM, the shaft does not rotate
smoothly. The shaft has steps during rotation referred to as motor cogging. The cogging is caused by permanent magnets passing each pole of motor. However, shaft should not require excessive force to turn. If shaft is VERY difficult to turn, motor control or bearings have failed and motor must be replaced.
IF MOTOR DOES NOT STOP RUNNING
1. Check for good ground between motor ground lead and transformer common lead.
2. If motor continues to run, remove all thermostat wires. If motor stops, check thermostat wiring to thermostat or outdoor unit for shorts or miswire.
This section provides a quick summary of how to troubleshoot the FK4C, FV4A, and 40FKA. If more information is needed, refer to appropriate sections of this service manual.
+ MOTOR
- If motor is hard to turn manually, replace motor.
- If motor does not run, check the components listed below
according to their instructions.
- If motor runs in some operation modes and not in others, check for a good ground connection between motor ground lead and circuit board screw marked "ground screw" and check the room thermostat and wiring harness according to instructions listed below.
33
Page 34
THIS COMPARTMENT MUST BE CLO SED EXCEPT FOR SERVICING
BLOWER MOTOR
ROTATION
20KW 1PH SCHEMATIC DIAGRAM
FIELD POWER WIRING DISCONNECT PER NEC
L3
L1
FU1
YEL
BRN
VIO RED
PLUG 1
L1
CB2
CB1
FU3
YEL
YEL
YEL
YEL
YEL
Com
G
OR BRN
R
VIO
WH BLK
YEL
GRN
ORN
GRY
VIO
RED
WHT
YEL
GRN
PLUG 4
BLU
TRAN
208V
Y
R
N
D
E
BLK
T
21 3
11 10 9
4
12
5
13
6 7
8
16 15 14
YEL
9 9
YEL
12 11 10
9 8 7 6 5 4 3 2 1
SEE RATING PLATE FOR VOLTS & HERTZ
L3
INTERNAL PROTECTION MAY BE EITHER FUSES OR CIRCUIT BREAKERS
HTR4
LS4
HTR3
LS3
HTR2
LS2
HTR1
LS1
BLK
7
11
7
11
RED
BRN
BLK
230V
VIO
BLU
ORN
BLK
YEL
WHT
PLUG 3
5 4 3 2 1
GRN/YEL
GND
BRN
VIO
ORN
WHT
BLU
BLK
BLK
SEE NOTE #1
GND
RELAY 3
BLK
4
RELAY 2
BLK
8
RELAY 2
BLK
4 RELAY 1
BLK
4
BLU
BLK
AUX HEAT KW/CFM
KW
0-30
CFM
1075
VIO
BLU
ORN
BLK
WHT
YEL
PL1
AC/HP SIZE
060 048 042 036
SYSTEM TYPE
AC HP-COMFORT HP-EFF
AC/HP CFM ADJUST
NOM
ON/OFF DELAY
09030
CONTINUOUS FAN
LO MED HI YEL
HEATER / MOTOR
SEC2SEC1
2
6
2
2
0-20
1525
90
L4
CB2
LO
L2
CB1
BLK
BLK
RELAY 1
22 VDC COIL
R E C
ORN
23 2
3
PCB
0-10
1350
0 0
RECP 3
ICM
RECP 4
L4 L2
BLK
BLK
VIO
0-5
1050
HI
HI
FU4
RED
1
FU2
RELAY 2
22 VDC COIL
RELAY 3
22 VDC COIL
GRY
6
1 16
F1
AUX1 HUM1
AUX 2
GRY
T D R
R E C
BRN
HUM2
24 VAC
GRY
NOT SUITABLE FOR USE ON SYSTEMS EXCEEDING
CAUTION:
150V TO GROUND
ATTENTION:
NE CONVIENT PAS AUX INSTALLATIONS DE PLUS
COM
COMMON
F1
LOW VOLTAG E FUSE
ICM
FAN MOTOR FIELD POWER WIRING
FU
LINE FUSE
GND
EQUIPMENT GROUND
HVTB
HIGH VOLTAGE TERM BLOCK
HTR
HEATER
REC
RECTIFIER
COOLING CONTROL ONLY
FIELD
POWER
L1 L2
BRN
BRN
D
R
W
W
Y
Y/Y
G
O
C
4 4
RECP 2
H
1
2
1
2
PLUG 2
WIRING
YEL
9
208/240VAC 24VAC
9117
HTR1
LS1
60A 60A
RELAY 1
OUTDOOR UNITINDOOR THERMOSTAT
864
10
REC
RELAY 2
6
8
10
RELAY 3 6
8
1
L4 L3
CB1
TDR
REC
7
11
HTR3
LS 3
&
L2 L1
CB2
60A 60A
2
2
4
2
4
0
BLK
4
HTR4
NOTES:
1. USE COPPER W IRE (75 ˚C MIN) ONLY BETWEEN DISCONNECT SWITCH AND UNIT.
2. TO BE WIRED IN ACCORDANCE WITH NEC AND LOCAL CODES.
3. TRANSFORMER PRIMARY LEADS, BLUE 208V, RED 230V.
4. IF ANY OF THE ORIGINAL WIRE, AS SUPPLIED, MUST BE REPLACED, USE THE SAME OR EQUIVALENT TYPE WIRE.
5. REPLACE LOW VOLTAGE FUSE WITH NO GREATER THAN 5 AMP FUSE.
6. DUAL CIRCUIT WIRING SHOWN.
7. USE 60 AMP CLASS K FUSES ONLY, FOR REPLACEMENT.
8. CONNECT R TO R, G TO G, ETC. SEE OUTDOOR INSTRUCTION FOR DETAILS.
DE 150 V A LA TERRE
LEGEND
LIMIT SWITCH
LS
MARKED TERMINAL PLUG AND RECEPTACLE PRINTED CIRCUIT BOARD
PCB
TRANSFORMER
TRAN
RECEPTACLE
RECP
CIRCUIT BREAKER
CB
RELAY
R
TIME DELAY RECTIFIER
TDR
FIELD POWER W IRING
SYSTEM TRANSFORMER: 40.0VA
FAN CO IL/HE ATER: 11.8VA
REMAINING VA AVAILABLE: 28.2VA
3
2 23
COMPONENT ARRANGEMENT
HTR2
LS2
R1
PL1
GND
R2
L4 L2
L1 L3
SEC2SEC1
HEATER / MOTOR
RED
24 V
R3
BRN
FU4 FU2 FU1 FU3
PCB
324983-101 REV. A
16
16
4
24VAC
4
TRAN
F1
ICM
PLUG 2
RECP 2
COM
208 V
230 V
D
H R W
1
W
2
Y
1 Y/Y
2
G O C
→ Fig. 26—FK4C, FV4A, and 40FKA Wiring Diagram
A99122E
34
Page 35
Table 9—FK4C Motor Control Test Values
(With 16-pin connector at motor unplugged)
OPERATING MODE
Electric Heating R W1 W2 24 vac 0 0 0 24 vac 0
1-Speed A/C Cooling R Y/Y2 G 0 24 vac 0 0 24 vac -12 vdc 0
2-Speed A/C, Low Speed Cooling R Y1 G 0 24 vac 0 0 24 vac 0 -12 vdc
2-Speed A/C, High Speed Cooling R Y/Y2 G Y1 0 24 vac 0 0 24 vac -12 vdc -12 vdc
1-Speed HP Cooling R Y/Y2 G O 0 24 vac 0 0 24 vac -12 vdc 0
1-Speed HP Heating R Y/Y2 G 0 24 vac 0 0 24 vac -12 vdc 0 2-Speed HP, Low Speed Cooling R Y1 G O 0 24 vac 0 0 24 vac 0 -12 vdc 2-Speed HP, Low Speed Heating R Y1 G 0 24 vac 0 0 24 vac 0 -12 vdc
2-Speed HP, High Speed Cooling R Y/Y2 Y1 G O 0 24 vac 0 0 24 vac -12 vdc -12 vdc 2-Speed HP, High Speed Heating R Y/Y2 Y1 G 0 24 vac 0 0 24 vac -12 vdc -12 vdc
Continuous Fan Low R G 0 24 vac 0 0 24 vac 0 0 Continuous Fan Medium R G 0 24 vac 0 0 24 vac -12 vdc 0 Continuous Fan High R G 0 24 vac 0 0 24 vac 0 -12 vdc
→ ** AC voltages less than 18 are not recognized by the ICM.
SCREW TERMINALS
HAVING 24 VAC
W1
Pin 7GPin 1CPin 9CPin 10RPin 8
+ CIRCUIT BOARD
- Check 5-amp fuse.
- Check for 24v between SEC1 and SEC2. If no voltage is
present, check the transformer.
- Check for burn traces or burnt components. If burn spots are
present, replace board.
+ ROOM THERMOSTAT
- Remove thermostat wires from the circuit board.
- Jumper screw terminals (1 at a time) R-G, R-Y/Y2, R-Y1, and R-W1. If motor runs in all cases, thermostat is bad. Replace thermostat. If motor does not run, or runs in some cases but not in others, continue by checking the wiring harness.
FAN COIL
AUX1
(C)
+ WIRING HARNESS
- Shut off power to unit.
RED
- Remove 5-pin plug from motor.
** VOLTAGES—12-PIN PLUG PL1
Y/Y2
Pin 2
16 15 14 13 12 11 10 9
8 7 6 5 4 3 2 1
16-PIN PLUG
Fig. 27—Wiring Harness 16-Pin Plug
230 VAC OR
AUX2
(G)
RED
115 VAC BRANCH CKT
GND HOT NEUT
BLK
GRN
WHT
Pin 3
Y1
A94375
Never remove 5-pin high voltage plug from the motor with the power on.
- Remove 16-pin plug from motor.
- Replace 5-pin plug and turn on power.
- Check for 24v between pin-1 and pin-12 on the 16-pin plug. (See Fig. 27.) If no voltage is present, replace wiring harness. If voltage is present, jumper screw terminal R-Y/Y2 on circuit board and check for 24v between pin-1 and pin-14 on 16-pin plug. (See Fig. 27.) If voltage is present, check harness connections G, Y1, W1, W2.
