Armstrong World Industries HWC PREMIER 302, HWC PREMIER 123, HWC PREMIER 183, HWC PREMIER 243, HWC PREMIER 203, HWC PREMIER 182, HWC PREMIER 122, HWC PREMIER 242 User Manual
This manual presents information and guidelines for proper installation, adjustment, operation
and maintenance of Armstrong Magic-Pak HW/HWC Thru-the-Wall units. Read this manual
before attempting assembly, installation, start-up, adjustment or operation of the unit. If you have
any questions about the operation of the unit or a particular safety device, call or write Armstrong Air Conditioning Inc., 421 Monroe Street, Bellevue, Ohio USA 44811. Telephone: 419483-4840 Fax: 419-483-3557
The documentation and drawings contained in this manual are intended as a general guide, and
may not reflect exactly the current designs, or all of the options available to our customers.
Please call or write Armstrong Air Conditioning Inc. regarding specific details of a particular
furnace model, configuration or installation.
The information and specifications contained in this manual are subject to change without notice. Armstrong Air Conditioning Inc. reserves the right to change such specifications at any time
without incurring obligation. Every effort has been made to ensure the accuracy of the information in this manual. For the most current information, please contact the Ar mstrong Customer
Service Department.
This document is confidential. All information within is the sole property of Armstrong Air Conditioning Inc. and is loaned for mutual assistance. It may not be used for any purpose other than
originally intended, without prior written consent of Armstrong. It is not intended for use by
homeowners or as a guide for do-it-yourself projects. It provides specialized information for use
by qualified service personnel, who have the proper equipment, training and experience necessary to safely install, repair, adjust and maintain the Magic-Pak units and components described
within.
SRM-HW/HWC 8/99
Service Reference ManualTABLE OF CONTENTS
TABLE OF CONTENTS
1 - Specifications
2 - Sequence of Operations
3 - Unit Tear Down
4 - Component Location Illustrations
5 - Unit Components
6 - Installation
7 - Accessories
8 - Parts Lists
9 - Troubleshooting/Performance/
Charge Weights
Go to:If you need information on:
Section 1Perf ormance, electrical data and cabinet dimensions.
Section 2Sequence of operation descriptions with accompanying schematics.
Section 3Complete description of unit disassembly .
Section 4Locations of major components of HW/HWC models.
Section 5Illustrations and specifications for individual components including valv es ,
blowers, ignition controls and b lo wer control boards .
SRM-HW/HWC 8/99
Section 6Installation requirements and startup guidelines.
Section 7Complete listing of all Armstrong accessories available, including wall
sleeves, louvers and gas conversion kits.
Section 8Complete service parts lists for all HW and HWC models.
Section 9System check and troubleshooting procedures .
Service Reference ManualSPECIFICATIONS
Section 1 - Specifications
Models Covered By This Manual ............ 1-2
Model Number Guide ............................ 1-2
LINE VOLT A GE-FACTORY
LINE VOLTAGE-FA CTORYWHEN USED
LINE VOLTAGE-FIELD
LOWVOLTAGE-FACTORY
LOWVOLTAGE-FIELD
R
G
Y
W
NOTE:
IF ANY OF THE ORIGINAL
WIRES ARE REPLACED,THE
BLUE
YELLOW
RED
SAME SIZE AND TYPE WIRE
MUST BE USED.
CONNECTORCONNECTOR
BLOCKBLOCK
EVAP. MOTOR SPEED CONNECTIONSEVAP.MOTOR SPEED CONNECTIONS
JUMPER REQUIRED
*
R
G
Y
}
W
THERMOST AT
COOLINGCOOLINGHEATINGHEATINGMODELSMODELS
MED (BLUE)MED (BLUE)LOW (RED)26HWC12326HWC123
MED (BLUE)MED (BLUE)HIGH(BLACK)HIGH(BLACK)38HWC12338HWC123
LOW (RED)LOW (RED)LOW (RED)38HWC183
LOW (RED)LOW (RED)MED (BLUE)51HWC18351HWC183
LOW (RED)LOW (RED)HIGH(BLACK)HIGH(BLACK)64HWC18364HWC183
MED (BLUE)MED (BLUE)LOW (RED)38HWC24338HWC243
MED (BLUE)MED (BLUE)MED (BLUE)51HWC24351HWC243
MED (BLUE)MED (BLUE)HIGH(BLACK)HIGH(BLACK)64HWC24364HWC243
HIGH(BLACK)MED (BLUE)51HWC30351HWC303
HIGH(BLACK)HIGH(BLACK)HIGH(BLACK)64HWC30364HWC303
*
*
*
#45004-1
Note: On units that are equipped with a low ambient switch (designated
with an “SA” in the model number), sequence of oper ation during
cooling call is modified when outdoor temperatures fall below the
normal operating range. F or more inf ormation on the low ambient
switch equipped version of this unit, see the section beginning on
page 2-36.
FIGURE 2-1Connection Diagram
The following blower/ignition control board
DIAGNOSTICS
LED codes will indicate normal or abnormal
operations:
SLOW FLASH Normal Operation, No
FAST FLASH Normal Operation, Call for
2 FLASHSystem Lockout - Failed to
3 FLASHPressure Switch Open or
4 FLASHHigh Limit or Rollout
5 FLASHFlame Sensed and Gas
STEADYInternal Failure
Call for Heat
Heat
Detect or Sustain Flame
Closed
Switch Open
Valve Not Energized
(Micro-controlle r Failure;
Self-check)
SRM-HW/HWC 2/99
Service Reference ManualSEQUENCE OF OPERATIONS
Simplified Sequence - HWC123,183, 243, 303
Refer to Figure 2-1
2-5
•208/230V power is supplied to the junction box on
top of the unit
•24V power is supplied from the unit transformer to
the thermostat
CALL FOR HEAT
1. The thermostat closes the R-W circuit, sending a
24-volt signal to the unit.
2. The 24-volt signal energizes the combustion b low er,
causing the pressure switch to close.
3. The combustion blow er runs f or 30 seconds as a
pre-purge to trial for ignition.
