Bryant FA4A User Manual

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UTC TECH PUB

Service Manual

FAN COIL UNITS

F A X N o , 3 1 7 2 4 0 5 6 6 2

P . 0 0 1

; - IM'

■ S': ■ ■ Tis

■■■'-- ■ ■

f ABLE OF CONTENTS

... ■ -i'

SAFETY considerations.................................................................

iNTROPucTioi^ ....................................................^

UNIT irtENTIUCATiON

PRODUCT OFEERMG..........................................................................3

FAN MOTOR STEBfi TATS.........................

FA4A, FB4A, FC4B, AKD FH4A CIRCUIT BOARD

FUNCTIONJ^TROORLE^^ 3^6

■ Printed GirciiitBoifd jfPCB) CqmpijSntjjt ^Layout and Description

• Unit Functions ■_. ■ , fj I

• Troubleshooting PCB 'i; ''

ELECTRIC HEATER FUNCTION

AND TROUBLESHOOTiNG^„„„„;„,,........................................6-7

*-Description of Electric Heater Components

- Troubleshooting KFA and KFB Scries Electric Heaters FK4B FAN COIL DESCRIPTION

■ I ^'J'f AND TROUBLESHOOTING

• Integrated Controls and Motor (ICM2)

■ • PCB Layout and Description

• ,St(5iience of Operation

• Easy Select Configuration Taps ' : "

• Troubleshooting PCB " >

• Troubleshooting ICM2 ' ■ it'

■ Condensed Version of Troubleshooting Motor

. and Controls

• Accessories . , THERMOSTATIC EXPANSION VALVEis (TXV) ' Problems Affecting "DCV PISTON BODY CLEANING OR REPl^'CEMENT LIQUID TUBE STRAINER

coil/condensate fan removal

AND replacement....................................L.............................16-17

- A-Coil Units ‘ Slope Coil Units CARE AND MAINTENANCE

■ Filter Assembly.

• Cooling Coil, Drain Tan, and Condensate Drain

• Blower Motor and Wheel ■■iC ;

FFIA/FFIB SERVICE AND TROUBLESHOOTING

• Fan Motor ■

• Electric Heater Service

• Cleaning or Replafcmg Refrigerant Flow^Control Device

• Liquid Tube Strainer .■ iyi:.,.

' Sequence of Operation if 2

• Care and Maintenance

FD3A SERVICE AND TROUBLESHOOTING...........................21-23

• Fan Motor - ;

• Electric Heater Service

- Cleaning or Replacing Refrigerant Flow-Control Device

• Liquid Tube Strainer

• Care and Maintenance

FG3A SERVICE AND TROUBLESHOOTING...........................23-24

- Service

• Maintenance

........

..............

...................T.

.....................................................

...........................

.................

.................................... 17-lS

.................................

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18-21

7-lS

15-16

1-3

2-^

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FA^A, FB4A, AND FC4B SMART HEAT CIRCUIT BOARD

IhJNCTION AND TROUBLESHOOTING

• PCB Component Layout, Description, and Function

■ Unit Functions

• Smart Heat Operation

• Electrical Operating Sequences and Troubleshooting

, i SAFETY CONSIDERATIONS

Ij^proper installation, adjustment, alteration, service, maintenance, of use Can cause explosion, fire, electrical shock, or other conditions which may cause personal injury or property damage. CpnSult a qualiSed installer, service agency, or your distributor or blknch for information or assistance. The qualified installer or agency must use factory-authoriied kits or accessories when modifying thiS;pfoduct. Refer to the individual installation instruc tions packaged With the kits or accessories for detailed informa tion..

Follow all Safety codes. Wear safety glasses and work gloves. Use quenching cloth for bracing operations. Have fire extinguisher avmlable. Read these instructions thoroughly and follow all warnings or cautions attached to the unit. Consult local building m'dës and National Eectricai Code (NEC) for special installation requirements-

It is important to recognize safety information. This is the safety-alert symbol^j^ , When you sec this symbol on the unit or in instructions and manuals, be alert to the potential for personal injury.

Understand the signal words DANGER, WARNING, and CAU TION. These words are used with the safety-alert symbol, DANGER identifies the most serious hazards which will result in severe

^I3anc0ls; SM03-1

Fig. 1—Typical Fan Coll

...............................