- If 24v is not present, the harness is bad. Replace harness.
G — Pin 15 Y1 — Pin 6 W1 — Pin 2 W1 — Pin 13
Step 16—Accessories
ELECTRONIC AIR CLEANER (EAC) 230-vac EAC control/power signal EAC1 and EAC2 is not
available, because the ICM2 blower motor used in the FK4C, FV4A, and 40FKA Fan Coils is controlled by low-voltage signals. This signal is replaced by a 24-vac signal which is provided at circuit board terminals AUX1 and AUX2. (See Fig 24.) This signal
24 VAC RELAY
NO
COM
BLK
→ Fig. 28—KFAIR0201ACR Relay Kit
Wiring Schematic
is present when either G or W is present and is active in all heating and cooling modes. User-supplied 110 vac is switched by relay to power air cleaner when G or W are present. (See Fig. 28.)
FK4C, FV4A, AND 40FKA DE-HUMIDIFY MODE NOTE: Humidistat must open on humidity rise.
35
WHT
TO EAC
BLK
A98625
Page 36
EASY SELECT
BOARD TERMINAL
BLOCK
D
J1
REMOVE
JUMPER
H
HUMIDISTAT
R
A95316
Fig. 29—Humidistat Wiring for De-Humidify Mode
THERMOSTATIC EXPANSION VALVES (TXV)
The FC4B, FK4C, FX4A, FV4A, and 40FKA Fan Coils are factory equipped with a hard shutoff (HSO) TXV.
The hard shutoff TXV has no bleed port and allows no bleed­through after system is shutdown. No pressure equalization occurs. A start capacitor and relay must be installed on single-phase reciprocating compressors to boost torque to compressor motor so it may overcome the unequalized system pressures.
The standard TXV is a bi-flow metering device that is used in condensing and heat pump systems to adjust to changing load conditions by maintaining a preset superheat temperature at outlet of evaporator coil. The volume of refrigerant metered through valve seat is dependent upon the following:
1. Superheat temperature sensed by sensing bulb on suction tube at outlet of evaporator coil. As long as this bulb contains some liquid refrigerant, this temperature is converted into pressure pushing downward on the diaphragm, which opens the valve via push rods.
2. The suction pressure at outlet of evaporator coil is transferred via the external equalizer tube to underside of diaphragm.
3. The needle valve on pin carrier is spring-loaded, which also exerts pressure on underside of diaphragm via push rods, which closes valve. Therefore, bulb pressure equals evapora­tor pressure at outlet of coil plus spring pressure. If load increases, temperature increases at bulb, which increases pressure on topside of diaphragm, which pushes pin carrier away from seal, opening valve and increasing flow of refrig­erant. The increased refrigerant flow causes increased leaving evaporator pressure which is transferred via the equalizer tube to underside of diaphragm, with which the pin carrier spring pressure closes valve. The refrigerant flow is effectively stabilized to load demand with negligible change in superheat.
The bi-flow TXV is used on split system heat pumps. In cooling mode, TXV operates the same as a standard TXV previously explained. However, when system is switched to heating mode of operation, refrigerant flow is reversed. The bi-flow TXV has an additional internal check valve and tubing. These additions allow refrigerant to bypass TXV when refrigerant flow is reversed with only a 1- to 2-psig pressure drop through device. When heat pump switches to defrost mode, refrigerant flows through a completely
Step 1—Problems Affecting TXV
LOW SUCTION PRESSURE
1. Restriction in TXV
2. Low refrigerant charge
3. Low indoor load
4. Low evaporator airflow
HIGH SUCTION PRESSURE
1. Overcharging
2. Sensing bulb not secure to vapor tube
3. High indoor load
4. Large evaporator face area
When installing or removing TXV, wrap TXV with a wet cloth. When reattaching TXV, make sure sensing bulb is in good thermal contact with suction tube.
PISTON BODY CLEANING OR REPLACEMENT
Do not vent refrigerant to atmosphere. Recover during system repair or final unit disposal.
Damage may occur to the scroll compressor if operated at a negative suction pressure during a system pumpdown.
1. Pump down outdoor unit. Close service valves at outdoor unit.
2. Recover remaining refrigerant from tubing and coil through gage port on vapor-tube service valve.
3. Disconnect refrigerant (liquid) tube from piston body. (See Fig. 30.)
4. Avoid damaging seal ring or machined surfaces on piston, bore, and retainer.
5. Using small wire with a hook on end of it, remove piston from body.
TEFLON SEAL
BRASS
HEX BODY
BRASS HEX NUT
PISTON RETAINER
Fig. 30—Refrigerant Flow-Control Device
(For FA, FB, and FF)
When cleaning the piston orifice, be careful not to scratch or enlarge the opening, as this will affect operation.
6. Install new or cleaned piston into body.
36
PISTON
A93530
Page 37
7. Replace seal ring on retainer.
8. Reconnect refrigerant tube to piston body.
9. Pressurize tubing and coil, then leak check.
10. Evacuate tubing and coil as necessary.
Use a backup wrench and do not over tighten, as deformation of the piston body will occur, causing the piston to lodge in a partially open or closed position.
LIQUID TUBE STRAINER
The TXV and refrigerant flow-control device is protected on the indoor coil by a wire mesh strainer. It is located inside the 3/8-in. liquid tube at field braze joint just outside unit casing. Access to strainer is through field braze joint.
FA, FB, FC, FK COIL/CONDENSATE PAN REMOVAL
AND REPLACEMENT
Step 1—A-Coil Units
HORIZONTAL
CONDENSATE
HORIZONTAL PAN CLIP
COIL BRACKET
(4 PER UNIT)
PAN
SCREWS–
DELTA PLATE TO
PAN (4 PER UNIT)
EXPANSION DEVICE (TXV SHOWN)
COIL TOP SEAL
DELTA PLATE
VERTICAL CONDENSATE PAN
A90268
Fig. 31—A-Coil Component Location
If it is determined that system does not have leaks and refrigerant is not contaminated, proceed as follows:
1. Recover system refrigerant. a. Attach manifold/gage set to service valves. b. Front seat (close) liquid tube service valve. c. Start unit in cooling mode. d. Run unit until low pressure switch opens at 27 psig or
vapor pressure reaches 5 psig (35kPa). Do not allow compressor to pump into a vacuum.
e. Turn off electrical supply to outdoor unit. f. Front seat vapor service valve. g. Recover any remaining refrigerant.
2. Turn off electrical supply to indoor unit.
3. Disconnect condensate drain tube.
4. Disconnect liquid and vapor tubes from indoor coil. Use a tubing cutter to cut tubes.
NOTE: If a torch is used to unbraze tube set, protect fitting panel with a wet cloth or braze shield, as necessary.
5. Remove coil access panel.
6. Remove clip securing fitting panel to condensate drain pan. Remove fitting panel.
7. Remove any shipping clips, including horizontal pan clip, and slide coil/condensate pan assembly out of unit.
8. Upflow or Horizontal Applications Only—Remove hori­zontal condensate drain pan from coil/condensate pan assem­bly. (See Fig. 31.)
9. Remove 4 coil brackets. (See Fig. 31.)
10. Remove screws at delta plates and remove coil from vertical condensate drain pan. (See Fig. 31.)
11. Horizontal Applications Only—Remove coil top seal (at­tached with 4 screws) and J-shaped tube from original coil and install it in same position on new coil. (See Fig. 31.)
12. Place coil assembly in plastic condensate pan and secure using 4 screws through delta plate. (See Fig. 31.)
13. Horizontal and Upflow Applications Only—Attach 4 coil brackets to coil/pan assembly. (See Fig. 31.)
14. Horizontal Applications only—Place horizontal condensate pan into position on coil/pan assembly.
NOTE: Installation of horizontal condensate pan is not necessary for upflow or downflow applications.
15. Slide complete assembly into unit.
16. Reinstall fitting panel and reconnect clip securing fitting panel to condensate drain pan.
18. Reinstall coil access panel.
19. Reconnect liquid and vapor refrigerant tubes, and condensate drain tube. Install new liquid line filter-drier.
20. Evacuate tube set and indoor coil to 500 microns, back seat (open) liquid and vapor service valves.
21. Turn on electrical supplies to indoor and outdoor units.
22. Check system refrigerant charge and operation. See "Split­System Residential Air Conditioners and Heat Pumps Service Manual" for further information.
Step 2—Slope Coil Units
If it is determined that system does not have leaks and refrigerant is not contaminated, proceed as follows:
1. Recover system refrigerant. a. Attach manifold/gage set to service valves. b. Front seat (close) liquid tube service valve.
37
Page 38
c. Start unit in cooling mode. d. Run unit until low pressure switch opens at 27 psig or
vapor pressure reaches 5 psig (35kPa). Do not allow
compressor to pump into a vacuum. e. Turn off electrical supply to outdoor unit. f. Front seat vapor service valve. g. Recover any remaining refrigerant.
2. Turn off electrical supply to indoor unit.
3. Disconnect condensate drain tube.
4. Disconnect liquid and vapor tubes from indoor coil. Use either a tubing cutter to cut tubes or a torch to unbraze tubes as required.
NOTE: If a torch is used to unbraze line set, protect fitting panel with a wet cloth or braze shield, as necessary. System contains oil vapors which may ignite when exposed to a flame.
5. Remove coil access and fitting panels.
6. Remove 1 screw securing coil to unit casing.
7. Remove coil/pan assembly from unit.
8. Place assembly on a flat surface. Remove 2 screws securing coil support columns to pan. (See Fig. 32.)
9. Rotate columns 90°, pull away from coil, and remove columns from assembly.
11. Remove coil from condensate pan.
12. Remove coil top seal. (See Fig. 32.)
13. Install new coil into condensate pan using 2 original screws and 2 support columns.
NOTE: Correct coil position in condensate pan is essential to reliable operation.
