suburban SF heater 35k btu
for the last two seasons i have run into a few weird shut downs on the furnace
it will run and heat up but once the thermostats says to turn off, it does and then it stays off, until you turn off the heat at the thermostat
then it will re cycle and run fine for another year or so
it also makes tons of air noises versus actual air flow out the vents.
best way i found to get it out of lock out is to remove all power from the heater, then let is sit 10 minutes and bam is all good
so last night when it got to 20f it decided to act up again, so it got cold fast
after reading numerous manuals and some repair site i thank i found the solution.
apparently when the furnace runs for an extened period, like when its COLD as a freezer and the furnace cavity gets HOT the brain goes into lock out.
this morning i removed the stairs and the heater intake grill
and went to work ( with lots of help from the mrs.)
we vacumed and cleaned the dust, amd set out to better "air flow" in the heater chamber.
first off after cleaning, was the sealing of HOT air leaks, around vent hole pre-puncouts and the front cover.
I was very surpised at how much Hot blow by air (not exhaust gasses) was escaping the heat box and recycling back into the fresh air intake, plus heating up the wood flor and associated wiring.
after sealing up the leaks and tying back some close wires, the heater is quieter and has a better flow out the registers
took some afterward pics.
i used alum duct tape on the hot stuff
so far it has run perfectly this morning and afternoon with no more lock outs
Living in the Piney Woods of Texas.