[flyinghighfurn]

My furnace flame goes out at times. Sometimes it won't light, other times it lights and quits after a few seconds or almost a minute. Then it might run for many minutes. One time I got a steady LED indicator light, controller needs replacement. Then it works again.

I have the White Rogers 50A50-471 controller. I can take the -473 controller out of a spare similar, but smaller, furnace. Are they directly interchangeable?

Also, I tried measuring the DC voltage out of the step down transformer but I can't get the meter to indicate any voltage. A quick tap across the terminals (with output leads removed) produced a spark. If I pull off an output lead while the furnace is running it immediately shuts down, so it must be supplying voltage.

Sorry for long question, cold in MN! Thanks!

[T-Top]

Make and model of the furnace will help. Your low voltage control circuit should be 24v ac not dc but yet I don't know what you have.

[flyinghighfurn]

Helping already! Yes, AC voltage, and it reads 24 volts correctly, silly me.

I have a Trane TUD100C936HO, 100,000 BTU input, house furnace. It's now been running for over 15 minutes this time, and continuing to run. Buy the way thanks so much.

[T-Top]

Helping already! Yes, AC voltage, and it reads 24 volts correctly, silly me.

I have a Trane TUD100C936HO, 100,000 BTU input, house furnace. It's now been running for over 15 minutes this time, and continuing to run. Buy the way thanks so much.

Yes the 473 will interchange with the 471. The new board for each part # is now 50a55-843. Make sure you have clean burners and flame sensor and check your pressure switch before spending the bucks on a control board. Good luck.

[flyinghighfurn]

Cleaned flame sensor, pressure switch checks out OK. Temp switches OK. When it cuts out the voltage to the gas valve drops out. So something is telling it to shut down. Now after shut down the controller board indicator light comes on steady after the failed restart. Will clean burners tomorrow. If that doesn't fix it I'll try swapping out the spare board. Thanks again very much.

[White Rodgers]

Hi. This is Aaron Moratalla from White Rodgers. Continuous LED on means Internal Control Failure. I suggest replace it with 50A55-843 or 50M56U-843. If you need more help, please don't hesitate to call our tech line at 800-284-2925. Thank you for choosing White Rodgers.