COIL MOUNTING SCREW
COIL SUPPORT RAIL
SLOPE
COIL
SKI
DRAINPAN
REFRIGERANT
CONNECTIONS
COIL TO
PAN SCREW
(BOTH SIDES)
A98113
Fig. 32—Slope Coil Component Location
14. Install new coil/pan assembly into unit. Secure with 2 screws previously removed from unit casing.
15. Reinstall coil access and fitting panels.
16. Reconnect liquid and vapor refrigerant tubes, and condensate drain tube. Install new liquid line filter-drier.
17. Evacuate tube set and indoor coil to 500 microns, back seat (open) liquid and vapor service valves.
18. Turn on electrical supplies to indoor and outdoor units.
19. Check system refrigerant charge and operation. See "Split­System Residential Air Conditioners and Heat Pumps Service Manual" for further information.
FX4A AND FV4A COIL/CONDENSATE PAN REMOVAL
AND REPLACEMENT (PURON REFRIGERANT)
Step 1—A-Coil Units
If it is determined that system does not have leaks and refrigerant is not contaminated, proceed as follows:
1. Recover system refrigerant. a. Attach manifold/gage set to service valves. b. Front seat (close) liquid tube service valve. c. Start unit in cooling mode. d. Run unit until low pressure switch opens at 50 psig
(350kPa) or vapor pressure reaches 5 psig (35kPa). Do not
allow compressor to pump into a vacuum. e. Turn off electrical supply to outdoor unit. f. Front seat vapor service valve. g. Recover any remaining refrigerant.
2. Turn off electrical supply to indoor unit.
3. Disconnect condensate drain tube.
4. Disconnect liquid and vapor tubes from indoor coil. Use a tubing cutter to cut tubes.
NOTE: If a torch is used to unbraze tube set, protect fitting panel with a wet cloth or braze shield, as necessary.
5. Remove coil access panel.
6. Remove clip securing fitting panel to condensate drain pan. Remove fitting panel.
7. Remove any shipping clips, including horizontal pan clip, and slide coil/condensate pan assembly out of unit.
8. Upflow or Horizontal Applications Only—Remove hori­zontal condensate drain pan from coil/condensate pan assem­bly. (See Fig. 31.)
9. Remove 4 coil brackets. (See Fig. 31.)
10. Remove screws at delta plates and remove coil from vertical condensate drain pan. (See Fig. 31.)
11. Horizontal Applications Only—Remove coil top seal (at­tached with 4 screws) and J-shaped tube from original coil and install it in same position on new coil. (See Fig. 31.)
12. Place coil assembly in plastic condensate pan and secure using 4 screws through delta plate. (See Fig. 31.)
13. Horizontal and Upflow Applications Only—Attach 4 coil brackets to coil/pan assembly. (See Fig. 31.)
38
Page 39
14. Horizontal Applications only—Place horizontal condensate
pan into position on coil/pan assembly.
NOTE: Installation of horizontal condensate pan is not necessary for upflow or downflow applications.
15. Slide complete assembly into unit.
16. Reinstall fitting panel and reconnect clip securing fitting panel to condensate drain pan.
18. Reinstall coil access panel.
19. Reconnect liquid and vapor refrigerant tubes, and condensate drain tube. Install new Puron (R-410A) liquid line filter-drier.
20. Evacuate tube set and indoor coil to 500 microns, back seat (open) liquid and vapor service valves.
21. Turn on electrical supplies to indoor and outdoor units.
Step 2—Slope Coil Units
If it is determined that system does not have leaks and refrigerant is not contaminated, proceed as follows:
1. Recover system refrigerant. a. Attach manifold/gage set to service valves. b. Front seat (close) liquid tube service valve. c. Start unit in cooling mode. d. Run unit until low pressure switch opens at 50 psig
(350kPa) or vapor pressure reaches 5 psig (35kPa). Do not
allow compressor to pump into a vacuum. e. Turn off electrical supply to outdoor unit. f. Front seat vapor service valve. g. Recover any remaining refrigerant.
2. Turn off electrical supply to indoor unit.
3. Disconnect condensate drain tube.
4. Disconnect liquid and vapor tubes from indoor coil. Use either a tubing cutter to cut tubes or a torch to unbraze tubes as required.
NOTE: If a torch is used to unbraze line set, protect fitting panel with a wet cloth or braze shield, as necessary. System contains oil vapors which may ignite when exposed to a flame.
5. Remove coil access and fitting panels.
6. Remove 1 screw securing coil to unit casing.
7. Remove coil/pan assembly from unit.
8. Place assembly on a flat surface. Remove 2 screws securing coil support columns to pan. (See Fig. 32.)
9. Rotate columns 90°, pull away from coil, and remove columns from assembly.
11. Remove coil from condensate pan.
12. Remove coil top seal. (See Fig. 32.)
13. Install new coil into condensate pan using 2 original screws and 2 support columns.
NOTE: Correct coil position in condensate pan is essential to reliable operation.
14. Install new coil/pan assembly into unit. Secure with 2 screws previously removed from unit casing.
15. Reinstall coil access and fitting panels.
16. Reconnect liquid and vapor refrigerant tubes, and condensate drain tube. Install new Puron (R-410A) liquid line filter-drier.
17. Evacuate tube set and indoor coil to 500 microns, back seat (open) liquid and vapor service valves.
18. Turn on electrical supplies to indoor and outdoor units.
CARE AND MAINTENANCE
To continue high performance, and minimize possible equipment failure, it is essential periodic maintenance be performed on this equipment.
The ability to properly perform maintenance on this equipment requires certain mechanical skills and tools. The only consumer service recommended or required is filter maintenance. (See Filter Assembly.)
Disconnect all power to the unit before servicing the field wires or removing the control package. The disconnect (when used) on the access panel does not disconnect power to the line side of the disconnect, but does allow safe service to all other parts of the unit. Electrical shock can cause personal injury or death.
The minimum maintenance requirements for this equipment are as follows:
1. Inspect and clean or replace air filter each month or as required.
2. Inspect cooling coil, drain pan, and condensate drain each cooling season for cleanliness. Clean as necessary. An inspec­tion port is provided on all A-coil delta plates. Remove plastic plug to inspect. Replace plug after inspection.
3. Inspect blower motor and wheel for cleanliness each heating and cooling season. Clean as necessary.
4. Inspect electrical connections for tightness and controls for proper operation each heating and cooling season. Service as necessary.
As with any mechanical equipment, personal injury can result from sharp metal edges. Be careful when removing parts.
Step 1—Filter Assembly
To clean or replace air filter, push plastic connectors toward center of unit and remove filter access panel outward. Push filter up and back into unit. Then slide filter out. Clean filter by using cold water and mild detergent. Rinse and allow filter to dry. No oiling or coating of filter is required. New filters are available from your local distributor. Place filter in slot with cross-mesh binding up or facing cooling coil and replace filter access panel.
Step 2—Cooling Coil, Drain Pan, and Condensate Drain
The cooling coil is easily cleaned when it is dry. Inspect the coil and clean (if necessary) before each cooling season. To check or
39
Page 40
Be careful not to bend coil fins. If coil is coated with oil or grease, clean it with a mild detergent and water solution. Rinse coil thoroughly with clear water. Be careful not to splash water on insulation.
Inspect drain pan and condensate drain at the same time cooling coil is checked. Clean drain pan and condensate drain by removing any foreign matter from pan. Flush pan and drain tube with clear water.
If drain tube is restricted, it can generally be cleared by high­pressure water. Cut plastic line and work outside condensate pan and away from coil to clean drain tube.
centered in inlet opening. If not, loosen setscrew and align as necessary.
5. Attach green wire to blower housing with screw.
6. Secure motor capacitor under strap and tighten strap screw.
7. Slide blower assembly to blower deck. Be sure (once blower is within the unit casing) to force blower assembly toward control box while sliding assembly into unit to ensure that blower assembly engages deck properly.
8. Fasten blower assembly to deck with screws previously removed.
9. Reconnect electrical leads to PCB.
10. Reconnect electrical power to unit and test fan for proper rotation.
Do not use caustic household drain cleaners in the condensate pan or near the coil. Drain cleaners can quickly destroy a coil.
Step 3—Blower Motor and Wheel
Clean blower motor and wheel when cooling coil is cleaned.
Disconnect electrical power before removing any access panels.
To clean blower motor or blower wheel:
1. Remove blower access panel.
2. Remove motor leads from PCB. Note lead location for ease of reassembly.
3. Remove 2 outside screws holding blower/motor assembly against blower-deck flange and slide assembly out of cabinet.
4. Remove screw in strap holding motor capacitor to blower housing and slide capacitor out from under strap. Remove screw with green wire from blower housing. Mark blower wheel, motor, and motor support in relation to blower housing before disassembly to ensure proper reassembly. Note position of blades on wheel.
5. Loosen setscrew holding blower wheel onto motor shaft.
6. Remove 3 bolts holding motor mount to blower housing and slide motor and mount out of housing. Further disassembly should not be necessary as adequate clearance is available.
7. Remove blower wheel from housing by removing cutoff plate from blower housing outlet. Note wheel orientation and cutoff location for reassembly. The blower motor and wheel may be cleaned by using a vacuum with a soft-brush attachment.
8. Remove grease with a mild solvent such as hot water and detergent. Be careful not to disturb balance weights (clips) on blower-wheel vanes. Also, do not drop or bend wheel, as balance will be affected.
To reassemble blower:
1. Place blower wheel back into housing. Be sure to position correctly for proper location.
2. Reassemble cutoff plate to housing using identified holes from disassembly procedure.
3. Position motor and mount in same position as when blower housing was in unit. Secure motor mount on housing, using removed bolts. Make sure mount or motor is grounded to blower housing.
4. Locate blower wheel setscrew over flat on motor shaft. Rotate wheel in housing. It should not rub housing and should be
FF1A/FF1B/FF1C SERVICE AND TROUBLESHOOTING
NOTE: For FF1D Service and Troubleshooting refer to FA4A,
FB4A, FF1D, FH4A, AND FX4A Circuit Board Function and Troubleshooting on page 2. (For FF1D typical wiring diagram, see Fig. 3B.)