4. The ignition control energizes the spark ignition and
opens the gas valve, causing the b urners to light.
When the gas valve energizes , a 30-second circulating air blower “on” dela y begins .
5. Flame sense is sent to the ignition control through
the flame sensor and flame sense wire.
6. After the 30-second delay, the circulating air blower
energizes and runs until the heat call is satisfied.
7. When the heat call is satisfied, the gas valve deenergizes. This shuts down the burners.
8. A 5-second combustion blow er post-purge dela y
and a 120-second circulating air blower “off” delay
start.
9. After the delay times elapse, the combustion b lo w er
and the circulating air blower stop .
CALL FOR COOLING
1. The thermostat energizes the R, Y and G circuit,
sending a 24-volt signal to the cooling contactor and
the ignition control to start the cooling sequence.
2. The contactor closes immediately, causing the
compressor and the condenser fan to run.
3. The 24-volt Y signal starts a 5-second circulating air
blower “on” delay .
4. After 5 seconds, the circulating air blower starts and
runs until the R, Y and G circuit is interrupted by the
thermostat.
5. When the R, Y and G circuit is interrupted, the
cooling contactor immediately de-energizes. This
causes the compressor and the condenser fan to
stop.
6. The ignition control starts a 90-second circulating
air blower “off” delay.
7. After 90 seconds, the circulating air blower stops .
FAN ON
1. The thermostat energizes the R-G circuit, causing
the circulating air blower to energize in cooling
speed.
2. The circulating air blower remains running in cooling
speed until the thermostat is switched to the “A UTO”
position.
FLAME SENSE
1. After the burners have been lit, the ignition control
starts a 10-second trial for ignition delay .
2. If after 10 seconds a flame has not been sensed by
the ignition control, the ignition control de-energizes
the gas valve and the spark ignitor .
3. The unit initiates three trials for ignition (flame
sense) before system lock out.
4. System lockout lasts 60 minutes or until po wer is
reset to unit (whichever comes first).
SRM-HW/HWC 2/99
Detailed Sequence follows
2-6
SPECIFICATIONSMagic-Pak: HW/HWC
Detailed Sequence - HWC123, 183, 243, 303
Refer to Figure 2-1
POWER
Line Voltage
With the unit at rest (no call from the thermostat), line
voltage will be present:
L1 Power
1. Through the L1 black lead to the L1 terminal on the
ignition control
2. At the L1contactor terminal
3. At the transformer terminal marked 208-240V
L2 Power
1. Through the L2 black lead to the induced draft
blower
2. At the L2contactor terminal
3. A transformer common terminal
4. At the T2contactor terminal
5. At the R terminal of the compressor
6. At the capacitor common terminals
Low Voltage (24 VAC)
With the unit at rest (no call from the thermostat), 24
volts A/C will be present:
control. This causes the combustion blower to
start by completing the line voltage circuit through
the L2 wire connection in the unit.
2. As the 24-volt signal is sent to pin 4 of the 6-pin
ignition wire harness by the ignition control, a 30-
second circulating air blower “on” dela y starts.
After the delay, the ignition control energizes the
heat speed blower relay. This sends L1 power to the
ACB HEAT terminal on the ignition control.
3. L1 power is then sent to the circulating air blowerterminal block where it is connected to the blower
motor. The circulating air blower starts by
completing the L1-L2 circuit through the L2 connection at the blower motor capacitor.
4. The combustion blower and the circulating airblower continue to run until the R-W circuit is
interrupted. After a 5-second post-purge dela y, the
CMB BLWR terminal on the ignition control deenergizes. This interrupts L1 pow er to the combus-
tion blower. After a 120-second circulating air
blower “off” delay, the ACB HEAT terminal de-energizes. This interrupts L1 to the circulating air
blower. As L1 pow er is interrupted, the blo wers
shut off.
Low Voltage
1. From the transformer 24V terminal to pin 4 of the
6-pin chassis low voltage harness
2. From pin 4 of the chassis low v oltage harness to the
24VAC hot terminal on the ignition control
3. From the 24VAC hot terminal to pin 5 of the 5-pin
thermostat harness (internal to board)
4. From the 24VAC hot terminal also to pin 6 of the 6-
pin ignition wire harness
5. From pin 6 of the ignition wire harness through the
auto reset limit switch and the manual reset
rollout switch to pin 1 of the 6-pin ignition wire
harness
Note: While the unit is at rest, the green LED shows
consistent slow flash. This indicates normal
operation - system at rest (standby mode).
CALL FOR HEAT
Line Voltage
The ignition control receives a signal from the R-W
circuit indicating a call for heat.
1. The combustion blower relay energizes, sending
L1 power to CMB BLWR terminal on the ignition
1. A call for heat closes the R-W circuit, sending a 24volt signal to the low v oltage white wire in the unit.
2. The 24-volt signal is received at pin 3 of the 5-pin
thermostat harness on the ignition control.
3. The 24-volt signal causes the combustion blower
relay to close, causing the combustion blower to
run. At this time, a 24-v olt signal is also sent out
through pin 2 of the 6-pin ignition wire harness.
4. The 24-volt signal from pin 2 of the 6-pin ignition
wire harness energizes one side of the Normally
Open pressure switch. As the induced draftblower reaches full speed, the pressure switch
closes and a 24-volt signal is sent to pin 5 of the 6pin ignition wire harness.
5. When the 24-volt signal is received at pin 5 of the 6pin ignition wire harness, the ignition control starts
a 30-second pre-purge delay.
6. After the 30-second pre-purge, the ignition control
initiates a trial for ignition. The spark ignitioncable terminal and pin 4 of the 6-pin ignition wire
harness energize simultaneously .
7. When the 24-volt signal is present at pin 4 of the 6pin ignition wire harness, the ignition control starts
a 30-second circulating air blower “on” delay.
8. The 24-volt signal from pin 4 of the 6-pin ignition
wire harness is received at the gas valve, causing
it to open and the burners to ignite.
SRM-HW/HWC 2/99
Service Reference ManualSEQUENCE OF OPERATIONS
9. After 30-second “on” delay, the circulating air
blower relay energizes the heat terminal and the
circulating air blower is energized.
