Gas and Oil Home Heating Furnaces - Carrier furnace blowing cold air.
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SammyJay
12-21-08, 10:20 PM
Hey all, I'm new to these forums and hoping someone can help me here.
I have a Carrier natural gas furnace in my attic. Last winter was my first winter in this house and although I didn't want to use the gas furnace for cost reasons, I did want to get it set up as a backup heat source for the really cold nights if my electric space heaters couldn't cut it.
At first, the furnace didn't work, it turned out to be the thermo-coupler which is pretty standard stuff. I had a friend come over to change that out with a new one and get the pilot light lit. He told me before he left that I should mess with the thermostat to make sure it would kick on and off properly so I did. All was fine for about 15-20 minutes, after which the furnace began blowing out cold air.
I had my boyfriend go up in the attic to make sure the pilot light hadn't gone out and he verified that it was still lit. We shut off the gas at the main valve to the furnace and just left it.
This year I was hoping to get the furnace going again so I had someone come out to look at the furnace. (Not a professional service tech) He said everything looked okay with the furnace and said it was probably my thermostat. I bought a new thermostat and installed it. The furnace worked like a charm, kicking on and off fine and blowing warm air. It worked great for about 6 hours, but then began blowing cold air again.:wall:
The guy who suggested the thermostat said to turn the thermostat all the way up and kick the furnace on...if it blew out warm air then the problem was most likely the fan and limit switch. I tried this....but it still blew out cold air, even with the thermostat set to 95 (the max temp setting).
Another friend suggested it might be the regulator which would run me about $300...way more than I want to spend on this furnace which is not ancient but still several years old. Not to mention, it'll cost me $76/hour for a professional Carrier service tech to come out.
Any ideas what the problem might be? Is this something I can fix myself or will it require a service professional? If it will....I'll just have to shut off the gas to it and forget it.:helpme 2:
I have a Carrier natural gas furnace in my attic. Last winter was my first winter in this house and although I didn't want to use the gas furnace for cost reasons, I did want to get it set up as a backup heat source for the really cold nights if my electric space heaters couldn't cut it.
At first, the furnace didn't work, it turned out to be the thermo-coupler which is pretty standard stuff. I had a friend come over to change that out with a new one and get the pilot light lit. He told me before he left that I should mess with the thermostat to make sure it would kick on and off properly so I did. All was fine for about 15-20 minutes, after which the furnace began blowing out cold air.
I had my boyfriend go up in the attic to make sure the pilot light hadn't gone out and he verified that it was still lit. We shut off the gas at the main valve to the furnace and just left it.
This year I was hoping to get the furnace going again so I had someone come out to look at the furnace. (Not a professional service tech) He said everything looked okay with the furnace and said it was probably my thermostat. I bought a new thermostat and installed it. The furnace worked like a charm, kicking on and off fine and blowing warm air. It worked great for about 6 hours, but then began blowing cold air again.:wall:
The guy who suggested the thermostat said to turn the thermostat all the way up and kick the furnace on...if it blew out warm air then the problem was most likely the fan and limit switch. I tried this....but it still blew out cold air, even with the thermostat set to 95 (the max temp setting).
Another friend suggested it might be the regulator which would run me about $300...way more than I want to spend on this furnace which is not ancient but still several years old. Not to mention, it'll cost me $76/hour for a professional Carrier service tech to come out.
Any ideas what the problem might be? Is this something I can fix myself or will it require a service professional? If it will....I'll just have to shut off the gas to it and forget it.:helpme 2:
Pulpo
12-22-08, 05:38 PM
Troubleshooting Guide - Carrier (http://www.residential.carrier.com/support/troubleshooting.shtml)
That's the troubleshooting guide from Carrier. In your case the thermostat is good, the gas is igniting, the breakers are on, since the motor is running. Let's check the filter. What year was it last replaced?
That's the troubleshooting guide from Carrier. In your case the thermostat is good, the gas is igniting, the breakers are on, since the motor is running. Let's check the filter. What year was it last replaced?
SammyJay
12-22-08, 07:24 PM
Thanks for the reply Pulpo. I pulled the grate down off the intake and what do I find?? No filter at all. Makes me wonder if the previous owners ever bothered with them? Because if they had, surely there would have been an old one still in there.
So to answer your question, I have no idea how long it's been since the filter was changed since there wasn't one in there.
If something is clogged or dirty and is the reason for the furnace to work fine then suddenly blow cold air, what would it be and is it something I can clean myself?
So to answer your question, I have no idea how long it's been since the filter was changed since there wasn't one in there.
If something is clogged or dirty and is the reason for the furnace to work fine then suddenly blow cold air, what would it be and is it something I can clean myself?
Pulpo
12-22-08, 08:08 PM
The first thing I would do is install a filter and run the unit again. Besides keeping the air clean, it may be needed to regulate the air flow. If you're still getting cold air, remove the inspection cover, hold the safety button in by hand, the fan motor should start and the burner should light a few seconds after. If that isn't happening, the circuit board could be bad.