Before installation or servicing system, always turn off main power to system. There may be more than 1 disconnect switch. Turn off accessory heater power if applicable. Elec­trical shock can cause personal injury or death.
Step 1—Fan Motor
The motor is 2-speed direct drive. High-speed lead is black, low-speed lead is red, and common lead is violet. Be sure proper blower speed has been selected. For units with electrical heat, low-speed tap can be used. For cooling, use high-speed tap.
The motor is turned on through 2 different routes. The first occurs when thermostat calls for the fan in cooling, heat pump, or fan-only mode. A 24-vac signal is sent to relay, causing relay to close its normally-open contacts, turning fan on. The second occurs when there is a call for electric heat. A 24-vac signal is sent to heater sequencer/relay, causing it to close, directing 230v through the normally-closed contact of fan relay, turning fan on. The fan remains on until sequencer/relay opens. Refer to FF1A/FF1B/FF1C typical wiring diagram. (See Fig. 33.)
If motor does run, test motor for an open winding or a winding shorted to motor case. If any 1 of the 2 is present, replace motor.
Step 2—Electric Heater Service
Service can be completed with heater in place. Shut off power before servicing.
LIMIT SWITCH Refer to Electric Heater Function and Troubleshooting section of
this manual. SEQUENCER Refer to Electric Heater Function and Troubleshooting section of
this manual. TRANSFORMER A 40-VA transformer supplies 24-v power for control circuit.
Check for 208/230v on primary side of transformer. If present, check for 24v on secondary side.
NOTE: Transformer is fused. Do not short circuit. FAN RELAY Relay coil is 24 volts. Check for proper control voltage. Replace
relay if faulty.
40
Page 41
SCHEMATIC DIAGRAM FOR 2, 3, & 5 KW HEATERS
SEE RATING PLATE
FOR VOLTS & HZ
DISCONNECT
L1
FIELD POWER SUPPLY
POWER SUPPLY
POWER SUPPLY
L2
CHASSIS
GROUND
RED
R
VIO
W
ORN
G
BRN
C
SCHEMATIC DIAGRAM FOR 7.5 & 11 KW HEATERS
SEE RATING PLATE
FOR VOLTS & HZ
DISCONNECT
L1
FIELD
L2
CHASSIS GROUND
RED
R
VIO
W
ORN
G
BRN
C
SCHEMATIC DIAGRAM FOR COOLING CONTROL
SEE RATING PLATE
FOR VOLTS & HZ
DISCONNECT
L1
FIELD
L2
CHASSIS GROUND
RED
R
ORN
G
BRN BRN
C
RED BLU
TRANS
SEQ
FR
RED BLU
TRANS
SEQ
FR
RED BLU
TRANS
BLK
BRN
BLK
BRN
BLK
OPTIONAL IFR/TDR
IFR (TDR OPTIONAL) MOTOR
BLK
BLK
43
BLK
SEQ
BRN
56
CHASSIS GROUND
RED
R
ORN
G
OPTIONAL IFR/TDR
IFR (TDR OPTIONAL) MOTOR
BLK
BLK
21
BLK
SEQ
BLK
43
SEQ
BRN
56
CHASSIS GROUND
RED
R
ORN
G
OPTIONAL IFR/TDR
IFR (TDR OPTIONAL) MOTOR
BLK
2
BRN
FR
CHASSIS GROUND
RED
R
ORN
G
13
BLK BRN
42
RED
HTR
BLK
YEL
VIO
AP2
IFR/TD
T
13
BLK BRN
42
RED
BLK
BLK
YEL
VIO
AP2
IFR/TD
T
13
BLK BRN
4
RED
VIO
RED
AP2
IFR/TD
T
C
C
C
BLK
TRANS
B
BRN
HTR2
HTR1
YEL
BLK
TRANS
B
BRN
BLK
B
BRN
BRN
LS
BRN
BRN
56
CHASSIS GROUND
W
BRN
LS2
LS1
BRN
56
BRN
CHASSIS GROUND
W
BRN
TRANS
CHASSIS GROUND
SEQ
VIO
SEQ
VIO
CAP
VIO
CAP
VIO
CAP
BRN
COMPONENT ARRANGEMENT
24VTRANS
LS1 LS2
BLK
208
COM
BLU
HTR1 HTR2
WHEN EQUIPPED
MOTOR SPEED SELECTION
HI = BLACK LOW = RED COMMON = VIO
HEAT PKG.
2 KW 3 KW 5 KW
7.5 KW 11 KW 0 (COOLING)
LS FR IFR IFR/TD SEQ CAP HTR TRANS
UNIT WIRED FOR 230V OPERATION USING
1. BLACK AND RED TRANSFORMER PRIMARY
LEADS. FOR 208V OPERATION, USE BLACK
AND BLUE TRANSFORMER PRIMARY LEADS.
UNUSED TRANSFORMER LEADS MUST BE TAPED
2. AND LOOPED.
IF ANY OF THE ORIGINAL WIRE, AS
3. SUPPLIED, MUST BE REPLACED, USE THE
SAME OR EQUIVALENT WIRE.
FIELD WIRING, USE COPPER CONDUCTORS,
4. ONLY.
FAN RELAY #4 IS A DEAD TERMINAL FOR
5. UNUSED MOTOR LEAD STORAGE. TO CHANGE MOTOR SPEEDS, EXCHANGE THE BLACK AND RED MOTOR LEADS ON THE FAN RELAY.
2 4 5
1 3 6
WHEN EQUIPPED
FIELD WIRE
SIZE
14 12 10
8 6
14
LEGEND
MARKED TERMINAL UNMARKED TERMINAL LIMIT SWITCH FAN RELAY INDOOR FAN RELAY INDOOR FAN RELAY/TIME DELAY SEQUENCER CAPACITOR HEATER TRANSFORMER FIELD POWER WIRING OPTIONAL WIRING FUSE CHASSIS GROUND
NOTES
230
RED
3 2
1 4
SEQ
DISCONNECT
CHASSIS GROUND
TEMP.
RATING
90°C 90°C 90°C 90°C 90°C 90°C
316596 - 401 REV. B
FR
L1
L2
Fig. 33—FF1A/FF1B/FF1C Typical Unit Wiring Label
A91140
41
Page 42
Step 3—Cleaning or Replacing Refrigerant Flow-Control Device
Refer to Fig. 30 and instructions given in Piston Body Cleaning or Replacement section above.
Step 4—Liquid Tube Strainer
The refrigerant flow-control device is protected by a wire mesh strainer. It is located inside the 3/8-in. liquid tube at field braze joint next to flow-control device. Access to strainer is through field braze joint.
Step 5—Sequence of Operation
Refer to Fig. 33. CONDENSING UNIT Cooling When thermostat calls for cooling, the circuit between R and G is
complete and single-pole single-throw relay FR is energized. The normally-open contacts close causing blower to operate. The circuit between R and Y is also complete. This completed circuit causes contactor in outdoor unit to close which starts compressor and outdoor fan.
Heating When thermostat calls for heating and FAN switch is set on
AUTO, the circuit between R and W is complete. The heater sequence SEQ is energized which closes contacts of relay. There will be a time delay. This completed circuit energizes all heating elements HTR and blower motor.
HEAT PUMP Cooling On a call for cooling, the thermostat makes circuits R-O, R-Y, and
R-G. Circuit R-O energizes reversing valve, switching it to cooling position. Circuit R-Y energizes contactor starting outdoor fan motor and compressor. Circuit R-G energizes indoor unit blower relay starting indoor blower motor. When thermostat is satisfied, its contacts open de-energizing contactor reversing valve and blower relay. This stops compressor and fan motors.
Heating On a call for heating, the thermostat makes circuits R-Y and R-G.
Step 6—Care and Maintenance
The minimum maintenance requirements for this equipment are as follows:
1. Inspect and clean or replace air filter each month or as required.
2. Inspect cooling coil, drain pan, and condensate drain each cooling season for cleanliness. Clean as necessary.
3. Inspect blower motor and wheel for cleanliness each heating and cooling season. Clean as necessary.
4. Inspect electrical connections for tightness and controls for proper operation each heating and cooling season. Service as necessary.
As with any mechanical equipment, personal injury can result from sharp metal edges. Be careful when removing parts.
AIR FILTER To clean or replace air filter, grasp it at bottom and lift it out of
unit. Clean filter using cold water. Rinse clean and let dry. Oiling or coating of filter is not required. To replace, stand filter in rack with binding facing coil. Press top edge under access panel.
NOTE: Steel rods in filter prevent it from being pulled into coil. Retain these rods and reinstall after cleaning or before replacement if new filter is used.
Never operate unit without a filter.
COOLING COIL, DRAIN PAN, AND CONDENSATE DRAIN The cooling coil is easily cleaned when it is dry. Inspect coil and
clean (if necessary) before each cooling season. To check or clean cooling coil, remove blower/heater access panel to gain full access to cooling coil. If coil is coated with dirt or lint, vacuum with a soft brush attachment.
Be careful not to bend coil fins. If coil is coated with oil or grease, clean it with a mild detergent-and-water solution. Rinse coil with clear water. Be careful not to splash water onto insulation.
If drain tube is restricted, it can generally be cleared by high­pressure water. Cut plastic line and work outside condensate pan and away from coil to clear drain tube.
NOTE: There MUST be a trap in condensate line. Trap must be at least 3-in. deep, not higher than the bottom of unit condensate drain opening, and pitched downward to an open drain or sump.
Do not use caustic household drain cleaners in condensate pan or near coil. Drain cleaners can quickly destroy coils.
