I have a trane XL80 2 stage gas furnace, and when I turn the head on everything cycles, the ignitor comes on and then the gas valve opens and the burners ignite for a few seconds then shut off. The Flame sensor is new and local HVAC guys have tried 2 differnt control boards on it. They also replaced a limit switch. Any other ideas as to what might be causing this problem?
Make : Trane
Model : XL 80
There is something going on with the flame detection. was leads changed from flame rod and was flame rod flame signal checked with millivolt meter
yes they changed the flame rod and put a new wire on it as well and check the microamps
THe reading came back normal?
no it was low
Are control board grounded properly
Then flame has to adjusted to make it read with stronger signal, check gas pressure
yes, they tried the one that was on the Furnace after replacing the limit switch, and two others after that and they all did the same thing.
and they were all grounded properly
flame has to be adjusted with meter on to find proper reading
weak signal will not work
Flames all look good gas pressure is good, pilot on water heater right next to furnace is fine.
Flame rod may have to be bent into flame better
That was also tried
well I have no magic
request question closed and pleae don't accept
yeah the guys here were stumpped too, I just don't want to have to buy a new control board if its not the problem
just wanted a second opinion, I will accept you asked everything they did and that was without even seeing the unit. thats good enough for me
35 years experience, HVAC