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UPON INITIAL POWER UP, REMOVE ALL THERMOSTAT DEMANDS TO THE UNIT
PROBLEM: 1 UNIT FAILS TO OPERATE IN THE COOLING, HEATING, OR CONTINUOUS FAN MODE
Condition
Possible Cause
Corrective Action / Comments
1.1
- Both diagnostic lights fail to light
up.
1.1.1
Main voltage 120V not supplied to
unit.
ACTION 1 - Check 120V main voltage.
Determine cause of main power failure.
LED#1-Off
LED#2-Off
1.1.2
Miswiring of furnace or improper
connections.
ACTION 1 - Check for correct wiring of 120V
to power make up box and transformer.
ACTION 2 - Check 24V wiring to control
board.
# O
1.1.3
Circuit breaker tripped or fails to
close.
ACTION 1 - Replace circuit breaker if it is re-
set but does not have continuity.
ACTION 2 - If circuit breaker still trips, check
for short.
1.1.4
Door interlock switch failure.
ACTION 1 - Check that door switch is activated
when door is closed.
ACTION 2 - Check wire connections to switch,
replace loose connectors.
ACTION 3 - Check continuity of switch in
closed position. Replace if defective.
1.1.5
Transformer Failure.
ACTION 1 - Check that transformer output is
24V. Replace if defective.
1.1.6
Failed control board.
ACTION 1 - If all the above items have been
checked, replace board.
1.2
- Diagnostic lights flash the roll-out
code.
1.2.1
Roll-out switch open.
ACTION 1 - Manually reset the roll-out switch
by pushing the top button.
ACTION 2 - Determine the cause of the roll-
out switch activation before leaving furnace.
code.
LED#1 O
1.2.2
Roll-out switch failure.
ACTION 1 - Check continuity across roll-out
switch. Replace roll-out switch if switch is
reset but does not have continuity.
LED#1-On,
LED#2-Slow Flash
1.2.3
Mi
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ti
ACTION 1 - Check wiring connections to
LED#2 Slow Flash
Miswiring or improper connections
at roll-out switch.
ACTION 1 Check wiring connections to
switch.
1.2.4
Nine pin connector failure
ACTION 1 - Check 9-pin connector for proper
connection to control board.
ACTION 2 - Check continuity of the multi
plug pin.
1.3
- On initial power-up the comb. air
blower does not energize.
blower does not energize.
- Diagnostic lights flash the reverse
polarity code.
1.3.1
120V main power polarity reversed.
ACTION 1 - Check the 120V has line and neutral
correctly input into control.
ACTION 2 - Reverse the line and neutral at the
120V field connection.
LED#1-Fast Flash,
LED#2-Slow Flash.
120V field connection.
1.4
- On initial power up the combus-
tion air blower does not energize.
- Diagnostic lights flash normal
power on operation
1.4.1
Open combustion air blower motor
circuit.
ACTION 1 - Check for 120V to combustion air
blower. If no power, check wire and connec-
tions.
power on operation.
LED#1-Slow Flash
LED#2-Slow Flash
1.4.2
Failed combustion air blower mo-
tor.
ACTION 1 - If power is present at blower, re-
place blower.