BLOWER MOTOR AND WHEEL Clean blower motor and wheel when cooling coil is cleaned. To clean or service wheel or motor, proceed as follows:
1. Pull unit disconnect (when used) and remove blower access panel.
2. Disconnect motor electrical leads from control box and capacitor. Mark location of wires for reassembly.
3. Remove 3 bolts holding motor mount to blower housing while supporting motor shell with hand.
4. Pull motor inlet ring and blower wheel assembly out of blower housing.
5. With blower wheel, inlet ring, and motor mount still attached to motor, place motor on flat, horizontal surface, shaft up. Mark position of wheel on motor shaft for reassembly.
6. Loosen blower wheel setscrew and remove blower wheel from motor shaft.
7. Clean blower motor and wheel using a vacuum with a soft brush attachment. Remove grease with a mild solvent such as hot water and detergent. Be careful not to disturb balance
42
Page 43
11⁄8″
BLOWER WHEEL
INLET RING
GROMMET
MOTOR
Fig. 34—FF1A/FF1B/FF1C Motor, Inlet Ring, and Blower Wheel Assembly
weights (clips) on blower wheel vanes. Do not drop or bend wheel as balance will be affected.
To reassemble unit, proceed as follows:
1. Place motor with mount attached on flat, horizontal surface with shaft up.
2. Set inlet ring on top of motor mount grommets. Center inlet ring flush on all 3 grommets.
3. Slide blower wheel onto motor shaft with setscrew upward and aligned with shaft flat portion. Vertically position wheel along shaft to position marked during disassembly.
NOTE: If previous shaft was not marked or if replacing previous motor, set blower wheel position by sliding blower wheel along motor shaft to 1-1/8 in. above rubber grommets. (See Fig. 34.)
4. Hold blower wheel in place and carefully tighten setscrew.
5. Position motor and blower wheel assembly to blower housing as originally oriented.
6. Secure motor mount to blower housing using bolts previously removed.
7. Attach green wire to blower housing with screw.
8. Connect electrical and capacitor leads to original terminals.
9. Replace blower access door and tighten all 4 screws.
10. Reinsert disconnect pullout only after blower access door is secured. Test blower for proper operation.
FD3A SERVICE AND TROUBLESHOOTING
Before installation or servicing system, always turn off main power to system. There may be more than 1 disconnect switch. Turn off accessory heater power if applicable. Elec­trical shock can cause personal injury or death.
Step 1—Fan Motor
The motor is 2-speed direct drive. High-speed lead is black, low-speed lead is red, and common lead is yellow.
NOTE: Unused fan speed leads must be tapped off to prevent direct short to cabinet surface.
A86006
The motor is turned on through 2 different routes. The first occurs when thermostat calls for the fan in cooling, heat pump, or fan-only mode. A 24-vac signal is sent to relay, causing relay to close its normally-open contacts, turning fan on. The second occurs when there is a call for electric heat. A 24-vac signal is sent to heater sequencer, causing it to close, directing 230v through the normally-closed contact of fan relay, turning fan on. The fan remains on until sequencer opens. Refer to FD3A typical wiring diagram. (See Fig. 35.)
Step 2—Electric Heater Service
Service can be completed with heater in place. Shut off power before servicing.
LIMIT SWITCH Refer to Electric Heater Function and Troubleshooting section of
this manual. SEQUENCER
Refer to Electric Heater Function and Troubleshooting section of this manual.
TRANSFORMER A 60-VA transformer supplies 24-v power for control circuit.
Check for 208/230-v on primary side of transformer. If present, check for 24-v on secondary side. Replace transformer if faulty.
NOTE: Transformer is fused. Do not short circuit. FAN RELAY
HEATER REMOVAL Disconnect wiring, remove 2 sheet metal screws, and pull heater
out through open hinged access panel. When replacing heater, ensure orientation of heater element is same as when removed.
Step 3—Cleaning or Replacing Refrigerant Flow-Control Device
1. Pump down outdoor unit. Close service valves at outdoor unit.
43
Page 44
L
2
L
1
SEE NOTE #4
FIELD POWER SUPPLY
SEQ SEQ
TB FR
TB
SEQ
TRANS
FR
I
T
R
N
H
D
E
O
R
W2
O
M
R
O
S T A
G
T
C
SCHEMATIC DIAGRAM
T
B
SEQ SEQ
YEL YEL
(OPTIONAL)
(OPTIONAL)
BLK
NOTE #2
RED
1 212
1
BLK
3
BLK
234
BLK BLK
3
BLK
BLK
212
BLK
2
BLK
33
RED
RED
3
FR
NOTE #1
BLK
1
BLU
TRANS
RED
VIO
ORN BRN
BRN BRN
24V
FL-2
FL-1
LO
HI
VIO
ORN BRN
HTR-2
HTR-1
IFM
SEQ
FR
LS-2
LS-1
BRN
YEL
56
BRN
FC
QT
GRN
BRN
BRN BRN BRN
YEL
LS-1
YEL
LS-2
YEL
1
TB
VIO
FC
YEL
1
TB
VIO
LS-2
TRANS
BLK
BLK
FC
SEQ
5
TRANS FR SEQ
5
QT
QT
RED
IFM
HTR-2
2S 14365
BLK BLK
- LEGEND -
FIELD POWER WIRING
FIELD GROUND WIRING
FIELD CONTROL WIRING
FIELD SPLICE
JUNCTION
MARKED CONNECTION
UNMARKED CONNECTION
FAN CAPACITOR
FC
FAN RELAY
FR
HEATER
HTR
INDOOR FAN MOTOR
IFM
LIMIT SWITCH
LS
QUAD TERMINAL
QT
SEQUENCER
SEQ
TERMINAL BLOCK
TB
TRANSFORMER
TRANS
COMPONENT ARRANGEMENT
BRN
YEL
GRNBLK
(OPTIONAL)
LS
E Q
FL-2
FC
YEL BRN
TRANS
2
BRN
BRN
(OPTIONAL)
FUSIBLE LINK
FL
WIRE SLEEVE
BLK YEL
EQUIP. GND.
YEL
RED
LS
BLU BLK
1
HTR-1
FL-1
(OPTIONAL)
RED RED
2
FR
31
NOTES:
1. TRANSFORMER PIGTAILS: BLUE 208V; RED 230V; INSULATE UNUSED LEAD.
2. FAN MOTOR PIGTAILS: RED LOW; BLACK HIGH, INSULATE UNUSED LEAD.
3. FAN MOTOR THERMALLY PROTECTED.
4. SUITABLE FOR USE WITH COPPER OR COPPER CLAD ALUMINUM CONDUCTORS RATED FOR 75°C MINIMUM. FOR COPPER USE 6 AWG. FOR COPPER CLAD ALUMINUM USE 4 AWG.
40DQ500784 REV. C
212
SEE NOTE #4
T
FIELD POWER WIRING
B
1
ORN BRN
VIOVIO
DISCONNECT
FIELD
CONTROL
WIRING
PER
N.E.C.
R
G
C
W2
I
T
N
H
D
E
O
R
O
M
R
O
S T A T
Fig. 35—FD3A Typical Wiring Diagram
A94376
44
Page 45
Damage may occur to the scroll compressor if operated at a negative suction pressure during a system pumpdown.
2. Bleed and (if possible) recover remaining refrigerant from tubing and coil through gage port on vapor-tube service valve.
3. Disconnect liquid refrigerant tube from refrigerant flow­control device. Refer to Fig. 36.
4. Remove refrigerant flow-control device piston retainer. Avoid damaging O-ring or machined surfaces on piston, bore, and retainer.
5. Using small wire with a hook on end of it, remove piston from refrigerant flow-control device body.
THREAD
PROTECTOR
PISTON
BODY
PISTON
RUBBER
O-RING
RETAINER
A92219
Fig. 36—Refrigerant Flow-Control Device
(For FD3A and FG3A)
When cleaning piston orifice, be careful not to scratch or enlarge opening as this will affect operation.
Use a backup wrench and do not overtighten as deformation of refrigerant flow-control device body will occur, causing piston to lodge in a partially open or closed position.
6. Install new or cleaned piston in refrigerant flow-control device body.
7. Install new retainer (because of probable damage which occurred in initial removal).
8. Reconnect refrigerant tube to refrigerant flow-control device.
9. Pressurize tubing and coil, then leak-check.
10. Evacuate tubing and coil as necessary.
Step 4—Liquid Tube Strainer
The refrigerant flow-control device is protected on indoor coil by a wire mesh strainer. If strainer becomes plugged:
1. Complete items 1 and 2 under Cleaning or Replacing Refrig­erant Flow-Control Device section.
2. Loosen flare fitting joint connecting refrigerant flow-control device to coil liquid refrigerant tube.
3. Remove sheet metal screw holding bracket clip in place. Screw is located between coil and refrigerant flow-control device.
4. Pull bracket clip out.
5. Remove refrigerant flow-control device assembly.
6. Pull strainer out of coil liquid refrigerant tube and replace with new strainer.
Step 5—Care and Maintenance
Hinged access panel contains electrical components and is heavy. Support panel when lowering to clean unit to avoid personal injury.
Disconnect electrical power to all circuits before servicing unit. Failure to do so may result in personal injury from electrical shock or moving parts.
As with any mechanical equipment, personal injury can result from sharp metal edges. Be careful when removing parts.
The minimum maintenance requirements for this equipment are as follows:
1. Inspect and clean or replace field-supplied air filter each month or as required.
2. Inspect cooling coil, drain pan, and condensate drain each cooling season for cleanliness. Clean as necessary. (To be performed by trained personnel.)
3. Inspect blower motor and wheel for cleanliness each heating and cooling season. Clean as necessary.
4. Inspect electrical connections for tightness and controls for proper operation each heating and cooling season. Service as necessary.
COOLING COIL, DRAIN PAN, AND CONDENSATE DRAIN Remember to disconnect electrical power before opening hinged
access panel. The cooling coil is easily cleaned when dry. Inspect coil and clean
(if necessary) before each cooling season. If coil inlet face is coated with dirt or lint, vacuum with a soft brush attachment.
Be careful not to bend coil fins. If coil is coated with oil or grease, clean it with a mild detergent-and-hot water solution. Rinse coil with clear water. Be careful not to splash water onto insulation.
