White Rodgers 50A55-3797 Installation Manual download pdf (Page 7)

Red LED

Flash Error/Condition Comments/Troubleshooting

Slow Flash Normal operation Normal – no Call for Heat

Fast Flash Normal operation Normal – Call for Heat

2 External lockout (exceeded 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. 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.

3 Pressure switch problem, vent on Inducer

problem

Check switch function, verify inducer is working correctly. Refer

to wiring diagram, terminals PS.

4 Open high temperature limit switch Verify continuity through limit switch circuit. Refer to wiring

diagram terminals, HLO.

5 Flame sensed with gas valve de-energized 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.

6 Reversed polarity Verify the control and furnace are properly grounded. Check

and reverse polarity (primary or secondary) if incorrect.

7 Gas valve circuit error Indicates the gas valve relay contacts on the ignition module is

not functioning properly. Replace the ignition module.

8 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 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.

Continuous

Control failure Replace IFC

Off Control failure Verify power to the control

TROUBLESHOOTING

1 2 3 4 5 6 7 8

No comments

White Rodgers 50A55-3797 Installation Manual Page 7