SM03-2

1-1-95

A9£071

24-29

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2jitl- Position—Fan CoiF

A- RNC B-Standard C - Deluxe D - Furred in, Cased E - Furred in. Uncased'

F - Through Ihe Wall G- Commercfal H - Standard .Electric Fumaoe

J - Standard Hot Water .

K- ICM Motor, High EffTciericy

V - VariabJe Speed ^

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MObÈL UNIT SIZE DESCRIPTION CABINET

FA4ANF 01S-060 FB4ANB 042-070 Multtpoise Modular FB4ANF 016-060 Multipoise Single Piece

FB4ASB 042-060

FB4ASF 010-060

FC4BNB 042-070 Multipoise Modular FC4BNF 024-060 FD3ANA 018-030 Horizontal Single Piece

FF1A/FF1BNA 010-030 Vortical

FG3ANA 024, 036, 048, 060 Horizontal/Small Commercial Single Piece FH4ANB FH4ANF 001-004 Multipoles Single Piece FK4BNri 005, 006 Multipoise Modular FK4BNF 001-004 Multipolee

NOTE: Multipoise units are approved for upflow, doivnflow, and horizontal left and right applications.

UTC TECH PUB

table 1—product offering

003, 004 Multi poiss Modular

TABLE 2—FAN MOTOR SPEED TAPS

MODEL

FA4A 018-036 2 Black FA4A 042-060 3 Black Blue Red Yellow

FB4A 018-070 FC4B 024-070 3 Black Slue Red Yellow FD3A 016-030 2 Black — Red Yellow

FF1A/FF1B 018-030

FG3A 024, 036, 048, 060 1* FH4A G01-0D4 3 Black Blue Red Yellow

*Belt drive,

UNIT SIZE

NUMBER OF

SPEEDS

3 Black Blue Red Yellow

personal injury or death. WARNING signifies hazards which could result in personal ityury or death. CAUTION is used to identify unsafe practices which would result in minor personal

injury or product and property damage.

INTRODUCTION

The "F" Scries fan coil units arc designed for flexibility in a variety of applications, meeting upflow, horizontal, or downflow require ments. Units are available in 1-1/2 through 5 ton nominal cooling capaddes. Factory-authorized, field-installed electric heater pack ages are available in 3 through 30 kilowatts.

WARNING: 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.

UNIT IDENTIFICATION

The 16 position numbering chart allows identification of all available fan coil units, (See Fig. 2.)

FA4A, FB4A, FC4B, AND FR4A CIRCUIT BOARD

FUNCTION AND TROUBLESHOOTING

This section of the service manual describes the CES0130003 PCB by examining the functional operation of the PCB compo nents.

I. PRINTED CIRCUIT BOARD (PCB) COMPONENT LAYOUT AND DESCRIPTION

Layout of the actual PCB is depicted in Fig. 3.

L The low-voltagc ¡stripped leads are used to connect the 24-v

side of transformer

to indoor thermostat and outdoor

section.

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Multipolar

Multlpolne

50 Hz

MuitipoiSQ

50 Hz

Multipoise

HIGH

SPEED

Black

—

MEDIUM

SPEED

—

— — —

LOW

SPEED

'Blue

Red Violet

2. A 5-amp fuse is used to protect the low-voltagc 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 90

sec after G is dc-energiied.

II. UNIT FUNCTIONS

A- 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 (normallyopeij) terminal is wired to 2Q5V 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.

B. Indoor Fan

1. Wiring

Indoor fan motor yellow lead is wired to C terminal on transformer. The red, blue, or black speed lead is wired to 5PT 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.

