Coleman 7665-856 heat issues ??

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Coleman 7665-856 heat issues ??

Postby Diggerdan911 » Sat Sep 22, 2012 12:27 pm

Hey i need help ? i cannot for the life of me figure out why my furnace isnt working ?
its a Forced air gas furnace heres the deal stopped working before spring n forgot about it till now .. used ac all summer blower works fine T-stat is fine .. even replaced thermocouple .. still wont work pilot light is on stays on even before i changed thermocouple.. The burners dont ignite ? im kinda Stumped now ? can anyone give a hand or ideas to fix .. i dont have the money to call a tech in to deal with it thats why i been trying to figure out ?
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- Coleman 7665-856 heat issues ??

Postby Freon » Sun Sep 23, 2012 1:55 pm

Carefully check that the burners are clean and there are no spider webs or other possible obstructions to gas flowing from the burner.

Go to the furnace and have someone call for heat. Can you hear the gas valve open. It should be a distinctive metal sound. If you do not hear a metal clank, then while still calling for heat, make sure you have 24 volts AC at the gas valve. If you have 24 volts AC, then turn off the furnace and measure the gas valve solenoid for continuity. If no continuity then I think the gas valve may be the problem.

If you don't have 24 volts AC at the gas valve when calling for heat, check the various safety switches. Refer to the wiring diagram usually on the blower compartment door. You need to find why there's not 24 volts at the gas valve. Check that all wiring is securely fastened.
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