Gas and Oil Home Heating Furnaces - Comfortmaker heats part of the time

We have a Comfortmaker RPJ II model # FC32A3XN1A. In the spring we had our usual guy come out and check out the ac and clean it. He discovered the control board was bad. I bought a new one for about a third of what the Air and Furnace company wanted to charge. It worked great for about a week, but for the last 3 days we've have a new problem. 5 times in the past 3 days, twice of which happened during the night, the air being blown out of the vents was cool instead of warm. If we turn it off for a while then turn it back on it usually comes out warm them. During the night it has dropped the temp in the house by almost 10 degrees before we woke up. Scary when we have 3 infants in the house. Any suggestions on what look for or what the problem may be? Thank you so much.

Melissa

I'm not familiar with that furnace but if it has a diagnostic light on the board, count the blinks then refer to the "blink code" either on the control or often on the inside of the blower door.

i'm not familiar with that furnace but if it has a diagnostic light on the board, count the blinks then refer to the "blink code" either on the control or often on the inside of the blower door.



agreed...............................................................

It does not have a light on it. Is there another way?

Yes, there is.


A furnace doesn't just "turn on." It goes through a series of steps in order to produce heat ---- the "sequence of operation."


You need to identify how far in that sequence you are getting.

Take the cover off the burner compartment so you can see the controls and such.

When the thermostat calls for heat, describe in detail what happens. You might need to do that several times in order to be able to appreciate what is happening.

There is probably no magic fix like just flipping a switch. Something is bad, will need to be tested, cleaned, or replaced.

If you are willing to stick it out with a back and forth dialogue, some of us I'm sure would be more than happy to help, and tell you what to look for in your furnace that can help us narrow things down - and how to test.

Pull the top door off . Set heat to come on. If you have plastic pipe leaving the furnace for exhaust then :

A small motor (inducer motor) should come on , a pressure switch a (round disk) (which may be sticking ) will close a circuit it is located near motor above with a small hose attached (could be loose , or cracked) . Then either you have a standing pilot (which stays lit all the time) or a intermediate spark (which will click numerous times) or a glo-stick (which will glo) . Then gas valve should open , gas will lite , fan will come on shortly thereafter . Do this when you have time (plenty). run the heat about 5 to 10 minutes . Repeat 5 to 10 times (crack a few windows if you need ) .Let us know what dont happen

Also go to end of plastis pipe check if air (warm when heat is on) is coming out.

Pull the top door off . Set heat to come on. If you have metal pipe leaving the furnace for exhaust then :

Then either you have a standing pilot (which stays lit all the time) or a intermediate spark (which will click numerous times) or a glo-stick (which will glo) . Then gas valve should open , gas will lite , fan will come on shortly thereafter . Do this when you have time (plenty). run the heat about 5 to 10 minutes . Repeat 5 to 10 times (crack a few windows if you need ) .Let us know what dont happen

If the metal pipe goes in chimney you may need to pull this out and check for blockage.

If any of these exhaust pipes has a box mounted on it outside it should which is a power venter it will have to be running from the time you turn the heat on till a lil after heat cuts off.