[WaldoLake]

I have a 1997 vintage Trane XE80, which would cycle on for heat, Gas burners will light but for only a second or two then go off. The unit has a White Rogers Model 50A50-471 controller, The controller is flashing error code 5: Flame Sensed with Gas Valve Off. After reviewing post on this forum I remove and cleaned the flame sensor, no change. I then changed out the flame sensor with one from a second furnace. Same results.

Does this mean the controller need to be changes?

Thanks,

 

[Tator1076]

You need to clean sensor . You maybe putting other units dirty flame sensor in there too,.

 

[WaldoLake]

Sensor has been cleaned. Other sensor was firing the other furnace.

 

[beenthere]

Sensor has been cleaned. Other sensor was firing the other furnace.

Its not the flame sensor. A dirty flame sensor won't give you a Flame detected with gas valve closed error. Since if its dirty, it generally can't detect a flame.

Either a reversed electrical polarity, poor ground, or the board is bad. Those would be the common problems for that error code when there is no flame.

 

[mmsall]

I'm having this same problem now. Were you able to fix yours? What ended up being the problem?

 

[jagans]

The controller board is held in with a few screws, in my case (carrier) one of those screws grounds the board to the frame of the furnace. Long use and the screw can back out a little, connection can corrode, No Ground. I would say loosen All screws a turn or two, spray with contact cleaner, and re tighten screws. By all screws I mean the thermostat leads too. Pull off the spades, spray, emory, spray, put back.

 

[WaldoLake]

Thanks, I'll check the ground on the controller, today

 

[jagans]

Thats a starting point, and a bad ground can really cause problems.