NOTE: There MUST be a trap in condensate line. Trap must be at least 3-in. deep, not higher than the bottom of unit condensate drain opening, and pitched downward to an open drain or sump.
BLOWER MOTOR AND WHEEL Clean blower motor and wheel when cooling coil is cleaned.
Lubricate motor every 5 years if motor is used on intermittent operation (thermostat FAN switch at AUTO position), or every 2 years if motor is in continuous operation (thermostat FAN switch at ON position). Remove motor to lubricate. Put approximately 8 drops of SAE 10 nondetergent oil in each oil hole. Do not overoil motor. Plug hole securely so that oil does not drip when hinged access panel is lowered to open position.
Blower motor and wheel may be cleaned using a vacuum with a soft brush attachment. Remove grease with a mild solvent such as
45
Page 46
hot water and detergent. Be careful not to disturb balance weights (clips) on blower wheel vanes. Do not drop or bend wheel as balance will be affected.
FG3A SERVICE AND TROUBLESHOOTING
Step 1—Service
CLEANING OR REPLACING REFRIGERANT FLOW-CONTROL DEVICE
Refer to Fig. 36 and instructions given in FD3A Service and Troubleshooting section above.
Step 2—Maintenance
MOTOR Ball bearing oilers are provided on blower motor. Use electric
motor oil or SAE 10 or 20 nondetergent oil. Check motor mount bracket and base bolts. Tighten as required.
BLOWER Check ball bearings for wear. Ball bearings are self-aligning and
grease packed. Replace as required. Check thrust collars for end play and alignment of wheel. Check blades for accumulation of dirt. Clean as required. Check mounting brackets, base bolts, and isolation material.
See Fig. 37 for diagram of internal wiring for blower coil assembly. Control box (standard 4-in. junction box) is mounted on refrigerant connection side of unit. All leads pass through strain relief where they enter control box. Wiring inside cabinet is located so it does not come in contact with moving parts or sharp edges.
BLOWER
MOTOR
UTILITY
BOX
GROUND
LINE
GROUND LEAD
A91151
Fig. 37—Wiring Schematic
PULLEY AND BELTS Check belt tension and pulley alignment. (See Fig. 38.) Belt
tension is adjusted by motor tailpiece bolt. A deflection of about 3/4 in. to 1 in. per foot of span should be obtained by pressing belt firmly. Lock adjusting bolt in position after adjustment is made. Align pulley grooves by locating motor pulley on motor shaft or by moving entire motor along motor mounting bracket. Adjust blower speed by loosening setscrew in outer (moveable) pulley face and turning this face (half or full turns) so that adjusting setscrew is positioned precisely over the flat on pulley hub. Speed is reduced by adjusting pulley faces so they are further apart; speed is increased with faces closer together. Check pulley setscrews and bolts.
Disconnect electrical power to all circuits before servicing unit. Failure to do so may result in personal injury from electrical shock or moving parts.
As with any mechanical equipment, personal injury can result from sharp metal edges. Be careful when removing parts.
RETURN-AIR FILTER To clean or replace air filter, remove screws and filter access door.
Slide out filter. For washable type filters, clean with hot soapy water. Rinse clean and let dry.
New filters are available from a local distributor. Place filter in slot with filter arrow facing direction of airflow. Replace filter access doors with screws previously removed.
Never operate unit without a filter or with filter access door removed. Damage to blower motor may result.
COIL, DRAIN PAN, AND CONDENSATE DRAIN
Disconnect electrical power before removing any access panels or electrical shock may result.
The coil is easily cleaned when dry. To check or clean coil, remove coil access panel. If coil is coated with dirt or lint, vacuum with a soft brush attachment.
Be careful not to bend fins. If coil is coated with oil or grease, it may be cleaned with mild detergent and water solution. Rinse coil with clean water. Be careful not to splash water on insulation or filter.
Check drain pan and condensate drain at same time cooling coil is checked. Clean drain pan and condensate drain by removing any foreign matter from pan. Check for rust and holes. Flush pan and drain tube with clear water. If drain is restricted, clean with high-pressure water. If this does not work, use a plumber’s snake or similar probe device. Repitch drain pan to promote proper drainage.
MUST BE PARALLEL FOR PROPER ALIGNMENT
3
⁄4″
BELT ADJUSTMENTPULLEY ALIGNMENT
Fig. 38—Checking Pulley Alignment and Tightness
FA4A, FB4A, FC4B, AND FX4A SMART HEAT
CIRCUIT BOARD FUNCTION AND TROUBLESHOOTING Step 1—PCB Component Layout, Description,
and Function
1′
NOTE: All voltages are AC unless otherwise specified.
1. The low-voltage terminal board is used to connect indoor thermostat to low, 24-v side of transformer and to serve as a junction between indoor thermostat and outdoor section.
a. R terminal is used to connect secondary side of transformer
to thermostat and outdoor unit. R is fused.
b. C terminal is used to connect transformer secondary
common for thermostat and outdoor unit.
A91150
c. Y terminal provides input signal from thermostat signaling
heat pump operation.
46
Page 47
CEPL130121-01
SEC2 SEC1
Z1
C4
C14
R39
C3
R38
R36
R37
C15
R22
CESS430121-01A
1
R28
R25
R24
R27
XFORM
T1
DUMMY
T2
240 VAC
T3
MOV1
R1
R30
R23
C6
1
LED1
®
C5
U1
JW6
U2
D2
D3
D1
D4
C
BECBECBE
Q2
Q3
P1
®
LR40061
F1
COMMON
FAN
240
VAC
DUMMY
HSCI
F2
FS1
R3
D5
Z5
C2
R8
C13 R21
R9 JW7 R20 C12 C10 R13
R19 R10
C9 C8
R16
R2
R5
R40
R18 R11
R41
C7
R15
R4
R14
R26
R29
JW5
K1
Q1
123
456
789
HI
LO
ST1
R
R7
R6
Z4
R12 C11
R17
Z3
C
Y G O
W2D
W 2T
Z2
JW8
W 3
Y o
AUX– AUX+
JW4
JW3
K2
JW1
JW2
LOW VOLTAGE TERMINAL BOARD
JW1 (CUT WHEN OUTDOOR THERMOSTAT IS USED)
JW2 (HIGH FAN ONLY WHEN CUT)
RECEPTACLE
CLIP JUMPER FOR
HIGH SPEED FAN ONLY
CES0130025 –
K3
Fig. 39—Smart Heat Printed-Circuit Board (PCB)
d. G terminal provides input signal from thermostat signaling
continuous fan operation.
e. O terminal provides input and junction terminal for revers-
ing valve signal.
f. W2D terminal provides input from outdoor unit (heat
pump) signaling control board that heat pump is in defrost.
g. W2T terminal provides input from thermostat signaling for
supplemental or emergency heat.
h. W3 terminal provides input from outdoor thermostat. W3
and W2T are factory connected by JW1. This input is used only if an outdoor thermostat is required by local codes.
i. Y
terminal provides output from control board to energize
o
outdoor unit (heat pump) contactor.
2. Jumper wires (JW1 and JW2). (See Fig. 39.) a. JW1 connects W2T to W3 to limit staging of electric heat
with use of an outdoor thermostat. See Table 10 for staging. Smart Heat PCB controls staging to the extent that this feature is unnecessary unless required by local codes or regulations.
b. Cutting JW2 sets Smart Heat PCB in efficiency mode.
With JW2 cut, there is no loss of performance due to reduced indoor blower speed when heat pump is operating near balance point. This jumper may need to be cut if selected cooling fan speed is the same as required mini­mum motor LO speed tap selection. With JW2 cut, fan terminal LO becomes a dummy terminal.
3. A fuse is used to protect low-voltage transformer and PCB.
4. AUX+ and AUX- are connections for air conditioning acces­sories (EAC, humidifier, etc.).
A94127
5. F1, F2, HI, and LO are connections for indoor fan.
6. The 9-pin receptacle connects heater package wiring harness.
7. SEC1 and SEC2 are used to connect secondary side of transformer to PCB. SEC1 is internally connected to equip­ment ground.
Step 2—Unit Functions
TRANSFORMER NOTE: Terminals T1, T2 (if used), and T3 are wired to primary
or high side of transformer. The 208-v terminal (or blue wire if transformer has primary leads) is used on T3 for 208-v applica­tions. The 230-v terminal (or red wire) is used on T3 for 230-v applications. T2 is a dummy terminal.
ELECTRIC HEAT NOTE: When troubleshooting elements, position thermostat to
emergency heat. Wait approximately 12 minutes after all thermo­stat delays for all elements to come on.
1. When thermostat calls for supplementary heat, a 24-v signal is sent to PCB through W2T. The PCB energizes first stage of electric heat.
2. The first 2 stages come on if W2T and Y are energized at the same time. After each 10 minutes W2T is energized, another stage of electric heat is energized.
3. As W2T is de-energized, electric heat stages down in 8 minute steps with the exception of first step. The first step will be on only half as long as it was prior to W2T de-energizing.
4. When W2T is energized by itself, JW1 is cut, and an outdoor thermostat is used and is open, staging is limited as in Table
10.
47
Page 48
HEATER PART NO.
KFAEH2201H10 or
KFCEH0101H10
KFAEH2301H15 or
KFCEH0201H15
KFAEH2401H20 or
KFCEH0301H20
Table 10—Electric Heater Stage Limiting
STAGES (KW OPERATING)
W2T Only (JW1 cut) W2T and W3
Heater Stage 1 2 3 4
10 kw Non-Fused 3 6 9 9
15 kw Fused 3 8 11 15
20 kw Fused 5 10 15 20
5. When both W3 and W2T are energized without JW1 being cut or with outdoor thermostat closed, system operation stages heat up to maximum level if signal is energized for proper amount of time.
6. If only W3 is energized (JW1 is cut), there is no effect on PCB. No heat is energized.
ACCESSORIES Terminals AUX+ and AUX- are energized with 24 vdc when fan
is energized. The accessory kit KFAIR0101ACR is used to connect an EAC or humidifier.