Single Piece

Modular

Single Piece

COMMON

Yellow

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UTC TECH PUB

FIg. 3—Fan Còli

2. Functional Control a. Thermostat and Relay Control

When thermostat calls for the fan in cooling, heat pomp, heating, or fan-only mode, a 24-vdc signal is sent to relay. This causes the relay to close its nonnally-opcn 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 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-dosed 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;

C. Electric Heat

When thermostat calls for electric heat, a 24-vac signal is sent to PCB through WZ, causing first stage to turn on. W3 and E also receive signal if wired in with WZ. The signal sent to WZ causes J5r$t stage to turn on. If W3 and E arc not wired to W2, the sequencers can be controlled individually to stage additional electric heat. The sequence control is described in the following Section;

1. W2 When thermostat sends a signal to WZ, a Z4-vac signal is

applied across sequencer number f, causing it to close after a short delay. When sequencer number 1 closes, first stage of electric heal is energized. In straight electric heat, fan is

also energized through the nonnally-doscd 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 number 1 turns off and

sequencer opens after a delay of 60 to 90 sec. When sequencer 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-vaO Signal to sequencer

number 2 causes sequencer to dose, with Second stage of electric heat turning on after a short delay. The 24-vac

F A X N o , 3 1 7 2 4 0 5 6 6 2

PCB BLOCK WIRINS

LOW

VOLTAGE FUSE

Printed-Circuit Boafd , 2

-4-

signal applied to sequencer number iJ chuses fan -tb;opkate. Timing is Such that'sequchc'or liuinB'if FWiIf'iiirn:tii.h:'before sequencer number 2. Whem, sigriifl to'WS' is turned off,

sequencer number 2 op,ens;;^^aiter a short 'delay. tf^.W^Z is also satisfied, first stage of.,dectriC'heat and^-fimwiy ais^o tum off, providing thermostat is not calling for the fan.

3, E ■'

When thermostat ..sends, a signal :iDrB^ ' a' 24-v~ac signalris sent to sequencer number 3, The 24^Wc; sighhl' applied to

sequencer number 3 turns" on third'stagcof'clcctric heat. The 24-vac signal applied to sequencer number 1 turns on first stage of electric heat'arid fan. ’^hen 'thermostat stops calling for electric heat,' the signartO'Sequ£d£efs I, 2, and 3

are turned off/^ahd sequdhfcefs b'|fieh;'''Th'il5''caii&es''dw^ heat to turn off with fan providihg'lheriniti^Iat'i^'hdt calling for the fan, ^ ^ .

NOTE: Electric heaters are factory wired with alj stages tied

together. If independent staging is desired, cpnsul|, outdoor ther^ mostat Installation Instructions. ./

III. TROUBLESHOOTING PCB . ■ > 2

Use wiring schematic shown in Fig, 4 as a guide in troubleshooting PCB unless otherwise notedv ■ ■ —

A. If Fan Will Not tum On ffom TherWost^i: ' ^

IF THERE IS NO HIGH VOLTAGE TO PCB:

1. Check plug/receptacle connection. This supplies power from heaters to PCB. Be sure plug is connected properly.

, 2-, Check sequencer number X 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 Cl and L2. tf these are not receiving power, system cannot function.

IF PCB HAS HIGH VOLTAGE APPLIED TO IT;

1, Check low-voltagc 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 IS and 30 vac. If transfbmicr output is incorrect and transfonner is reqeiving 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.

A9434S

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) . 3 1 7 2 4 0 5 6 6 2

P ,

f THIS COMPARTMENT MUST BE CLOSEP EXCEPT TOR SERVICING

1 BLOWER MOTOR |

.„.J ROTATION

CboKW 1PH SCHEMATIC DIAGRAM)

NOT SUITABLE FOR Ü5É ON SYSTElilS EXCEEOINS leovTO GROUND

в 117

£0B/240VAC 24VAC 24VAC

3 11 7 U

LEGEND

U 3 2 8 1 4

ATTENTION:

MARKED TERMINAL PLUS AND RECEPTACLE

PflINTSD CIRCUIT BOARP

SEQUENCER TRANSFORMER UNMARKED TERMINAL RECEPTACLE

CIRCUIT BREAKER

Я p e 1 i

CAUTION: ^

USE COPPER WIRE (/S'C MIN) ONLY BETWEEN D[SCCNNECT 3WIT01 AND UNFT,

TO BE WIRED IN ACCORDANCE WITH NEC AND UDCALOODES, i, TRANSPORMER PRIMARY LEADS, BLUE 20aV, RED 230V. A IF ANY OFTHE ORIGINAL WIRE, AS 5UPPUED. MUST BE REPLACED,

USE THE SAME OR RQUIVACPJTTYPE WIRE.

REPLACE LOW VOLTAGE FUSE WITH NO GREATER THAN 5 AMP FUSE.

