Troubleshooting - White Rodgers 50M56-743 Installation Instructions Manual

TROUBLESHOOTING

Red LED
Flash Error/Condition
1 External lockout
(exceeded retries)
2 Pressure switch stuck
closed
3 Pressure switch stuck
open
4 Open high temperature
limit switch
5 Flame sensed with gas
valve
de-energized
6 Open rollout switch
7 Low flame sense current
8 Ignitor relay fault
Rapid Flash Reversed polarity
Continuous On Normal operation
Off Control failure
White-Rodgers is a business
of Emerson Electric Co.
The Emerson logo is a
trademark and service mark
of Emerson Electric Co.
Comments/Troubleshooting
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.
Ignitor must be positioned to light the gas immediately when the valve
opens. If the ignitor has been replaced, verify hot spot position has not
changed.
Check sensor lead for shorting and verify furnace is grounded properly.
Verify gas supply to valve, gas valve in "On" position and appliance
lighting properly. Verify flame reaches flame sensor during ignition
attempts and gas pressures are correct.
Pressure switch stuck closed. Check switch function, verify inducer is
turning off. Refer to wiring diagram, terminals PSI / PSO.
Check pressure switch function and tubing. Verify inducer is turning on
and pulling sufficient vacuum to engage switch. Refer to wiring diagram,
terminals PSI / PSO.
Verify continuity through limit switch circuit. Refer to wiring diagram
terminals, HLI / HLO.
Verify the gas valve is operating and shutting down properly. Flame in
burner assembly should extinguish promptly at the end of the cycle. Check
orifices and gas pressure.
Verify continuity through rollout switch circuit. Refer to wiring diagram
terminals, RO IN / RO OUT.
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 or improve furnace and module ground. Verify sensor is located in
or very near flame as specified by the appliance manufacturer. Refer to
wiring diagram FS terminal and GND.
This flash code does not indicate a broken, disconnected or shorted
ignitor. It indicates the ignitor relay contacts on the ignition module are not
functioning properly. Replace the ignition module.
Verify the control and furnace are properly grounded. Check and reverse
polarity (primary or secondary) if incorrect.
No fault
Verify power to the control, replace control if power is at the control and no
lit Red LED
HOMEOWNER HELP LINE: 1-800-284-2925
www.white-rodgers.com
www.emersonclimate.com