NOTE: Loads cannot be connected directly to AUX+ and AUX-. Use the specified kit only.
BLOWER
1. Blower On Delay—To optimize comfort, there is a 30-sec blower on delay in heat pump heating mode only.
2. Blower Off Delay—Smart Heat control uses a 60-sec off blower delay, as opposed to the standard 90-sec delay.
Step 3—Smart Heat Operation
COOLING The Smart Heat option controls cooling mode in same manner as
conventional heat pumps are controlled. The fan has a 90-sec delay off/on cycle down.
HEAT PUMP HEATING The Smart Heat option does not control heating in the conventional
method. The PCB energizes compressor 30 sec before indoor fan is energized. This allows indoor coil to heat up eliminating cold-blow on start-up.
Although PCB has provisions for an outdoor thermostat, it is not needed for staging. On cycle down, indoor fan remains on 60 sec to recover heat stored in indoor coil.
DEFROST The Smart Heat PCB stages the correct amount of supplemental
heat during defrost. If too much heat is added, system stays in defrost for completion of defrost cycle even though thermostat is satisfied. On next cycle, 1 less element is energized during next defrost period.
NOTE: If the signal from thermostat is interrupted (ie., thermo­stat is satisfied) while unit is in defrost mode, the defrost cycle will be completed before unit shuts down.
TROUBLESHOOTING PRINTED-CIRCUIT BOARD (DIAGNOSTIC LED)
The PCB of Smart Heat option heater package contains a micro­processor which controls fan operation, fan speed, outdoor unit, and heater elements. For troubleshooting, a service LED indicates condition of PCB. See Table 11 for LED flash codes.
Table 11—LED Codes for Smart Heat PCB
FLASH CONDITION INPUT SIGNALS SYSTEM OPERATION
No Light/Flash —
Steady Light — Board Failure
Steady Flash —
1 Flash Y only
2 Flashes Y and/or W2T
3 Flashes Y and/or W2T
4 Flashes Y and/or W2T 5 Flashes Y, O Cool Mode
6 Flashes Y, W2D, and/or W2T Defrost Mode 7 Flashes W2T Emergency Heat Mode
No Power or
Board Failure
Stand By Condition
or Fan Only
Heat Pump Only
Operating
Heat Pump Plus
1 Sequencer
Heat Pump Plus
2 Sequencers
Heat Pump Plus
3 Sequencers
Step 4—Electrical Operating Sequences and Troubleshooting NOTE: Refer to Table 12 for proper input and output voltages.
See Fig. 40 for Smart Heat Proper Wiring Diagram.
READY-TO-START In ready-to-start (standby) mode, LED on board indicates a steady
flash. In this mode, 24-v power should be available at control’s low
voltage terminal strip terminals R and C. If 24v is not present across R and C, check the following:
• Is low-voltage fuse on control board good?
• Are line voltage fuses FU1 and FU2 good?
• Is LED on control on steadily or not on at all? Both of these
indications signal a possible board failure.
• Is 208/230-v power available to control across pins 7 and 9
of 9-pin connector? Is connection to board tight? CONTINUOUS FAN On a call for continuous fan, thermostat provides a 24-v input
signal to G terminal on low-voltage terminal strip. Sensing this signal, the microprocessor energizes a relay on control to provide power to high-speed winding of fan motor, at 1. The fan continues to run until fan switch on thermostat is turned off.
During continuous fan operation with no call for heating or cooling, LED indicates a steady flash, the same indication seen when system is in standby.
The call for continuous fan operation signal can be checked by placing voltmeter leads across terminals G and C of control’s low-voltage terminal strip. If 24v is not seen across these termi­nals, check for the following:
• Is 24v available across R and C? If not, refer to Ready-To-
Start section for items to check if 24v is not available.
48
Page 49
Table 12—Troubleshooting Voltage Readings and Test Points
Input Voltages
LOCATION NORMAL READING PURPOSE
L1 and L2 208/230 vac Main power supply input to fan coil L3 and L4 208/230 vac Power to electric heaters 9-pin connector
7 and 9 T1 and T3 208/230 vac Power to transformer SEC1 and SEC2 24 vac Power from transformer secondary R and C 24 vac Power from transformer secondary G and C 24 vac Call for continuous fan signal from room thermostat Y and C 24 vac Call for heat/cool signal from room thermostat
O and C 24 vac W2T and C 24 vac Call for electric heat from room thermostat
W2D and C 24 vac Defrost initiation signal from heat pump
208/230 vac Power to smart control
Signal to energize reversing valve from room thermostat (cooling). Also present during defrost.
Output Voltages
LOCATION NORMAL READING PURPOSE
HI and F1 208/230 vac Power to blower motor (high speed) LO and F1 208/230 vac Power to blower motor (low speed) Y
and C 24 vac Power to energize contactor in heat pump (heat and cool modes)
o
9-pin connector 1 and 4
9-pin connector 2 and 4
9-pin connector 3 and 4
vac—volts AC vdc—volts DC
24 vdc
24 vdc Power to energize SEQ 2
24 vdc Power to energize SEQ 3
Power to energize SEQ 1 NOTE: Sequencers use DC voltage
• Is thermostat fan switch set for continuous operation?
Confirm fan operation. Voltage to operate fan can be confirmed by placing voltmeter leads across terminals F1 and HI on control. The reading should be 208/230v. If 208/230v is not observed, check the following:
• Is 208/230v available at pins 7 and 9 of 9-pin connector? Is
connection to board tight?
• Are line voltage fuses FU1 and FU2 good?
If 208/230v is available across terminals F1 and HI and fan does not operate, check the following:
• Is fan motor capacitor good?
• Is blower wheel jammed or loose? Are there any other
mechanical problems preventing fan operation? COOLING
On a call for cooling, room thermostat provides input signals to control board at terminals Y and O. The O signal is also available to heat pump to energize reversing valve.
When it receives both these signals, the microprocessor responds by providing a 24-v output signal at the Y
terminal. This output
o
signal energizes contactor in heat pump and starts compressor. There isa3to5secdelay in output of Y
signal.
o
The call for cooling signals can be confirmed by placing voltmeter leads across low-voltage terminals Y, O, Y
, and C. The reading
o
should be 24v. If 24v is not available, check the following:
• Is 24v available across R and C? See Ready-To-Start section
for items to check if 24v is not available.
• Is thermostat function switch set in COOL position with
thermostat calling for cooling? Assuming heat pump has power and is adequately charged, it
should be running at this time in cooling mode. Indoor fan should also be running at this time. If indoor fan is not running, refer to Continuous Fan section for items to check.
HEATING (COMPRESSOR ONLY) On a call for heat, room thermostat provides an input signal to
control board at terminal Y. This signal causes the microprocessor to provide a 24-v output signal at terminal Y in heat pump. There isa3to5secdelay in output of Y
to energize contactor
o
signal.
o
Thirty sec after Y is energized, control energizes fan motor. It may run on high or low speed, depending on its operation in previous cycle.
Compressor operation in current cycle is monitored by the smart control to determine whether a fan speed change is required for enhanced indoor comfort. The LED indicator on control signals 1 flash, indicating compressor operation only with no electric heat.
The call for heat signals can be confirmed by placing voltmeter leads across low-voltage terminals Y, Y
, and C. The readings
o
should be 24v. If 24v is not available, check the following:
• Is 24v available across R and C? See Ready-To-Start section
for items to check if 24v is not available.
• Is thermostat function switch set in HEAT position with
thermostat calling for heat? Assuming heat pump has power and is adequately charged, it
should be running at this time in heating mode. Indoor fan should also be running at this time. If indoor fan is not running, refer to Continuous Fan section for items to check. When room thermostat is satisfied, indoor fan continues to run an additional 60 sec to recover heat remaining in indoor coil.
49
Page 50
HEATING (COMPRESSOR AND ELECTRIC HEAT) If heat pump alone cannot satisfy heat requirements of structure,
room thermostat calls for additional heat by way of an input to W2 terminal of control. When this occurs, control begins sequencing on electric heaters by energizing the first sequencer/heat relay. Indoor fan should be running at this time.
The logic of control determines how much and how soon these additional stages are brought on. By observing LED status light, the number of operating stages of electric heat can be determined. The control also varies indoor fan speed depending on number of energized stages of heat. In general, the more stages of electric heat, the higher the fan speed.
There is no hard and fast rule for determining exactly when stages will be energized since microprocessor in the smart control constantly monitors duration of previous heating cycle, setting of room thermostat, and number of stages of heat needed in previous cycle to satisfy room thermostat. Rather than try to determine what should be operating when, service technicians should check LED status light to see how many stages of electric heat are energized at a given time and confirm operation of sequencer/relay using a voltmeter. If a quick check of all stages is desired, set room thermostat as high as it will go. With a constant signal on W2T terminal, sequencers/relays energize every 10 minutes until all heaters are on.
The previous paragraphs described how to check for low-voltage inputs to control by placing voltmeter leads across low-voltage terminal strip and checking for 24v. The call for electric heat can be confirmed by placing voltmeter leads across W2T and C.
To check for operation of sequencers/relays, check directly across appropriate coil for 24 volts DC.
NOTE: All sequencer/relay coils are powered by 24 volts DC. This voltage is generated internally by the smart control.
In this example, sequencer/relay 1 is being checked. The procedure is the same for all other sequencers/relays. If 24 volts DC is not observed, check the following:
• Is room thermostat calling for electric heat? This can be confirmed by checking for 24 volts AC between low-voltage terminal strip terminals W2T and C.
• Is LED flashing appropriate code for number of sequencers/relays energized? In this example, 2 flashes should be visible, indicating 1 sequencer/relay is energized. Indicator tells how many sequencers/relays are energized, but does not tell which ones are.
• Is 9-pin connector for heater package tightly secured to control board?
CHECKING SEQUENCER OPERATION To check for operation of power circuit of sequencer/relay, place
voltmeter leads across sequencer/relay terminal 4 of sequencer/relay 1 and terminal 4 of limit switch 3. The reading should be 208/230v, and heater should be energized.
