I am working on a Coleman Presidential furnace. Model 7655-856. I can light pilot and then run furnace fine. When it reaches set point it will turn off flame and after a minute blower will shut down. Then pilot goes out. If I try to relight when I put the lighter in the hole it goes out immediately. If I jumper the blower and run it for a few seconds the pilot will relight again ok. It burns fine for a long while then I call for heat and the same scenario takes place. Do you have any ideas?
Heating & Cooling - Coleman
Answers & Comments
Keep updated after you check the flame and blow out burner with compressed air. if you require any further help in this issue.
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Make sure the flame is blue,and not yellow,or yellow in it,if there is blow it out with compressed air,the pilot light needs to be clean,If there is a new thermocouple in it,make sure the thermocouple is in the flame of the pilot light,also,look for a thermo limiter switch,some have it,some do not,it will be mounted on some metal where the heat will get to it,it is oval shaped ,with two screws mounting it,this can cause this problem also,if all this has been done,and checked,and does not help,replace the regulator.
Does the unit have a thermocouple? If so then I would suggest the replacement of the thermocouple. If not, then it sounds to me as if you are losing power to the gas valve once the unit shuts off causing the pilot to go out. Chek voltage at gas valve when you call for heat and see if you lose voltage to gas valve. If so, then the problem is before the gas valve maybe to a circut board if it does go to the circut board (if you have one on this particular unit) then I would think the gas control relay on the circut board is bad
Good luck will check back in a couple of hours to see if you got this answer and to see if I can help any further
Dave