10. The unit will continue to operate normally until the
R-W circuit is interrupted.
11. When the heat call is satisfied, the thermostat will
interrupt the R-W circuit. This causes the 24-volt
signal to the white wire in the unit to be de-energized.
12. The gas valve closes immediately as 24V through
pin 4 of the 6-pin ignition wire harness is deenergized by the ignition control.
13. The ignition control initiates a 120-second circu-
lating air blower “off” delay and 5-second com-
bustion blower post-purge delay.
14. After 5 seconds, the combustion blower shuts off.
15. After 120 seconds, the circulating air blower
shuts off and the system returns to standby mode.
Note: During a call for heat, the green LED shows
consistent fast flash (as long as the R-W circuit is
closed). When the R-W circuit is interrupted
(indicating the heat call has been satisfied), the
green LED returns to a consistent slow flash.
LIMIT/ROLLOUT OPENS
In all modes of operation, 24V AC is supplied to the
ignition control24VAC hot terminal and is passed
through the ignition control to pin 6 of the 6-pin
ignition wire harness.
1. A 24-volt signal is sent from pin 6 of the 6-pin
ignition wire harness to one side of the Normally
Closed manual reset rollout switch, across the
rollout switch to one side of the Normally Closed
auto reset limit switch and across the limit switch
to pin 1 of the 6-pin ignition wire harness.
2. This circuit energizes whenever line v oltage po wer
is supplied to the unit.
3. If the circuit is interrupted by either switch opening,
the 24-volt signal to pin 1 of the 6-pin ignition wire
harness de-energizes.
4. This causes the combustion blower relay to
energize, sending L1 power to the CMB BLWR
terminal on the ignition control. It also causes the
circulating air blower heat speed relay to energize, sending L1 power to the ACB HEAT terminal
on the ignition control. This causes both blowers
to start immediately.
5. The ignition control lockouts the spark ignitioncable terminal and pin 4 of the 6-pin ignition wire
harness until the 24-volt signal is restored at pin 1 of
the 6-pin ignition wire harness.
6. The circulating air blower and the combustionblower are energized until the 24-volt signal is
restored at pin 1 of the 6-pin ignition wire harness.
7. The green ignition control LED shows a 4 flash fault
code (indicating limit switch/rollout switch open).
8. When the 24-volt signal is restored at pin 1 of the 6pin ignition wire harness, the ignition control starts
a 5-second combustion blower post-purge delay
and a 120-second circulating air blower “off”
delay .
9. Once the delays hav e timed out, both b low ers stop
and the green LED flashes a consistent slow flash if
no heat call is present. (A consistent fast flash
appears if there is a call for heat.)
Note: The limit switch resets automatically when
temperatures are acceptable, b ut the rolloutswitch must be manually reset by pushing in on
the small button on top of the switch.
The reason why the switches opened must be
determined before any corrective action is taken.
PRESSURE SWITCH OPENS (BLOCKED FLUE)
When the R-W circuit is energized, a 24-volt signal is
sent to the ignition control. This starts the call for
heat.
1. The 24-volt signal from the R-W circuit energizes
the combustion blower relay, sending L1 power to
the CMB BLWR terminal on the ignition control.
This starts the ignition control.
2. At the same time the combustion blower relay
energizes, the 24-volt signal is sent to pin 2 of the 6pin ignition wire harness and from pin 2 to one side
of the Normally Open pressure switch.
3. When the combustion blower causes the pres-sure switch to close, a 24-volt signal is sent across
the switch to pin 5 of the 6-pin ignition wire harness.
The 24-volt signal energizes at pin 5 and the ignition
sequence continues.
4. If the combustion blower fails to close the pres-sure switch, the 24-volt signal is not sent to pin 5
of the 6-pin ignition wire harness and the ignitioncontrol does not initiate a 30-second pre-purge
delay.
5. No signal is sent to the spark ignition cable
terminal on the ignition control or to the gas valve
through pin 4 of the 6-pin ignition wire harness.
6. The combustion blower continues to run for 60
seconds. After 60 seconds, the ignition control
automatically de-energizes the combustion
blower relay. This interrupts L1 pow er to the CMB
BLWR terminal on the ignition control.
7. The combustion blower remains de-energized for
approximately six minutes. During this 6-minute
lockout, the green LED flashes three times (indicating pressure switch fault—open or closed).
2-7
SRM-HW/HWC 2/99
2-8
SPECIFICATIONSMagic-Pak: HW/HWC
8. The 24-volt signal will only be supplied to the limit
switch circuit through pin 6 of the 6-pin ignition wire
harness and to the pressure switch circuit through
pin 2 of the 6-pin ignition wire harness.
9. The system will repeat this sequence until the
pressure switch closes and the 24-v olt signal is
restored at pin 5 of the 6-pin ignition wire harness.
FAILED FLAME SENSE/TRIAL FOR IGNITION
When the pressure switch closes and a 24-v olt signal
is sent to pin 5 of the 6-pin ignition wire harness, the
spark ignition cable terminal and pin 4 of the 6-pin
ignition wire harness energize.
1. As spark voltage is supplied to the ignitor elec-trodes, the gas valve opens and this causes the
burners to ignite.
2. The ignition control continues to energize spark
voltage until a flame sense signal is supplied to the
flame terminal on the ignition control.
3. If a flame sense signal is not received at the flame
terminal on the ignition control, the spark igni-tion cable terminal remains energized for 10
seconds.
4. After the 10-second trial for ignition, the ignitioncontrol de-energizes the spark ignition cable
terminal and pin 4 of the 6-pin ignition wire harness.
This causes the gas valve to close and the electrode spark to stop.
5. Once the 24-volt signal is sent to pin 4 of the 6-pin
ignition wire harness, a 30-second circulating airblower “on” delay starts. After the dela y is timed
out, the circulating air blower starts.
6. After the spark ignition cable terminal de-energizes, the ignition control initiates a 30-second
combustion blower inter-purge delay.