If 208/230v is not observed at terminals specified, check the following:
• Are fuses FU3 and FU4 good?
• Is limit switch LS3 open? If so, check fan coil air filter or air distribution system for blocking or restriction that might reduce airflow and cause limit switch to open.
Operation of heaters can be confirmed further by using a clamp-on ammeter in circuit shown to verify current is flowing through heaters. Amperage readings will depend on size of heater. The procedure for checking other sequencers/relays in system is identical to that just described.
EMERGENCY HEAT Emergency heat mode requires that room thermostat be placed in
EMERGENCY HEAT position. This locks out and prevents operation of heat pump outdoor unit. In this mode, heat is provided exclusively by electrical heaters in fan coil.
In this mode, room thermostat, at 1, provides an emergency heat input signal to smart control at terminal W2T. If jumper JW1, at 2, has not been cut and an outdoor thermostat installed to control electric heat stages, that same input signal is applied to terminal W3. For this example, assume that jumper JW1 has not been cut.
Eventually, the total number of heaters is cycled on. In emergency heat mode, LED indicator signals 7 flashes.
The amount of emergency heat available depends on whether jumper JW1 is cut and the number of heating elements. Table 13 illustrates results under various conditions. The heaters cycle on two elements initially and an additional element every 5 minutes until maximum level is reached.
Table 13—Effect of JW1 on Emergency Heat
JW1 cut*
4 elements 3 elements
50% 66.7%
JW1 not cut
4 elements 3 elements
100% 100%
* Outdoor thermostat opens
With JW1 cut, an outdoor thermostat (if closed) could cycle on additional heaters and system would perform as if JW1 was not cut. In effect, closed outdoor thermostat replaces cut jumper.
DEFROST In defrost mode, LED indicator signals 6 flashes. Defrost is
initiated by heat pump and is signalled to smart control by an input to W2D terminal. During defrost, outdoor unit switches to cooling mode, making it necessary to cycle on electric heaters to temper indoor air.
If electric heaters were not energized prior to defrost, smart control energizes sufficient elements to temper air. If heaters were energized prior to defrost, additional heaters will be cycled on to provide additional heat.
A defrost initiation signal can be confirmed by attaching voltmeter leads across low-voltage terminals W2D and C. If 24v is not observed, check the following:
• Is 24v available across R and C? See Ready-To-Start section for items to check if 24v is not available.
• Is there continuity in thermostat leads between heat pump and smart control?
• Is defrost control in heat pump operating properly?
50
Page 51
→ PURON® (R-410A) QUICK REFERENCE GUIDE
FOR INSTALLERS AND TECHNICIANS
• Puron (R-410A) refrigerant operates at 50-70 percent higher pressures than R-22. Be sure that servicing equipment and replacement components are designed to operate with Puron (R-410A).
• Puron (R-410A) refrigerant cylinders are rose colored.
• Recovery cylinder service pressure rating must be 400 psig, DOT 4BA400 or DOT BW400.
• Puron (R-410A) systems should be charged with liquid refrig­erant.
• Use a commercial type metering device in the manifold hose.
• Manifold sets should be at least 750 psig high-side and 200 psig low-side with 520 psig low-side retard.
• Use hoses with 750 psig service pressure rating.
• Leak detectors should be designed to detect HFC refrigerant.
• Puron (R-410A), as other HFC’s, is only compatible with POE oils.
• Vacuum pumps will not remove moisture from oil.
• Do not use liquid-line filter driers with rated working pressures less than 600 psig.
• Do not install a suction-line filter drier in liquid line.
• POE oils absorb moisture rapidly. Do not expose oil to atmosphere.
• Wrap all filter driers and service valves with wet cloth when brazing.
• A liquid-line filter drier is required on every unit.
• Indoor unit is equipped with a TXV. Replacement TXV must be designed for Puron (R-410A).
• Do not use an R-22 TXV.
• Never open system to atmosphere while it is under a vacuum.
• When system must be opened for service, break vacuum with dry nitrogen and replace filter driers.
• Do not vent Puron (R-410A) into the atmosphere.
• Do not use capillary tube indoor coils.
• Observe all warnings, cautions and bold text.
51
Page 52
THIS COMPARTMENT MUST BE CLOSED EXCEPT FOR SERVICING
BLOWER MOTOR
ROTATION
SCHEMATIC DIAGRAM
FIELD POWER WIRING
SEE RATING PLATE
LS4
1
LS3
2
LS2
LS1
YEL
COM
3
4
YEL
XFORM
DUMMY
240 VAC
208V
TRAN
SEE NOTE #3
BRN
FOR VOLTS & HERTZ
HTR4
HTR3
HTR2
HTR1
T1
T2
T3
BLK
230V
RED
L1
L3
FU3
FU1
YEL
YEL
YEL
YEL
YEL
F1
COMM
FAN
DUMMY
F2
BRN BRN
CAP
YEL-COM
NOTES:
1. USE COPPER WIRE (75°C MIN) ONLY BETWEEN DISCONNECT SWITCH AND UNIT .
2. CONNECT LOW VOLTAGE WIRING AS SHOWN (24VAC).
3. CONNECT TRANSFORMER PRIMARY TO THE PROPER VOLTAGE TERMINAL
4. TO BE WIRED IN ACCORDANCE WITH NEC AND LOCAL CODES.
5. IF ANY OF THE ORIGINAL WIRE, AS SUPPLIED, MUST BE REPLACED, USE THE SAME OR EQUIVALENT TYPE WIRE.
6. REPLACE LOW VOLTAGE FUSE WITH NO GREATER THAN 5 AMP FUSE.
7. REFER TO THERMOSTAT INSTRUCTIONS FOR "E" JUMPER INSTALLATION.
8. DO NOT
HI
240 VAC
LO
RED-LO
FM
BLU-MED BLK-HI
GRN/YEL-GND
CONNECT THERMOSTAT "E" TO PCB "W3".
MINIMUM MOTOR LO SPEED TAP SELECTION
FAN COIL SIZE
MOTOR SPEED AT 20 KW
MED
033 038 048042036030
MED
LO LO
DISCONNECT PER NEC
SEE NOTE #1
SEQ 3
BLK
9
SEQ 1
BLK
3
SEQ 2
BLK
7
SEQ 2
BLK
5
PCB
F
SEC 1
SEC 2
LOLO
R
INDOOR THERMOSTAT
10
4
8
6
BLK
Y
C
YCR
CAP COMM F FW GND HPLV HTR LS
070060
LO LO
L2
L4
FU4
BLK
BLK
BLK
BLK
ORG
3
1
2
654
789
YEL
JW1
O
G
W2T
W2D
EW2OG
SEE NOTES #2, #7,AND #8
CAPACITOR COMMON LOW VOLT FUSE FAN MOTOR EQUIPMENT GROUND HEAT PUMP LOW VOLT HEATER LIMIT SWITCH
322251-101
REV. B
FU1
BLK
VIO
RED
Yo
W3
LEGEND
NOT SUITABLE FOR USE ON SYSTEMS EXCEEDING 150V TO GROUND
NE CONVIENT PAS AUX INSTA LLATIONS DE PLUS DE 150 V A LA TERRE
HTR1
LS1
SYSTEM TRANSFORMER: 40.0VA
FAN COIL/HEATER: 26.3VA
REMAINING VA AVAILABLE: 13.7VA
SEQ3
BLK
SEQ2
SEQ1
BRN
HPLV
LVTB
LEADS
Y
W2
O R C
LED LVTB SEQ TRAN XFORM
PCB
SEC 1
SEC 2 LED
321 654 987
GND
DIAGNOSTIC LIGHT LOW VOLT TERM BRD SEQUENCER TRANSFORMER PCB TRAN TERMINALS FIELD LOW VOLTAGE HPLV LEADS MARKED TERMINAL PCB JUMPER (JW) UNMARKED TERMINAL
R
F
C G
O W2D W2T
W3
Yo
AUX -
AUX +
T1 T2
F1
T3
F2
GND RED-LOW
BLU-MED BLK-HI
GRN/YEL-GND
FAN MOTOR THERMALLY PROTECTED
CAUTION:
ATTENTION:
COMPONENT ARRANGEMENT
HTR4
RED 24 V
BRN
SEQ3
8
6
SEQ2
4
SEQ1
FM
LS2
BRN BRN
YEL-COM
NO POWER OR
BOARD FAILURE
BOARD FAILURE
STAND BY CONDITION
ONLY OPERATING HEAT PUMP PLUS
HEAT PUMP PLUS HEAT PUMP PLUS
COOL MODE DEFROST MODE
EMERGENCY HEAT
LS3/4
Y
910
JW1
7
JW2
5
HI
3
LO
LED FLASH CODES
NO LIGHT OR FLASH STEADY LIGHT STEADY FLASH 1 FLASH 2 FLASHES 3 FLASHES 4 FLASHES 5 FLASHES 6 FLASHES 7 FLASHES
HTR2HTR3
COM
TRAN
208 V 230 V
FU4 60A
L4
FU2 60A
L2 L1
FU1 60A
L3
FU3 60A
CAP
OR FAN ONLY
HEAT PUMP HEAT
1 SEQUENCER 2 SEQUENCERS 3 SEQUENCERS
MODE
Fig. 40—Smart Heat Typical Wiring Diagram
Copyright 1999 CARRIER Corp. • 7310 W. Morris St. • Indianapolis, IN 46231 f5sm
Manufacturer reserves the right to discontinue, or change at any time, specifications or designs without notice and without incurring obligations.
Book 1 4 Tab 3d 2e
PC 101 Catalog No. 03FA-4A3 Printed in U.S.A. Form F-5SM Pg 52 6-99 Replaces: F-4SM
A94132
(Motor Speed at 20kw Shown)
Loading...
Buy Points How it Works FAQ Contact Us Questions and Suggestions Privacy Policy Cookie Policy Terms of Use