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  1. #1
    Join Date
    Jan 2020
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    New gas valve sticking immediately after replacing existing sticking gas valve

    Looking for a new set of eyes on this problem as I can't figure it out. I have a 2001 Coleman furnace recently converted to propane 3 years ago.

    We have had rare occasional problems with our furnace randomly having ignition errors (2 to 3 times a year). We would turn the thermostat off and on, call for heat, and it would start back up again. It was probably something I should have looked into more, but just never found the time.

    However, in October of 2019 the inducer fan went bad which also fried its relay on the motherboard. I replaced the inducer fan and motherboard. It all seemed to be working as good as before until December 2019 when the gas valve would not open up for ignition more times than not even though it would have 24 volts at the gas valve.

    Thus, I replaced the gas valve in December 2019. It fired up right away at first ignition and then refused to open up again until hours later attempts were successful. I measured 24 volts plus at the gas valve once the motherboard called for ignition, but the new gas valve still has intermittent ignition issues. I did notice that once the relay for the inducer fan kicks it on, the voltage at the gas valve goes from 1.3 volts to 13 volts before the call for ignition raises that voltage to 24 plus volts. My thought was that the new motherboard I replaced in October was bad with this much voltage being at the gas valve before the ignition call of 24 plus volts came. Perhaps this was locking up the gas valve somehow... I ordered another new motherboard from a different online supplier which looked more like my original motherboard. However, when it came in the mail it ended up being pretty much the same motherboard as the one I installed in October. I installed it yesterday and this 2nd new motherboard has 8.9 volts present at the gas valve when the inducer is running but before the ignition call. When the motherboard calls for ignition I get 24 plus volts and the gas valve worked all day yesterday. However, last night it had an ignition error again and the house was cold in the morning. I turned the thermostat on/off and the furnace fired right up this morning.

    What is going on here? I am at a loss. Another sticky gas valve which was just replaced in December? Is it another bad motherboard with these lower voltages being present at the gas valve before it raises to 24 volts during the ignition sequence? Have I switched some wires around during the motherboard installation that I haven't noticed? I took pictures before the replacement and everything seems to make sense. I also did replace the transformer at one point in time in all of this. The wires on the transformer just had the 24 volt side with yellow wires and the 120 volt side with black wires. Is there some sort of polarization of the wires that I need to worry about with this new transformer which could be causing all of these lower voltage occurrences? I have tried different combinations and it doesn't seem to be making a difference, but maybe I haven't explored this fully yet? Anyone have other ideas? Do I need to not buy my parts from these online suppliers which are supposedly new and look new? Should I just buy the more expensive parts from the local distributor (if I can get them to sell to me, a non licensed hvac person)? I have got quotes of prices but then get asked for my business name and hvac license number...

  2. #2
    Join Date
    Jun 2014
    Location
    Dover, DE
    Posts
    11,862
    Post Likes
    What’s your service technician suggest to fix the problem?
    I havent failed. Ive just found 10,000 ways that wont work. - Thomas Edison

    Its not whether you get knocked down, its whether you get up. - Vince Lombardi

    "In this house we obey the laws of thermodynamics" - Homer Simpson

    Local 486 Instructor & Service Technician

  3. #3
    Join Date
    Aug 2002
    Location
    Southold, NY
    Posts
    27,426
    Post Likes
    Quote Originally Posted by Homehvac9876 View Post
    Looking for a new set of eyes on this problem as I can't figure it out. I have a 2001 Coleman furnace recently converted to propane 3 years ago.

    We have had rare occasional problems with our furnace randomly having ignition errors (2 to 3 times a year). We would turn the thermostat off and on, call for heat, and it would start back up again. It was probably something I should have looked into more, but just never found the time.

    However, in October of 2019 the inducer fan went bad which also fried its relay on the motherboard. I replaced the inducer fan and motherboard. It all seemed to be working as good as before until December 2019 when the gas valve would not open up for ignition more times than not even though it would have 24 volts at the gas valve.

    Thus, I replaced the gas valve in December 2019. It fired up right away at first ignition and then refused to open up again until hours later attempts were successful. I measured 24 volts plus at the gas valve once the motherboard called for ignition, but the new gas valve still has intermittent ignition issues. I did notice that once the relay for the inducer fan kicks it on, the voltage at the gas valve goes from 1.3 volts to 13 volts before the call for ignition raises that voltage to 24 plus volts. My thought was that the new motherboard I replaced in October was bad with this much voltage being at the gas valve before the ignition call of 24 plus volts came. Perhaps this was locking up the gas valve somehow... I ordered another new motherboard from a different online supplier which looked more like my original motherboard. However, when it came in the mail it ended up being pretty much the same motherboard as the one I installed in October. I installed it yesterday and this 2nd new motherboard has 8.9 volts present at the gas valve when the inducer is running but before the ignition call. When the motherboard calls for ignition I get 24 plus volts and the gas valve worked all day yesterday. However, last night it had an ignition error again and the house was cold in the morning. I turned the thermostat on/off and the furnace fired right up this morning.