20KW HEATER USES ONE DOUSLg POLE LS ON MIDDLE TOP ELEMENT. 10, Й4 AND 30KW HEATERS USE СЮиВ1^ POLE UHIT SWITCHES. LARGEST HEATERS ARE SHOWN, SMALLER HEATSR5 Will HAVE FEWER ELEMENTS AND COMPONENTS. 1 PHASE HEATERS ARE SHOWN WIRED FOR 8INSL£ SUPPLY CIRCUIT.

10. USE SO AMP CLA38 К FUSSS ONLY. FOR REPLACEMENT.

11, (3) SPEED MOTOR SHOWN. OPTIONAL (2) SPEED MOTOR иЗЕЗШ(ВЦ^ AND LOW

(BLU OR RED). 13, CONNECT fi TO R, S TO G, ETC.. SEE OLnDOQR INSTRUCTION FOR DETAILS, la. IF WIRE CRIMP IS REMOVED AN EMEHOENCV HgATftgUY 16 REQUIRED.

(SEE OUTDOOR-THERMOSTAT (NSTRUCTIOMS)

3, Check low-voltage fuse shown in Fig. 3. Jf fuse is blown,

replace it. The transformer cannot supply power to board with fuse bjowfl or loose. If fuse blows when unit has pow‘er applied to it, the systejs most likely has 1 of the following problems:

a. Check all 24-v wiring for an electrical short. b. The maximum load on transfonner is 40 va. If load ott

transformer is excessive, the low-voltage 5-anjp 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.

32121A-101 REV. C

pig. 4—^Wiring Diagram

4. Check connections on primary side of transfonner. If they

■ 9 ■■ '■■ ■ 1

C, Check wiring of heaters. If a heater is miswired, fuse

arc not connected properly, the low-voltage terminal board cannot supply the 24-v signal to energize fan relay. If transfonner is receiving correct primary voltage hut is not

putting out correct secondary voltage, transformer needs to

be replaced.

2DB;S4aVAC J 24VAC 24VAC

may blow. If a heater is miswired, correct miswiring by comparing it to heater wiring label.

3^ 6

1 4

A9434G

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AÏÏG/14/2008/THÜ 03:46 PM UTC TECH PUB

FAX No. 317 240 5662

P. 006

fe. If Electric Hegt Stages Will Not Turn On But Fan Will

Turn On:

IF THERE IS NO HIGH VOLTAGE TO PCB:

1. Check plug connection between heaters and board. This supplies power to transformer and fan. 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 incoming high-voltage power leads, tf these arc not

receiving power, system c&undt function.

IF PCB 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), reifer to items 3 and 4 of previous If PCB 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 cither 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,

C, If PCB Fuse Keeps Blowing:

When loW“Voltage fuse blows, it means transformer would have blown if fuse had riot been in circuit to protect it. The fuse usually blows when there is a high Current draw on transformer, high voltage applied to low-voltagc 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 as shown in Fig. 4, Be sure transformer is not shorting out because thermostat wires arc miswired.

2. Check wiring of sequencers as shown in Fig. 4. Be sure low-voJtagc and high-voltage wiring is 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 spccifícationS-

D. If F^n Runs Continuously:

1. If PCB has no low-vohage power, check blue and black fan leads. These may be switched at sequencer,

2. If PCB has lowwoltage 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.

E- Transformer Failure:

1. Check 208-v and 230-v transformer connections. They may

be miswired.

ELECTRIC HEATER FUNCTION AND

TROUBLESHOOTING

This section describes KFA and KFB series electric heaters by examining the functional operation of these heaters,

I. DESCRIPTION OF ELECTRIC HEATER COMPONENTS

A. 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 clement radiant heat conditions. The devices arc sized to remain on-line under heat pump condi tions (11 ST air off coil) and minimum CFM;, but trip to prevent outlet air conditions above 200T or excessive component or duct temperatures.

The device itself consists of a bimetallic disc, which when overheated "snaps through" to open a normaliy-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.

If a limit switch has been determined to be défective, NEVER BYPASS THE LIMIT SWITCH. When replacing limit Switch, ensure that it is replaced with a limit switch of identical opening température and closing differential. Limits switches are typically

color coded to identify their range.