7. After 30-second inter-purge, the ignition control
energizes the spark ignition cable terminal and
pin 4 of the 6-pin ignition wire harness. If the flame
sense signal is received at the flame terminal of the
ignition control, the unit continues heat call.
8. If the flame sense signal is not received, the system
goes through three trials following the abov e
sequence.
9. After three trials, the system goes into lockout and
only the high limit switch circuit and pressureswitch circuit remain energized during the 60minute lockout period.
10. If the flame sense is lost during the heat cycle, the
gas valve de-energizes immediately and the
system goes into the trial sequence.
CALL FOR COOLING
Line Voltage
1. L2 power passes through the fix ed closed L2-T2
terminals on the contactor to the RUN terminal of
the compressor and the COMMON terminal of the
capacitor.
2. L1 power is sent to the L1 terminal of the contactor.
When the Y signal energizes the contactor, the T2
terminal becomes energized. L1 pow er is sent to
the compressorCOMMON terminal and the
condenser fan. This energizes the compressor
and condenser fan motors.
3. When pin 1 (Y terminal) of the 5-pin thermostat
harness receives a 24-volt signal from the thermo-stat, a 5-second circulating air blower delay
starts.
4. After the 5-second delay, the ignition control
energizes the cooling speed relay. This sends L1
power to the ACB COOL terminal of the ignitioncontrol.
5. L1 power is sent to the circulating air blower
terminal block, energizing the circulating airblower motor.
6. When the R, Y and G circuit is interrupted by the
thermostat, the contactor is immediately de-
energized. This interrupts L1 power to the com-pressor and condenser fan motors, stopping
both.
7. The ignition control starts a 90-second circulat-
ing air blower “off” delay, after which the ACB
COOL terminal de-energizes. This interrupts L1
power to the circulating air blower motor, causing
it to stop.
Low Voltage
1. The thermostat energizes the R, Y and G circuit,
sending a 24-volt signal to the contactor coil and to
pin 1 of the 5-pin thermostat harness connected to
the ignition control.
2. The contactor closes immediately upon receiving
the 24-volt signal, causing the compressor and
condenser fan motors to start.
3. The 24-volt signal is also sent to pin 1 of the 5-pin
thermostat harness, initiating a 5-second circulat-ing air blower “on” delay.
4. After the 5-second delay, the ignition control
energizes the cooling speed relay and the circulat-ing air blower starts.
5. When the cooling call is satisfied, the thermostat
interrupts the R, Y and G circuit. The contactor
de-energizes immediately, causing the compressor
and the condenser fan to stop. The ignitioncontrol starts a 90-second circulating air blower
“off” delay.
SRM-HW/HWC 2/99
Service Reference ManualSEQUENCE OF OPERATIONS
6. After the 90-second delay, the ignition control deenergizes the cooling speed relay and the circulat-ing air blower stops.
FAN ON
1. When the thermostat is switched to the “FAN ON”
position, the R-G circuit sends a 24-volt signal to
pin 4 of the 5-pin thermostat harness.
2. The 24-volt signal energizes the cooling speed
relay, sending L1 power to the ACB COOL terminal
of the ignition control.
3. L1 power is sent to the circulating air blower
terminal block, causing the circulating air blower
to run in cooling speed.
4. The circulating air blower continues to run in
cooling speed until the thermostat is switched to
“AUT O”, interrupting the R-G circuit.
Note: With the thermostat in the “FAN ON” position
during heat call, ignition control will not energize
the heat speed relay. The circulating air blower
continues to run in cooling speed unless the limitswitch circuit opens, which would cause the heat
speed relay and the induced draft blower relay
to become energized. This would de-energize the
cooling speed relay until either the limit switch
circuit is closed or the thermostat is switched to
the “AUT O” position.
LINE VOLTAGE-FA CTORY
LINE VOLTAGE-FACTORYWHEN USED
LINE VOLTAGE-FIELD
LOWVOLTAGE-FACTOR Y
LOWVOLTAGE-FIELD
BLUE
YELLOW
R
G
Y
W
RED
NOTE:
IF ANY OF THE ORIGINAL
WIRES ARE REPLACED,THE
SAME SIZE AND TYPE WIRE
MUST BE USED.
CONNECTOR
BLOCK
R
G
Y
}
W
EVAP. MOTOR
EVAP. MOTOR
SPEED CONNECTIONS
SPEED CONNECTIONS
51HW
64HW
HEATINGHEATINGMODELS
LOW (RED)LOW (RED)26HW
HIGH (BLACK)38HW
MED (BLUE)
HIGH (BLACK)
THERMOST AT
SEE
CHART
FORWIRING
CAPACITORCAPACITOR
BLOWER
YELLOW
BROWN
BLOWER
MOTOR
BLACK
BLUE
RED
H
M
L
TERMINAL BLOCK
FIGURE 2-2Connection Diagram
#45008-2
The following blower/ignition control board
LED codes will indic a te n o rmal or abnormal
operations:
SLOW FLASH Normal Operation, No
FAS T F L A SH Normal Operation,Call for
2 FLASHSystem Lockout - Failed to
3 FLASHPressure Switch Open or
4 FLASHHigh Limit or Rollout
5 FLASHFlame Sensed and Gas
STEADYInternal Failure
DIAGNOSTICS
Call for Heat
Heat
Detect or Sustain Flame
Closed
Switch Open
Valve Not Energized
(Micro-controlle r Failure;
Self-check)
SRM-HW/HWC 2/99
Service Reference ManualSEQUENCE OF OPERATIONS
Simplified Sequence - HW (w/UTEC 1097 Board)
Refer to Figure 2-2
CALL FOR HEAT
1. The indoor thermostat energizes the R-W circuit,
sending a 24-volt signal to the ignition control.
2. The 24-volt signal causes the induced draft blo wer
to start, which closes the pressure switch.
3. Once the pressure switch closes, a 30-second
induced draft blower pre-purge starts.
4. After the 30-second induced draft blower pre-purge ,
the gas valve opens and the b urners ignite. This
starts a 30-second circulating air blower “on” dela y.
5. The unit continues to operate in the heat mode until
the indoor thermostat setting is reached. At that
time, the R-W circuit is interrupted.
