DIAGNOSTIC TABLE
Green
LED
Flash
Amber
LED
Flash
Red LED
Flash
Error/Condition
Comments/Troubleshooting
1
Flame sensed when no flame should
be present
Verify the gas valve is operating and shutting down properly. Flame in
burner assemble should extinguish promptly at the end of the cycle.
Check orifices and gas pressure.
2
Pressure switch stuck closed/ inducer
error
Pressure switch stuck closed. Check switch function, verify inducer is
turning off.
3
1st-stage pressure switch stuck
open/inducer error
Check pressure switch function and tubing. Verify inducer is turning on
the pulling sufficient vacuum to engage switch.
4
Open limit switch
Verify continuity through rollout switch circuit.
5
Open rollout/open fuse detect
Verify continuity through rollout switch circuit, check fuse.
6
1st-stage pressure switch cycle
lockout
if the first stage pressure switch cycles 5 times (open, closed) during
one call for heat from the thermostat the control will lockout. Check
pressure switch for fluttering, inconsistent closure or poor vacuum
pressure.
7
External lockout (retries)
Failure to sense flame is often caused by carbon deposits on the
flame sensor, a disconnected or shorted flame sensor lead or a poorly
grounded furnace. Carbon deposits can be cleaned with emery cloth.
Verify sensor is not contacting the burner and is located in a good
position to sense flame. Check sensor lead for shorting and verify
furnace is grounded properly.
8
External lockout (ignition recycles
exceeded where flame is established
and then lost)
Check items for exceeded retries listed above and verify valve is not
dropping out allowing flame to be established and then lost.
9
Grounding or Reversed polarity
Verify the control and furnace are properly grounded. Check and
reverse polarity (primary) if incorrect.
10
Module gas valve contacts energized
with no call for heat
Verify valve is not receiving voltage from a short. If a valve wiring is
correct and condition persists, replace module.
11
Limit switch open – possible blower
failure overheating limit
Possible blower failure, restricted air flow through appliance or
duct work. Verify continuity through limit switch circuit and correct
overheating cause.
12
Module Ignitor contact failure
Fault code indicates the module ignitor contacts are not functioning
properly. Replace module.
Solid
Module - internal fault condition
Module contacts for gas valve not operating or processor fault. Reset
control. if condition persists replace module.
Rapid
Twinning error
Check wire connections. If condition persists, replace module.
3
double
2nd-stage Pressure Switch Stuck
Open/Inducer Error
Check pressure switch function and tubing. Verify inducer is turning on
and pulling sufficient vacuum to engage switch.
1
Normal Operation with call for first
stage heat
Normal operation - first stage
2
Normal Operation with call for second
stage heat
Normal operation - first stage
3
W2 present with no W1
Second stage call for heat on thermostat circuit with no call for first
stage. Verify dip switches are set for two stage thermostat and check
thermostat first stage circuit. Configured for a multi-stage thermostat
the Module will not initiate heating unless first stage call from
thermostat is received.
4
Y present with no G call
Module will allow cooling to operate with only a "Y signal from the
thermostat but will also trigger this code. Verify thermostat is energizing
both "Y" and "G" on call for cool. Check "G" terminal connections.
Rapid
Low flame sense current
Low flame sense current is often caused by carbon deposits on the
flame sensor, a poorly grounded furnace or a mis-aligned flame sense
probe. Carbon deposits can be cleaned with emery cloth. Check for
improve furnace and module ground. Verify sensor is located in or very
near flame as specified by the appliance manufacturer.
1
Standby or Call for Cool
Normal operation. Waiting for call from thermostat or receiving
thermostat call for cool.
Solid
Standby
Rapid
Normal Operation with call for fan (G)
1
Normal Operation with call for Low
stage cool (YLO + G)
2
Normal Operation with call for
High stage cool/or single stage
cooling(YLO + G)
TROUBLESHOOTING
White-Rodgers is a business
of Emerson Electric Co.
The Emerson logo is a
trademark and service mark
of Emerson Electric Co.
www.white-rodgers.com
www.emersonclimate.com