B. 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 (BTC), heat is supplied to a bimetallic disc which "snaps through" and closes switchTbe time required for PTC to heat to a suffiejeut point controls ON timing of device. The time required for disc to cool down when

power is removed controls OFF time of device. The PTC can be varied to provide varied timing. Typically a short ON equates to a long OFF,

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 arc different in each sequencer to provide a staged QN of a minimum of 10 sec between each sequencer — 3 stages of 2 elements since

the KFA and KFB Series .Деа1ег8 use , sequencers in which both switches of the 2-polc sequencer close simultaneously. Older models used sequencers which had a minimum delay of fO 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-

с. Positive Temperature Coefficient (PTC)

The PTC heater is essentially a resistor. It will operate on either AC or DC voltages. It should be noted that because resistance of PTC increases as, it, heats, initial current inrush is higher than its steady state condition.

II. TROUBLESHOOTING KFA AND KFB SERIES

electric heaters

A. Discolored Wire Insulation at Tormincl

Check quick-coimect terminal at discoloration. Connection may be loose, creating a high resistance through connection point.

B. 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.

C. No Heat

1, Check fuse for failure. If fuse has failed, refer to Fuse

Failure section.

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F A X N o , 3 1 7 2 4 0 6 6 6 2

2. Check for faulty transformer. Check output voltage of transformer secondary side R (red) and C (brown). Make sure output is between IS and 30 vac. If output voltage is

low pud input voltage teçtç normaJ, 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

V, replace Switch,

D. Heater Will Not Turn Off

1. Check low-voltage wiring for miswire.

2. Check for shorted elements to ground.

3. Replace sequencer contacts. They may be stuck closed.

E. Nuisance Trips

1. Check for low airflow due to dirty filters» blocked registers, Of Undersized duct.

2. Check blower motor and wheel for proper operation. Excessive current draw of motor will cause internal over load to trip.

3. The fan Speed may be low.

FK4B FAN COIL DESCRIPTION

AND TROUBLESHOOTING

The FK4B is similar to the discontinued FK4A only in that they both have 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

mainiain 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 ÏCM2 is pre-programmed and contains airflows for al) modes of operation. Blower characteristics (airflow, torque, and spccd-vs-static pres sure) are known from laboratory testing. If any 3 characteristics are known, the fourth iS defined.

Requested airflow is known because of Easy Select board con

figuration 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 0.6 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.

I. INTEGRATED CONTROLS AND MOTOR (ICM2)

The ICM2 is similar to the ICMI 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, (Sec Fig, 5.)

An ICM is first fed high voltage AC power through the 5-pin connector. The AC power is then rectiEcd to DC by a diode module. After rectification, DC signal is electronically communi

cated and fed in sequential order to 3 stator windings. The frequency of.communication pulses dctemiines 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-

II. PCB LAYOUT AND DESCRIPTION NOTE: Layout of actual PCB is depicted in Fig, 6 and 7,

The control is a single PCB which interfaces a variable-speed

ICM2 with Other System components. Power for system is supplied from a 230-vac^ 60-Hz line. Class 2 voltage (24 vac nom.), used for thermostat connections, is derived from a transformer located in close proximity to control. The primary and Secondary of transformer are connected to control board. The 24-vac secondary circuit includes a socket, soldered into circuit at SEC2, to receive a 5-amp automotive-type fuse. Connection to heater panel is made through 12-circuit connector

PI. 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

A. Electrical ConnectiDna

Eighteen 0,lS7-in quick-connect terminals arc used to provide programming selections for operating modes of ICM2. The 5 selection modes № 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)

III, SEQUENCE OF OPERATION A. Continuous Fan Mode

The thermostat closes circuit R to G, The G signal is sent directly to ICM2.

B. 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-spced high. The Y/Y2 signal is sent directly to 1CM2.

C. Cooling Mode—Two-Speed Low

Thermostat closes circuits R to Y1 and R to O (heat pump only). The Yl signal is sent directly to ICM2.

D. Electric Heat Heating Mode

Thermostat doses circuit R to W2, W3, or E,

The terminal block positions W2, W3, and E arc tied together by jumpers JWl and JW2, These jumpers are provided for field staging of electric heater banks through use of thermostats. When staging is a requirement, installer cuts jumpers and wires in thermostats as is the common practice with other fan coils. To ensure motor operation if any 1 of the inputs is energized^ the 3 electric heater inputs arc also interlocked through diodes Dl, D2^ and D3 to motor W input.