    What is going on here? I am at a loss. Another sticky gas valve which was just replaced in December? Is it another bad motherboard with these lower voltages being present at the gas valve before it raises to 24 volts during the ignition sequence? Have I switched some wires around during the motherboard installation that I haven't noticed? I took pictures before the replacement and everything seems to make sense. I also did replace the transformer at one point in time in all of this. The wires on the transformer just had the 24 volt side with yellow wires and the 120 volt side with black wires. Is there some sort of polarization of the wires that I need to worry about with this new transformer which could be causing all of these lower voltage occurrences? I have tried different combinations and it doesn't seem to be making a difference, but maybe I haven't explored this fully yet? Anyone have other ideas? Do I need to not buy my parts from these online suppliers which are supposedly new and look new? Should I just buy the more expensive parts from the local distributor (if I can get them to sell to me, a non licensed hvac person)? I have got quotes of prices but then get asked for my business name and hvac license number...
    Converted from NG to LP, Who did this work?

    Was a combustion analyzer used?

    When was the last time the Annual Maintence performed by a qualified tech, properly trained and equipped?

  4. #4
    Join Date
    Oct 2016
    Location
    Clearwater, Florida
    Posts
    1,573
    Post Likes
    I think this classifies as DIY type work which we aren't allowed to help with.

    I want to help you, but I don't think I can.

  5. #5
    Join Date
    Dec 2007
    Posts
    9,520
    Post Likes
    Quote Originally Posted by pecmsg View Post
    Converted from NG to LP, Who did this work?

    Was a combustion analyzer used?

    When was the last time the Annual Maintence performed by a qualified tech, properly trained and equipped?
    The Food Stamp Program, administered by the U.S. Department of Agriculture, is proud to be distributing the greatest amount of free meals and stamps EVER.
    Meanwhile, the National Park Service, administered by the U.S. Department of the Interior, asks us to "Please Do Not Feed the Animals". Their stated reason for this policy "... the animals become dependent on handouts and will not learn to take care of themselves."
    from an excerpt by Paul Jacob in Sun City, AZ

  6. #6
    Join Date
    Sep 2007
    Location
    edmonds wa
    Posts
    4,434
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    You need to quit screwing around with things you have no idea how to repair, before you hurt someone.
    UA Local 32 retired as of Jan 2020

  7. #7
    Join Date
    Jan 2020
    Posts
    2
    Post Likes
    Thread Starter
    The service tech says that I just need a new furnace, but this seems to be just a gas supply issue, and I am not ready to buy a whole new furnace for a problem that seems solveable. He reluctantly agreed to replace the 2nd motherboard as he thought the 13 volts might be too high as well, but basically doesn't know what to do next either. The new gas valve has the correct orfice installed and is set to the furnace specified 10 in of water column for LP. Is it normal for a relay to have 8 to 13 volts to the gas valve pre ignition (24 volts supplied to the coil). It seems odd that both gas valves seize up at times. More so now...Could the new inducer not be creating enough vacuum and consequently overheating the gas valve coil causing the seizing while not setting off the limit switches? The tech has not completed a combustion analysis yet other than a quick CO test at the vents to check the heat exchanger. I am at a loss... Any ideas?

  8. #8
    Join Date
    Jun 2014
    Location
    Dover, DE
    Posts
    11,862
    Post Likes
    I’d say if your having to do leg work for the tech, then you need a new tech.
    It’s a 24V system, not a 13V system. How can 13V be too high?
    I havent failed. Ive just found 10,000 ways that wont work. - Thomas Edison

    Its not whether you get knocked down, its whether you get up. - Vince Lombardi

    "In this house we obey the laws of thermodynamics" - Homer Simpson

    Local 486 Instructor & Service Technician

  9. #9
    Join Date
    Aug 2002
    Location
    Southold, NY
    Posts
    27,426
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    This has to be DIY!

  10. #10
    Join Date
    Sep 2007
    Location
    edmonds wa
    Posts
    4,434
    Post Likes
    Mods should shut this down.
    UA Local 32 retired as of Jan 2020

  11. #11
    Join Date
    Dec 2007
    Posts
    9,520
    Post Likes
    Quote Originally Posted by Homehvac9876 View Post
    The service tech says that I just need a new furnace, but this seems to be just a gas supply issue, and I am not ready to buy a whole new furnace for a problem that seems solveable. He reluctantly agreed to replace the 2nd motherboard as he thought the 13 volts might be too high as well, but basically doesn't know what to do next either. The new gas valve has the correct orfice installed and is set to the furnace specified 10 in of water column for LP. Is it normal for a relay to have 8 to 13 volts to the gas valve pre ignition (24 volts supplied to the coil). It seems odd that both gas valves seize up at times. More so now...Could the new inducer not be creating enough vacuum and consequently overheating the gas valve coil causing the seizing while not setting off the limit switches? The tech has not completed a combustion analysis yet other than a quick CO test at the vents to check the heat exchanger. I am at a loss... Any ideas?
    Not the correct way to check a heat exchanger.
    The Food Stamp Program, administered by the U.S. Department of Agriculture, is proud to be distributing the greatest amount of free meals and stamps EVER.
    Meanwhile, the National Park Service, administered by the U.S. Department of the Interior, asks us to "Please Do Not Feed the Animals". Their stated reason for this policy "... the animals become dependent on handouts and will not learn to take care of themselves."
    from an excerpt by Paul Jacob in Sun City, AZ

  12. #12
    Join Date
    Oct 2016
    Location
    Clearwater, Florida
    Posts
    1,573
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    Cooling the gas valve coil?

    Never heard of that before.

  13. #13
    Join Date
    Jun 2012
    Location
    Northern NV
    Posts
    2,088
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    Lookin' for love in all the wrong places.... (as the song goes.)
    A dying culture invariably exhibits personal rudeness. Bad manners. Lack of consideration for others in minor matters. A loss of politeness, of gentle manners, is more significant than is a riot.
    ― Robert A. Heinlein

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