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poohbear2767

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

Pooh Bear
15 years ago

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

Comments (11)

  • mr_havac
    15 years ago

    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?

  • Pooh Bear
    Original Author
    15 years ago

    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

  • Pooh Bear
    Original Author
    15 years ago

    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

  • iggie
    15 years ago

    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.

  • Pooh Bear
    Original Author
    15 years ago

    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

  • zl700
    15 years ago

    Venter must start before anything will start to happen in sequence

  • Pooh Bear
    Original Author
    15 years ago

    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

  • iggie
    15 years ago

    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.

  • zl700
    15 years ago

    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.

  • Pooh Bear
    Original Author
    15 years ago

    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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