Latest Discussions : HVAC

momskeeper

10:29AM | 11/11/04
Member Since: 11/10/04
1 lifetime posts
I have a 1995 modular home with a coleman evcon furnace..I had the control board and gas valve replaced last March, but am still having problems....The problem is once it reaches it's programmed temperature, then it will never kick on again until I manually lower the temp below the set temp and it will make a click and then I can manually raise the temp up to what I want it at and then it's the same process once it gets to the set temp. The thermostat will say it's 68 in here and the set temp is 71, but the furnace won't kick in. I noticed this a.m. that the furnace is flashing 4 times, and the book says "limit cycling, check return air filters". I took the filters out totally to test it and it does the same thing. I did look through the door while it was running and it was flashing 4 times so I took the door off and then the green light went to steady which means normal function....Is it not getting enough air and if not, what do I do about that?

Thanks! Kris

rayb64199

06:06AM | 01/16/05
Member Since: 01/15/05
1 lifetime posts
i know it says you have to leave the front cover on furnace but its the only way to keep it running, ive had the cover off for 2 years now

JGRIZZ

10:19AM | 01/17/05
Member Since: 12/16/04
54 lifetime posts
COuld be that the gas pressure is too high, what kind of fuel are u using and at what altitude are you? High gas pressure willc ause a high temperature rise through the furnace or perhaps the blower speed is set too low. You can manually try adjusting the gas pressure as a test by simply rotating the gas supply kok which is at the begginning of the flexible gas line where it enters the furnace. Typically it has a red or yellow handle. The valve should be in line with the pipe, by rotating the valve handle to a diagonal position you should reduce the gas pressure some. This may reduce the combustion chamber temperature. If it works you should have a service company come out and adjust your gas pressure and temperature rise to meet manufacturer specs.

Also be sure that all of your supply register diffusers are open, and you must be sure that the furance is the right size for your home, that looks like a 90,ooo btu furnace I would expect your home to be between 1700-22oo sqft.


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