6. The 24-volt signal to the ignition control is interrupted, causing the gas valve to close and the
burners to shut down.
7. A 5-second post-purge starts and following that the
induced draft blower stops .
8. A 120-second circulating air blower “off” delay
starts. After the elapsed time, the circulating air
blower stops .
2-11
FAN ON
1. When the thermostat is switched to the “FAN ON”
position, a 24-volt signal is sent to the ignition
control.
2. The ignition control immediately energizes the
cooling speed of the circulating air blower.
3. The circulating air blower runs in the cooling speed
until the thermostat fan switch is mov ed bac k to the
“AUT O” position. At this time, the circulating air
blower stops .
During the call for “FAN ON”, the circulating air blower
heat speed will not be energized by the ignition control
unless the limit switch circuit is interrupted.
SRM-HW/HWC 2/99
Detailed Sequence follows
2-12
SPECIFICATIONSMagic-Pak: HW/HWC
Detailed Sequence - HW (w/UTEC 1097 Board)
Refer to Figure 2-2
POWER
Line Voltage
With the unit at rest (no call from the thermostat), line
voltage will be present:
L1 Power
1. Through the L1 black lead to the L1 terminal on the
ignition control
2. At the transformer terminal marked 208-240V
L2 Power
1. Through the L2 black lead to the induced draft
blower
2. Transformer common terminal
3. At the circulating air blower capacitor terminal
Low Voltage (24 VAC)
With the unit at rest (no call from the thermostat), 24
volts A/C will be present:
1. At the transformer 24V terminal
2. At the 24VAC hot terminal on the ignition control
3. At pin 5 of the 5-pin thermostat harness (red wire
pin)
4. At pin 6 of the 6-pin ignition wire harness
5. Through the auto reset limit switch and the
manual reset rollout switch to pin 1 of the 6-pin
ignition wire harness
Note: While the unit is at rest, the green LED shows
consistent slow flash. This indicates normal
operation - system at rest (standby mode).
CALL FOR HEAT
Line Voltage
The ignition control receives a signal from the R-W
circuit indicating a call for heat.
1. The combustion blower relay energizes, sending
L1 power to CMB BLWR terminal on the ignition
control. This causes the combustion blower to
start.
2. As the 24-volt signal is sent to pin 4 of the 6-pin
ignition wire harness by the ignition control, a 30-
second circulating air blower “on” delay starts.
After the delay, the ignition control energizes the
heat speed blower rela y. This sends L1 power to
the ACB HEAT terminal on the ignition control.
3. L1 power is then sent to the circulating air blowerterminal block where it is connected to the blower
motor, starting the circulating air blower.
4. The combustion blower and the circulating airblower continue to run until the R-W circuit is
interrupted. After a 5-second post-purge dela y, the
CMB BLWR terminal on the ignition control deenergizes. This interrupts L1 pow er to the combus-
tion blower. After a 120-second circulating air
blower “off” delay, the ACB HEAT terminal de-energizes. This interrupts L1 to the circulating air
blower. As L1 pow er is interrupted, the blo wers
shut off.
Low Voltage
1. A call for heat closes the R-W circuit, sending a 24volt signal to the low v oltage white wire in the unit.
2. The 24-volt signal is received at pin 3 of the 5-pin
thermostat harness on the ignition control.
3. The 24-volt signal causes the combustion blower
relay to close, causing the combustion blower to
run. At this time, a 24-v olt signal is also sent out
through pin 2 of the 6-pin ignition wire harness.
4. The 24-volt signal from pin 2 of the 6-pin ignition
wire harness energizes one side of the Normally
Open pressure switch. As the induced draftblower reaches full speed, the pressure switch
closes and a 24-volt signal is sent to pin 5 of the 6pin ignition wire harness.
5. When the 24-volt signal is received at pin 5 of the 6pin ignition wire harness, the ignition control starts
a 30-second pre-purge delay.
6. After the 30-second pre-purge, the ignition control
initiates a trial for ignition. The spark ignitioncable terminal and pin 4 of the 6-pin ignition wire
harness energize simultaneously .
7. When the 24-volt signal is present at pin 4 of the 6pin ignition wire harness, the ignition control starts
a 30-second circulating air blower “on” delay.
8. The 24-volt signal from pin 4 of the 6-pin ignition
wire harness is received at the gas valve, causing
it to open and the burners to ignite.
9. After 30-second “on” delay, the circulating air
blower relay energizes the heat terminal and the
circulating air blower is energized.
10. The unit will continue to operate normally until the
R-W circuit is interrupted.
11. When the heat call is satisfied, the thermostat will
interrupt the R-W circuit. This causes the 24-volt
signal to the white wire in the unit to be de-energized.
SRM-HW/HWC 2/99
Service Reference ManualSEQUENCE OF OPERATIONS
12. The gas valve closes immediately as 24V through
pin 4 of the 6-pin ignition wire harness is deenergized by the ignition control.
13. The ignition control initiates a 120-second circu-
lating air blower “off” delay and 5-second com-
bustion blower post-purge delay.
14. After 5 seconds, the combustion blower shuts off.
15. After 120 seconds, the circulating air blower
shuts off and the system returns to standby mode.
9. Once the delays hav e timed out, both b low ers stop
and the green LED flashes a consistent slow flash if
no heat call is present. (A consistent fast flash
appears if there is a call for heat.)
Note: The limit switch resets automatically when
temperatures are acceptable, b ut the rolloutswitch must be manually reset by pushing in on
the small button on top of the switch.
2-13
Note: During a call for heat, the green LED shows
consistent fast flash (as long as the R-W circuit is
closed). When the R-W circuit is interrupted
(indicating the heat call has been satisfied), the
green LED returns to a consistent slow flash.
LIMIT/ROLLOUT OPENS
In all modes of operation, 24V AC is supplied to the
ignition control24VAC hot terminal and is passed
through the ignition control to pin 6 of the 6-pin
ignition wire harness.
