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A/C but No Heat - TempStar - Ignitor Problem?

Posted by poohbear2767 (My Page) on
Wed, Oct 22, 08 at 15:07

At the end of last winter my central heat quit working.
The A/C worked just fine all summer. Just no heat.
It's starting to get cool weather so I need to fix this.

I pulled the panel off to inspect it. (power disconnected)
I cleaned all the cobwebs and other junk out of it.
I didn't see anything obviously wrong.
Turned the power back on and got my multimeter.
The unit gets 120vac on both lines coming in.
I unplugged the ignitor circuit from the control valve.
The ignitor circuit has continuity and the control valve
puts out 27volts to the ignitor circuit. (is that correct?)
That was all I could test. I put everything back like it was.
I don't want to just throw parts at it til it works.
So I am hoping y'all have some good advice for me.

TempStar PGF030K080/GPFM20K080 Installed in mid 2003.

Thanks for any help you can provide.

Pooh Bear


Follow-Up Postings:

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RE: A/C but No Heat - TempStar - Ignitor Problem?

No offense poohbear, but it sounds like your experience with this heating stuff is pretty limited and you've gone as far as you should. Call a service company, a gas furnace is nothing to be working on unless you know exactly how things should be in it. Isn't the safety of your property and family worth spending a few bucks?


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RE: A/C but No Heat - TempStar - Ignitor Problem?

I'm all for calling a service company if one is needed.
I have already taken the ignitor out and put it back in.
So if that is all it needs I feel I can do that.
My concern is if something further downstream is not working.
That would be the time to call in the professionals.
If the 27 volts I measured is normal then it probably just
needs an ignitor. If not normal then it needs a service call.
Unless there is something else that could be wrong that I'm missing.
I was hoping y'all could walk me thru troubleshooting this unit.

Thanks.

Pooh Bear


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RE: A/C but No Heat - TempStar - Ignitor Problem?

Lucky me. I found a webpage with extremely helpful info
about diagnosing this problem. Got lots to check out now.

Pooh Bear

Here is a link that might be useful: doityourself.com


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RE: A/C but No Heat - TempStar - Ignitor Problem?

Here,s something that might help a bit, before you go any further check your power vent switch. This is the switch connected via a hose to the housing on your vent damper fan. When the fan motor is activated the suction it generatesit activates this switch. If the line to this switch is plugged at any point the switch won,t make and the furnace wont fire. Turn off power and remove switch check make sure all openings are clear. Since you mentioned checking continuity, apparantly you have a vom or dvom, use this after you remove switch wires turn on power start furnace and check switch to see if it,s being activated. If it,s not clean all openings thoroughly, if switch still doesn,t make replace it. This will only take a few minutes and might save lots of frustration.


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RE: A/C but No Heat - TempStar - Ignitor Problem?

That is one of the first things I am going to check.
When I was checking it out a few days ago I noticed that
gas was not coming out of the pilot tube and the vent
fan wasn't coming on. I got the idea that the fan would
need to come on before the gas would flow and there would
have to be some kind of sensor to make sure it was on.
Now I know the sensor is probably just a vacuum switch.
It should be real easy to check that and power to the fan.
And I found out that 27 volts is the correct voltage AND
the expected life span of an ignitor is 3-5 years. Mine is
just over the 5 year mark and the site recommends keeping
a spare on hand anyway since Murphy's law says it will quit
working during the coldest week of the year and the service
guy won't have one in stock. Could take days to get one ordered.
So I am considering going ahead and changing the ignitor anyway.
I'll know a lot more when I do some tests this weekend.

Thanks.

Pooh Bear


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RE: A/C but No Heat - TempStar - Ignitor Problem?

Venter must start before anything will start to happen in sequence


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RE: A/C but No Heat - TempStar - Ignitor Problem?

Ok, I turned the thermostat to Heat and ran it up to 80 degrees.
The house is about 65 degrees so the furnace should kick on.
I went out to the unit and removed the access panel.
I unplugged the hose from the exaust blower assembly
and sucked a small vaccuum on the hose.
The pilot tube starting flowing gas, then the main burners came on.
But the exaust blower still wasn't running.
I checked power to the blower motor. 220volts.
It has two lines to it and both checked at 120 volts.
So power is getting to the motor but the blower isn't coming on.
I took the motor apart and found the problem.
The motor windings were burnt up. Also looks like a failed bearing.
I'm thinking the bearing failed and caused the motor to overheat.

So, I need a new furnace exaust blower motor.

I'll check online and make some calls tomorrow. (Monday)

Pooh Bear


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RE: A/C but No Heat - TempStar - Ignitor Problem?

Fasco makes replacements for these, you will have to buy a complete unit fan and all, motors are sold seperately. after you install fan be sure to oil it once or twice a year.


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RE: A/C but No Heat - TempStar - Ignitor Problem?

I have been looking online and I find the complete units
but I am not sure which model to get.
The access panel has this for a model #:
Model Number: PGF030K080E/GPFM20K080

Whoever install the unit put the manual inside the access panel.
What was left of the manual had this on the cover:
PGF, PGC, PGS, GPFM, GPCM
1.5 to 5 ton

It's a 1500 square foot house so probably a 3 ton unit?
The unit was installed in mid 2003.

I need to find a replacement blower. Cost is a factor.
I'll make some calls today, even to the installer.
But I'd like to find some online to compare rates with.

Thanks.

Pooh Bear


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RE: A/C but No Heat - TempStar - Ignitor Problem?

Getting scary
I thought you needed a combustion exhaust ventor, tonnage of a blower has no bearing on the part.

This is a packaged unit outside right?
(220v ventor, and pics shows side outlet, burners on top & ht exchanger off to side)

I believe you need a #1054268 (you won't find these items sold seperately, that is blower and motor, as someone stated earlier, too much liability and potential problems to install)

One size fits all, the amount of air drawn is controlled by a restrictor plate behind it.


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RE: A/C but No Heat - TempStar - Ignitor Problem?

I found the part. Draft Induction Blower With Motor.
I called a parts supply place over in Chattanooga
and they have one in stock, ~$143.00
They tagged it with my name and I pick it up tomorrow.
Should have everything up and running again by Wednesday afternoon.
I may put it back together tomorrow depending on what time we get home.

Thanks for all the help on this.

Pooh Bear


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