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  1. #1
    Join Date
    Oct 2009

    Comfortmaker furnace issue: advice on how to proceed?

    I am a homeowner having trouble with a Comfortmaker furnace, and I am not trying to repair it myself (so don't worry). But I do need some advice. I've been working with one HVAC repair firm, but they haven't been able to solve the problem.

    This is a two-stage Comfortmaker gas furnace. It's in the attic and installed lying on its side. The model number is: NTP6075GFB1. It is not a condensing unit.

    The problem only occurs intermittently - sometimes it will work fine for a day or two, and then the problem will continously occur for a half-day or so. Here's what I hear when the problem is occurring:
    - I raise the temp on the thermostat and it clicks on.
    - The draft fan starts running immediately.
    - The blowers never start blowing.
    - The draft fan shuts off after about 90 seconds.
    - It tries again and repeats that cycle about 5 minutes later.

    I've had several technicians from one firm come to my home over the last few weeks trying to solve the problem. First, they were certain it was the igniter. They replaced that, and it didn't solve the problem. Then they said it was the smart valve. Replacing that fixed it for a day or two, and then problem started again. They replaced that smart valve with another new one - worked for a day or two and problem started again. Replaced the igniter - worked for a day or two, then problem started again. They say they are stumped and are waiting for tech support to call them back. They don't think it's the board since the problem is occurring intermittently.

    Other info:
    I've been up there myself just to collect some info for them. When the draft fan comes on, I don't believe the pilot is igniting, but I'm not certain. I did smell a moderate (but not large) amount of gas when the furnace should have been firing up. After the 90 seconds, the furnace goes into a soft lockout and flashes a 6+1 code. Nothing on the sticker on the door talks about that code. The sticker mentions 6 as the soft lockout code. But the sticker starts with the heartbeat, then proceeds to 2 flashes and 3 flashes which are for low pressure switch stuck open or closed. There is no indication of what 1 flash might mean.

    I'm not sure how to proceed. These guys can't figure out what the problem is. They mention the board but don't seem at all certain that that's the problem. I ask what else might be the issue, since we now know it's not the igniter or the smart valve, and they don't have any ideas.

    Do I need to work with a different firm? Or does this sound just as unusual to you?

    Thanks for any assistance that you can provide. This has been going on for weeks, and it's driving my family and me crazy.

  2. #2
    Join Date
    May 2000
    Colorado flatland native
    I'd contact Comfortmaker and try and locate a rep. You may have the wrong co servicing the unit. Is there a Comfortmaker dealer near you???
    My doctor gave me six months to live, but when I couldn't pay the bill he gave me six months more.
    Walter Matthau

  3. #3
    Join Date
    Mar 2004
    SE Michigan
    I believe I know what the problem is but cannot give DIY advice. All I can say is that you need a good service tech and not a parts changer and that he or she should focus on the electrics (hint).
    To put the world in order, we must first put the nation in order; to put the nation in order, we must put the family in order; to put the family in order, we must cultivate our personal life; and to cultivate our personal life, we must first set our hearts right.
    -- Confucius

  4. #4
    Join Date
    Oct 2009
    Thanks. I'm no fool and have no intention of doing this myself. The technicians I've been using are licensed Comfortmaker dealers and are listed on Comfortmaker's website.

    I actually had another technician come by today (also listed on Comfortmaker's site). He asked if when I last replaced my air filter. I told him I regularly replace it and actually that I had recently upgraded to a more expense, better filtration one. He believes that was actually causing the unit to overheat. He thinks I may be fortunate that the only thing damaged by the heat was one of the diaphragms. He thinks the board is OK and will be replacing the diaphragm later this week. So I'll see if that solves the problem.

    Not sure if when you say "electrics" if you mean the board - but each of these guys seems to think it's OK.

    Keeping my fingers crossed...

  5. #5
    Join Date
    Sep 2005
    Atlanta GA area
    Problem is in the low voltage control circuits... I think you already have guessed that.

    Let the current tech do what he can. If it does not resolve the problem, contact the manufacturer and ask for support.

    Quality work at a fair price with excellent customer service!

    Romans Ch's 5-6-7-8

    2 Chronicles 7:14

  6. #6
    Join Date
    Oct 2009
    one word water

  7. #7
    Join Date
    Jun 2004
    Howell, Michigan
    Moved into residential

  8. #8
    Join Date
    Sep 2002
    Northeast Ohio
    Moisture (water) and low voltage circuit. They should figure it out.
    A good HVAC tech knows how, an educated HVAC tech knows why!


  9. #9
    Join Date
    Oct 2009

    Problem still continues...

    I appreciate the responses. I'm going to pass along the suggestions to check for low voltage and water.

    This whole thing is really driving me crazy. The second company from the Comfortmaker site came out yesterday and replaced the diaphragm (which they believed was damaged from overheating due to a higher-quality, higher-density air filter I was using). They were convinced that would solve the problem. The heat was working when they left. But it was warm in the house last night, so the heat didn't run. I tried the heat when I woke up this morning and the same problem occurred - I heard the draft fan kick on and then nothing else.

    Re: water... I will have them check for it. However, I have already asked about that. It's not a condensing unit. The attic is dry and sealed very well. So I'm not sure where moisture would appear from.

    The fact that this continues to be an intermittent problem is what makes it awful. If it was a low voltage issue, would that cause it to fail every time? Or could it actually be intermittent like this?

    Thanks again for any help you can provide!

  10. #10
    Join Date
    Oct 2009
    FYI - looks like replacing the board has solved the problem - thanks for all for the help

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