1. A 24-volt signal is sent from pin 6 of the 6-pin
ignition wire harness to one side of the Normally
Closed manual reset rollout switch, across the
rollout switch to one side of the Normally Closed
auto reset limit switch and across the limit switch
to pin 1 of the 6-pin ignition wire harness.
2. This circuit energizes whenever line v oltage po wer
is supplied to the unit.
3. If the circuit is interrupted by either switch opening,
the 24-volt signal to pin 1 of the 6-pin ignition wire
harness de-energizes.
4. This causes the combustion blower relay to
energize, sending L1 power to the CMB BLWR
terminal on the ignition control. It also causes the
circulating air blower heat speed relay to energize, sending L1 power to the ACB HEAT terminal
on the ignition control. This causes both blowers
to start immediately.
5. The ignition control lockouts the spark ignitioncable terminal and pin 4 of the 6-pin ignition wire
harness until the 24-volt signal is restored at pin 1 of
the 6-pin ignition wire harness.
6. The circulating air blower and the combustionblower are energized until the 24-volt signal is
restored at pin 1 of the 6-pin ignition wire harness.
7. The green ignition control LED shows a 4 flash fault
code (indicating limit switch/rollout switch open).
8. When the 24-volt signal is restored at pin 1 of the 6pin ignition wire harness, the ignition control starts
a 5-second combustion blower post-purge delay
and a 120-second circulating air blower “off”
delay.
The reason why the switches opened must be
determined before any corrective action is taken.
PRESSURE SWITCH OPENS (BLOCKED FLUE)
When the R-W circuit is energized, a 24-volt signal is
sent to the ignition control. This starts the call for
heat.
1. The 24-volt signal from the R-W circuit energizes
the combustion blower relay, sending L1 power to
the CMB BLWR terminal on the ignition control.
This starts the ignition control.
2. At the same time the combustion blower relay
energizes, the 24-volt signal is sent to pin 2 of the 6pin ignition wire harness and from pin 2 to one side
of the Normally Open pressure switch.
3. If the combustion blower causes the pressureswitch to close, a 24-volt signal is sent across the
switch to pin 5 of the 6-pin ignition wire harness.
The 24-volt signal energizes at pin 5 and the ignition
sequence continues.
4. If the combustion blower fails to close the pres-sure switch, the 24-volt signal is not sent to pin 5
of the 6-pin ignition wire harness and the ignitioncontrol does not initiate a 30-second pre-purge
delay.
5. No signal is sent to the spark ignition cable
terminal on the ignition control or to the gas valve
through pin 4 of the 6-pin ignition wire harness.
6. The combustion blower continues to run for 60
seconds. After 60 seconds, the ignition control
automatically de-energizes the combustion
blower relay. This interrupts L1 pow er to the CMB
BLWR terminal on the ignition control.
7. The combustion blower remains de-energized for
approximately six minutes. During this 6-minute
lockout, the green LED flashes three times (indicating pressure switch fault—open or closed).
8. The 24-volt signal will only be supplied to the limitswitch circuit through pin 6 of the 6-pin ignition wire
harness and to the pressure switch circuit through
pin 2 of the 6-pin ignition wire harness.
9. The system will repeat this sequence until the
pressure switch closes and the 24-volt signal is
restored at pin 5 of the 6-pin ignition wire harness.
SRM-HW/HWC 2/99
2-14
SPECIFICATIONSMagic-Pak: HW/HWC
FAILED FLAME SENSE/TRIAL FOR IGNITION
When the pressure switch closes and a 24-v olt signal
is sent to pin 5 of the 6-pin ignition wire harness, the
spark ignition cable terminal and pin 4 of the 6-pin
ignition wire harness energize.
1. As spark voltage is supplied to the ignitor elec-trodes, the gas valve opens and this causes the
burners to ignite.
2. The ignition control continues to energize spark
voltage until a flame sense signal is supplied to the
flame terminal on the ignition control.
3. If a flame sense signal is not received at the flame
terminal on the ignition control, the spark igni-tion cable terminal remains energized for 10
seconds.
4. After the 10-second trial for ignition, the ignitioncontrol de-energizes the spark ignition cable
terminal and pin 4 of the 6-pin ignition wire harness.
This causes the gas valve to close and the electrode spark to stop.
5. Once the 24-volt signal is sent to pin 4 of the 6-pin
ignition wire harness, a 30-second circulating airblower “on” delay starts. After the dela y is timed
out, the circulating air blower starts.
6. After the spark ignition cable terminal de-energizes, the ignition control initiates a 30-second
combustion blower inter-purge delay.
7. After 30-second inter-purge, the ignition control
energizes the spark ignition cable terminal and
pin 4 of the 6-pin ignition wire harness. If the flame
sense signal is received at the flame terminal of the
ignition control, the unit continues heat call.
8. If the flame sense signal is not received, the system
goes through three trials following the abov e
sequence.
9. After three trials, the system goes into lockout and
only the limit switch circuit and pressure switch
circuit remain energized during the 60-minute
lockout period.
10. If the flame sense is lost during the heat cycle, the
gas valve de-energizes immediately and the
system goes into the trial sequence.
4. The circulating air blower continues to run in
cooling speed until the thermostat is switched to
“AUTO”, interrupting the R-G circuit.
Note: With the thermostat in the “FAN ON” position
during heat call, ignition control will not energize
the heat speed relay. The circulating air blower
continues to run in cooling speed unless the limitswitch circuit opens, which would cause the heat
speed relay and the induced draft blower relay
to become energized. This would de-energize the
cooling speed relay until either the limit switch
circuit is closed or the thermostat is switched to
the “AUT O” position.
FAN ON
1. When the thermostat is switched to the “FAN ON”
position, the R-G circuit sends a 24-volt signal to
pin 4 of the 5-pin thermostat harness.
2. The 24-volt signal energizes the cooling speed
relay, sending L1 power to the ACB COOL terminal
of the ignition control.
3. L1 power is sent to the circulating air blower
terminal block, causing the circulating air blower
to run in cooling speed.
IF ANY OF THE ORIGINAL
WIRES ARE REPLACED ,
THE SAME SIZE AND TYPE
WIRE MUST BE USED.