E. Heat Pump Heating Mode—Single Speed or 2-Speed High ■

Thcmiostai doses circuit R to Y/Y2 for single speed. A dreuit

from R to Yl is also required for 2-speed high. The Y/Y2 signal is sent directly to ICM2,

F. Heat Pump Heating Mode—Two-Speed Low

Thermostat doses R to Yl. The Yl signal is sent directly to ICM2.

G. Heat Pump Heating With Auxiliary Electric Heat

Thermostat doses circuits R to Y/Y2 and/or R to Yl with R to W2,

W3, Or E (and R to 0 in the case of defrost).

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 deEned as safe for operation of electric heater.

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UTC TECH PUB

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OPTIONAL SAFETY GROUND

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POWER CONNECTOR

CONTROL CONNECTOR

И. CFM Select Configuration Taps

The CTM Select taps are used by installer to configure system. The

ICM2 is capable of discerning wave shapes on some of its input?

and uses this capability to modify its operation to a pre

programmed table of airflows and can be modified in response to other inputs Such as the need for de-humidification.

I. 1CM2 Control Power

The ICM2 control power is supplied from R circuit through printed-circuit runs to motor control connector pin 6|, through rnotor control harness to motor. The C side of low-vpltagc control power circuit is connected by printed-circuit runs to motor connector pins 4 and 5, then through motor control harness to motor,

J. 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 SECl connected to metal standoff marked GROUND SCREW REQUIRED,

NOTE: A ground screw must be in place or erratic motor

operation can result.

K. 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 con-

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ICM2 Motor

nections Ml and M2 and transforníer power connections T1 and T3. Transformer connection T2 is a dummy terminal used for unused primary power lead. The transformer Secondary conriections are made at SECl and SEC2 connectors.

IV, EASY SELECT CONFIGURATION TAPS

The Easy Select taps are used by installer to configuire system. The ICM2 uses selected taps to modify its operation to a pre

programmed table of airflows. Airflows are based on system size

or mode of operatibh and thosd airflows arc modified in response to other inpüts stich as the need for de-humidifícation. (Sec Fig. 6.)

The FK4B Ran 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,

A. 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. The heater installed must fall within range selected for safe and continuous operation. It is appropriate to mention 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

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electric heaters are energized, the ICM3 will run the higher or heat pump efficiency airflow and electric heater airflow. The factory selection is largest heater range approved. (See Fig- 6-)

Fig, 6—Easy

B. AC/HP Size

The fectory 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. 6.)

C. 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, (Sec Fig, 6.)

D. 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/TO will regulate airflow supplied for all operational modes, except nonheat pump heating modes, +10 percent and -10 percent respec tively. The adjust selection options are provided to adjust airflow Supplied to meet individual installation needs for such things as noise, comfort, and humidity removal. (Sec Fig, ti,)

E. AC/HP Time Delay

Select desired time delay profile. Four motor operation delay profiles are provided to customize and enhance system operation, (See Fig. 6.) The selection options arc:

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AMP 12-PIN MATE-N-LOCK CONNECTOR (1)

Select Board

V. TROUBLESHOOTING PCB

Use Fig. 7 and S and Tables 3,4, and 5 as guides in troubleshoot ing PCB unless otherwise noted.

A. If Fan Wilt Not Turn On Ftom Thermostat:

IF THERE IS NO HIGH VOLTAGE TO PCB:

IF PCB HAS HIGH voltage APPLIED TO IT:

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1. The standard 90 sec off delay (factory setting).

2. No delay option used for servicing unit or when a thermo stat is utilized to perform delay functions.

3. A 30 sec on/90 see 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.

4. ENH, enhanced selection provides a 30 sec on/lfiO sec off delay at half airflow, adding comfort‘and efficiency.

1. Check connection of 12-pin plug from heaters to receptacle

On Easy Select board. This supplies power to PCB- Be Smre

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 LI and L2, If these arc not receiving

power. System cannot function.

1, Check low-voltage transformer leads (red and brown). Be

sure they are wired to correct locations, (Sec Fig. 6 and 8,)

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