Heat pump on...no heat (Gas Heat)

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Old 10-16-04, 07:21 AM
anglophile
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Question Heat pump fan on but no heat

This morning when I turned my thermostat from 'off' to 'heat' for the first time this season, the fan came on fine but is pushing cool air.

It's a Carrier with electric AC and gas heat. The AC was working fine and my gas water heater is also.

Could it be an electrical problem? Or perhaps a thermostat malfunction?

Any suggestions on how to further diagnose this would be much appreciated!
 
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Old 10-16-04, 07:37 AM
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Hello: anglophile. Welcome to the Do It Yourself Web Site.

Your question was moved into the Heating Furnaces topic since the heating is done by gas and not electric. Even though the unit is a heat pump.

Several possibilities why no heat is present. Each brand and model uses a different type of ignition system. Knowing which type that unit has, (constant burning pilot or hot surface glow ignitor, pilot spark ingition, etc) helps to determine the likely problem cause and makes diagnostics easier.

Kindly use the reply button and post the model number, unit age and which type of ignition system is used to light the pilot. Unless the pilot is always on.

In this forum topic, heating furnaces, there are already many questions on furnaces with the same or like problems. Reading them will help determine the most likely cause, while waiting for the professionals to reply to your question. Also be glad to help you more myself...

If the ignition system is an HSI, (hot surface glow ignition) and the glow bar is not glowing, it may be burned out. If the ignition system is a pilot flame and you have to hold down a pilot lighting button to light a pilot, the element the pilot flame is heating is likely burner out.

Problem not as likely to be the T-Stat or an electrical current supply problem.
 
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Old 10-16-04, 07:56 AM
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Have to know for sure just what do you have there. Is it a heat pump for sure with gas furnace back up?? or just gas heat. If just gas heat what age is the furnace. Does pilot light , light or not?

ED
 
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Old 10-16-04, 09:17 AM
anglophile
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Thank you so much for attempting to assist! and sorry for posting in the wrong forum

Unfortunately my ignorance of heat pumps is profound and I can't offer much help. Ugh. I do know that it's a Carrier Weathertech sn: 48tmx036 301

I also don't know the age of the unit as I bought the house only last year. i can only hope that some info on it is in my papers from the purchase.

I am assuming that there is a self-lighting ignition system (or an always-on pilot) as I have never had to do anything other than switch the thermostat to 'heat'.

This problem began last season. It would blow cold air, I'd switch it off and back on and the air would turn warm.

Thank you guys again for any help
 
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Old 10-16-04, 09:44 AM
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Hello; Blue

The age of the unit might be able to be determined by the age of the house. May be the original equipment.

How old is the house???

You can turn the unit on and watch what happens at the unit. From that you can help us determine what needs to be known about the type of ignitor system it has.

Thus far, the questions still need to be known by the heating pros. Any detailed & specific info you can provide would be helpful and appreciated.

You can learn a lot about the unit by watching what happens when it is turned on, reading the mfg'ers label and providing us the answers to some questions about the unit.

Is there a gas pipe to the unit? May be a steel or iron pipe with or without a flex line going into the unit. You siad it is a gas unit but tell us how you know that? Use gas, (natural or propane) to other house appliances?

Water heater gas? Cooking stove and or oven gas? Dryer gas? Or electric to all others appliances and no gas to them? Propane tank outside?
 
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Old 10-16-04, 10:30 AM
anglophile
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Originally Posted by Sharp Advice
The age of the unit might be able to be determined by the age of the house. May be the original equipment.

How old is the house???

Is there a gas pipe to the unit? May be a steel or iron pipe with or without a flex line going into the unit. You siad it is a gas unit but tell us how you know that? Use gas, (natural or propane) to other house appliances?

Water heater gas? Cooking stove and or oven gas? Dryer gas? Or electric to all others appliances and no gas to them? Propane tank outside?
Lol, the house is 120 years old.

And I know it's gas because ... I pay the gas company a HUGE amount every winter!

Seriously, the HW and the heat are both natural gas (not propane - no tank - and yes, there's a line running to the unit). Everything else is electric.

You've been so patient! Thank you. Before I post again, I will a) take the panels off and observe what happens when it's started, and b) attempt to locate the papers (if any) that I have for the unit. That should help answer some questions.
 
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Old 10-16-04, 11:38 AM
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Hi: Blue

Up to this point we have accomplished much.

Unit cannot be the original if the house is 120 years old....
Must likely has an HSI (Hot Surface Ignition) system. Or unit has an electronic sparking system IID (Intermittent Ignition Device) to light a pilot flame.

We can further deduce that the HSI ignition system has a flame prover which might be failing or just dirty or a sparker not working or a pilot flame prover failing. Any of which can cause the heater not to fireup or remain fired up.

Fired up meaning the pilot flame prover fails and shuts the heater off. Or the burner flame sensor fails and shuts the unit off. May also indicate the HSI is not glowing hot enough to ignite the gas or the ignitor is not working at all.

Be aware that on most newer furnaces there is an interrupt switch likely to be a safety switch on the blower compartment door frame. The entire unit will not operate if the lower blower fan & filter access panel is not in place.

If that is the case, you can either leave that panel in place or hold the safety switch in using a finger. Releasing that switch will shut down the entire unit, if that switch happens to be installed on the model furnace.
 
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Old 10-16-04, 05:02 PM
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Still dont know if you have a heat pump with gas back up?

If you have a heat pump and its this warm outside just the heat pump should come on. When it gets cold out side then the outdoor tstat will turn the heat pump off and let the gas come on.
You said the fan came on did the outside unit come on??

ED
 
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