HEATING
LOW (RED)
HIGH (BLK)
LOW (RED) LOW (RE D )
MED (BLUE)
HIGH (BLK)
LOW (RED)
MED (BLUE)
HIGH (BLK)
MED (BLUE)
HIGH (BLK)
JUMPER REQUIRED
COOLING
MED (BLUE)
MED (BLUE)
LOW (RED)
LOW (RED)
MED (BLUE)
MED (BLUE)
MED (BLUE)
HIGH (BLK)
HIGH (BLK)
#39007D5
*
*
*
Note: On units that are equipped with a low ambient switch (designated with an “SA” in the model
number), sequence of operation during cooling call is modified when outdoor temperatures fall
below the normal operating range. F or more inf ormation on the low ambient s witch equipped
version of this unit, see the section beginning on page 2-38.
1. A call for heat closes the circuit between wires R
(red) and W (white) on the unit’s thermostat connections.
2. A low voltage (24 volts) signal is sent to the ignition
control, closing a relay which sends line voltage to
the induced draft blower. At the same time, a 24volt signal is also sent to the blow er control board.
This causes the blower control board to begin the
countdown to closing the relay that starts the
circulating air blower .
3. After the induced draft blower creates enough
negative pressure, the pressure s witch closes.
4. When the pressure switch closes, the 24-v olt signal
is sent to the ignition control. This starts a 30second pre-purge countdown, after which a trial for
ignition is made.
5. At the same time that the trial for ignition is made,
the gas valve energizes and gas flo ws to the
burners.
6. With the burners in operation, the trial for ignition
continues for se ven seconds. At the end of this
time, the ignition control stops sparking.
7. Approximately 30 seconds after the burners ignite,
the timer on the blower control board closes a rela y,
sending line voltage to and starting the circulating
air blower.
8. The unit continues to operate as long as there is a
24-volt signal between R and W. When the call f or
heat is satisfied, the 24-volt signal between R and W
discontinues. When W de-energizes, the pow er to
the induced draft blow er and the gas valve is
interrupted. The 24-volt signal to the blo wer control
board is also interrupted, causing the module to
start the countdown to blower “off” (approximately
90 seconds).
9. If at any time during a call for heat the limit switch
opens, the 24-volt signal to the white wire going to
terminal P.SW on the ignition control is interrupted.
This de-energizes the gas valve immediately. The
circulating air blower and the induced draft b lower
continue to run. When the unit cools down enough
for the limit switch to close , the 24-volt signal is
again sent to the P.SW terminal on the ignition
control. With terminal P.SW energized, the ignition
control again makes a trial for ignition and relights
the burners.
CALL FOR COOLING
1. A call for cooling closes the circuit from R to Y and
G.
2. A 24-volt signal is sent to blower control board
terminal G and to the compressor contactor. The
contactor closes, sending line voltage to the compressor and the outdoor condenser fan.
3. With a 24-volt signal at terminal G on the blower
control board, the circulating air blower starts in
cooling speed approximately 15 seconds later (or
immediately - see note below).
4. When the cooling call is completed, G and Y deenergize. The contactor opens immediately, stopping the compressor and the outdoor cooling fan.
When G de-energizes, the timer to turn off the
circulating air blower starts. The circulating air
blower turns off after 90 seconds (see note below).
FAN ON
1. When the thermostat switch is moved to the “FAN
ON” position, the circuit between R and G closes.
2. The 24-volt signal from G goes to the blo wer control
board which starts the timer.
3. Fifteen seconds after terminal G on the blower
control board energizes (or immediately after - see
note below), the circulating air blower starts.
4. When terminal G on the blower control board deenergizes, the timer to turn off the circulating air
blower starts. The circulating air blow er turns off
after 90 seconds (see note below).
Note: Heatcraft blow er control boards ha v e a G “on”
delay of 15 seconds and an “off” dela y of 90
seconds. Tridelta blower control boards have no
“on” time delay and a 60 -130 second “off” delay.
When the service disconnect switch is closed, power is
sent to the unit (unit in standby, no signal from the
thermostat). Power (208 - 230 v olts A/C) is supplied
to both black wires located in the junction block on top
of the unit.
Line voltage will be present at the follo wing locations:
First black wire
1. L-1 on the ignition control
2. L-1 on the contactor
3. L-1 on the blower control board
4. Terminal on the transformer marked 208V or
240V (whichever is being used)
Second black wire
1. Supplies power to the induced draft blower
2. L-2 on the contactor
3. Common terminal on the transformer
4. T-2 on the contactor
5. Red wire on the R terminal of the compressor
6. Red wire to the common terminals on the capaci-
tors
Low Voltage (24 VAC)
With the unit at rest (no call from the thermostat), 24
volts A/C will be found at these points:
1. Red wire exiting the top of the unit
2. Terminal marked 24 VAC on the ignition control
3. Terminal R on the blower control board
CALL FOR HEAT
Line Voltage
The thermostat closes the circuit between R and W.
The following is the sequence of operation f or the line
voltage side of the unit:
1. Terminal TH (24-volt) energizes on the ignitioncontrol, causing the relay in the ignition control
to close. This sends line voltage to the terminal
marked IND, causing the induced draft blower to
start.
2. When W energizes, a 24-v olt signal is also sent to
the W terminal on the blower control board. The
24-volt signal to the blower control board starts
the timer on the board. After 60 seconds , the heat
speed relay on the blower control board closes.
This sends line voltage from the terminal marked
HEAT to the circulating air blower, starting the
blower. The induced draft blower and the circu-lating air blower continue to operate until the heat
call is satisfied, interrupting the circuit between R
and W. The W terminal de-energizes, causing the
blower rela y to open appro ximately 90 seconds
later. This interrupts the line v oltage to the circulat-ing air blower and the blow er shuts do wn.
Low Voltage
1. A call for heat closes the circuit in the thermostat
between R and W, sending a 24-volt signal to the
white wire on the unit.
2. The white wire goes to the C terminal on the limit
switch, ignition control terminal TH and terminal
W on the blower control board.
3. When W energizes, the timer starts a countdown to
blower “on”. The blow er starts in approximately 60
seconds.
4. The 24-volt signal sent to terminal TH closes the
relay in the ignition control. This starts the
induced draft blower by energizing terminal IND
on the ignition control.
5. As the induced draft blower comes up to speed
and creates enough negative pressure, the pres-
sure switch closes. The 24-volt signal from the
pressure switch energizes terminal P.SW, causing
the ignition control to start a trial for ignition
(sparking).
6. As the trial for ignition starts, the V1 terminal on the
ignition control energizes. At the same time, a 24volt signal is sent to the gas valve, opening the
valve . The unit contin ues to operate as long as W is
energized.
7. When the call for heat is satisfied, the circuit between R and W is interrupted.
8. With W de-energized, the gas valve closes immediately and the induced draft blower shuts down
sever al seconds later .
9. The blower control board starts a countdown to
blower “off”. Appro ximately 90 seconds later, the
blower shuts do wn.
SRM-HW/HWC 2/99
Service Reference ManualSEQUENCE OF OPERATIONS
LIMIT OPENS
If the limit switch opens for an y reason during a call f or
heat, the following happens:
1. If the limit switch senses that the temperature in
the unit is too high, the contacts between terminals
C and NC on the limit switch open and the contacts between C and NO close. This interrupts the
24-volt signal to the pressure switch and also de-
energizes terminal P.SW on the ignition control.
The gas valve closes immediately, as the 24-volt
signal to terminal P.SW is no longer present. The
induced draft blower and the circulating air
blower continue to run. Power to blower control
board terminal W is maintained. The blowers
continue to run until the limit switch closes or the
heat call at the thermostat is satisfied.
2. When the limit switch senses that temperatures in
the unit are normal, the contacts between terminals
C and NO open, the contacts between terminals C
and NC close and operation of the unit returns to
normal.
PRESSURE SWITCH OPENS (BLOCKED FLUE)
1. If blockage of the flue occurs, the negativ e pressure
in the induced draft blower is reduced. At the set
point of the pressure switch, the contacts open.
This interrupts the 24-volt signal to terminal P.SW
on the ignition control. The gas valve closes
immediately, as the relay in the ignition control
opens and interrupts the signal to terminal V2 of the
ignition control.
2. Terminal W on the blower control board stays
energized and the circulating air blower continues to run. If the negativ e pressure is restored, the
pressure switch closes and sends a 24-v olt signal
to the P.SW terminal on the ignition control. Theignition control makes a trial for ignition again and
operation returns to normal.
2. The reason the rollout switch was tripped must be
determined before corrective action is taken.
3. The signal to terminal P.SW can only be restored if
the rollout switch is reset, which can only be done
manually. The W terminal on the blower control
board remains energized and the circulating air
blower continues to operate. Once the rollout
switch is reset, the operation of the unit returns to
normal.
CALL FOR COOLING
Line Voltage
On a call for cooling, the thermostat closes the circuit
between Y, G and R.
1. With Y energized, the contactor closes. This
sends line voltage to compressor terminal C,
causing the compressor to start. The outdoor fan
also starts, drawing air through the outdoor coil.
2. Terminal G on the blower control board also
energizes at the same time as Y. This starts the
timer on the blower control board. Approximately
15 seconds later (or immediately - see note on page
2-20), the terminal marked COOL energizes. This
sends line voltage to the circulating air blower,
starting the blower.
3. The unit continues cooling as long as both Y and G
are energized. When the cooling call is satisfied,
the circuit between Y, G and R is interrupted. The
contactor immediately opens, interrupting power to
the compressor and the outdoor cooling fan.
4. With the low voltage signal to terminal G on the
blower control board interrupted, the board starts
a countdown to blow er “off”. After appro ximately 90
seconds (see note on page 2-20), the cooling speed
relay opens and the circulating air blower shuts
down.
Low Voltage
2-19
Note: If the P.SW and TH terminals energize at the
same time, the ignition control will not respond.
A pressure switch being stuck closed is an
example of what would cause this to happen.
ROLLOUT SWITCH ACTIVATED
1. If the conditions in the burner compartment cause
the rollout switch to trip, the contacts on the switch
open, interrupting the 24-volt signal going to terminal P.SW on the ignition control. This causes theignition control to de-energize terminal V1,
interrupting the 24-volt signal to the gas valve and
immediately closing it.
SRM-HW/HWC 2/99
1. On a call for cooling, the thermostat closes the
circuit between R and terminals G and Y.
2. The 24-volt signal energizes terminal G on the
blower control board, starting the fan “on” timer.
Approximately 15 seconds later (or immediately see note on page 2-20), the relay closes. This
sends line voltage to the COOLING speed terminal
on the blower control board, which starts the
circulating air blower.
3. The signal from Y energizes the contactor, starting
the compressor and the outdoor cooling fan.
4. When the cooling call is satisfied, both G and Y are
de-energized. The contactor opens immediately,
causing the compressor and the outdoor coolingfan to stop.
2-20
SPECIFICATIONSMagic-Pak: HW/HWC
5. The circulating air blower shuts off approximately
90 seconds after G terminal on the blower controlboard is de-energized (see note below).
FAN ON
Low Voltage
1. When the switch on the thermostat is mov ed to the
“FAN ON” position, a 24-volt signal is sent to G.
2. With G energized, the blower control board starts
a countdown to fan “on”. After approximately 15
seconds, the fan starts (see note below).
3. The blower control board closes a relay on the
board, sending line voltage to the terminal marked
COOL on the board. This starts the circulating air
blower.
4. When the switch at the thermostat is mov ed to the
“OFF” position, the 24-volt signal to the blower
control board is interrupted. With no signal at the
G terminal, the blower control board starts a
countdown to fan “off”. Appro ximately 90 seconds
later, a relay on the blower control board opens
(see note below). This interrupts the power to and
stops the circulating air blower.
Note: Heatcraft blo wer control boards ha v e a G “on”
delay of 15 seconds and an “off” dela y of 90
seconds. Tridelta blow er control boards have no
“on” time delay and a 60 -130 second “off” delay.
SRM-HW/HWC 2/99
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