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  1. #1

    Hmm adjusting honeywell gas valve

    Hi, I just replaced the primary heat exchanger in my (1995) Goodman gmpn 100-4 furnace.I did so because it was cracked (in several places internally as well as the one external)causing flame roll out and constantly tripping the sensors.I didnt touch any adjustments in the gas valve but once complete, when I fired it up, I got a serious roll out upon ignition followed by crossover flames(the ones between ea. burner) that were too high,once again tripping the sensors.
    I turned the shut off valve to about 3/4 closed which throttled the flame down and everthing is working/looking great...Problem is I KNOW thats not how the system is supposed to be adjusted.Im guessing one of the screws on the honeywell gas valve will adjust/throttle the gas flow but not knowing exactly how am a little hesitant to mess with it.
    I believe the honeywell model # starts with 820,though my eyes aint what they used to be...just to the right of the on/off valve there is a large screw and near that a smaller one...are there instructions online somewhere that gives detailed info. on adjusting these?Also Im a bit puzzled,if I didnt mess with the adjustments (just replaced the heat xch. and put everything back as it was)why is it now burning so much stronger? Im just a homeowner but used to be a pipefitter and have some limited knowledge...thanks

  2. #2
    Join Date
    Nov 2004
    Location
    South Carolina
    Posts
    1,840
    call a service company to look at it, please. you are in over your head, i mean that nicely

  3. #3
    Join Date
    Dec 2002
    Location
    Rochester, MN
    Posts
    5,304
    I agree, get someone out there to look at it.. it may not be the gas valve.

    You got the right heat exchanger??

  4. #4
    Join Date
    Sep 2007
    Location
    Maryville Tennessee
    Posts
    92
    You have to have a manometer to adjust gas pressure and that is most likely not your problem. Not to be rude but you need to call a service company fast and not touch anything else. This is the problem with distributors and contractors selling parts to homeowners.

  5. #5
    Join Date
    Jul 2007
    Location
    Tulsa, OK
    Posts
    986
    If in fact you still are alive tomorrow after not listening to us and tried adjusting things yourself I urgently suggest you shut it down and call and bite the bullet and pay a pro for more than just service experience. He may find where your gasket is leaking and causing roll out or worse, so be honest and confess "you" did the xchanger replacement.

  6. #6
    Join Date
    Sep 2007
    Location
    southern IN
    Posts
    527
    I must agree with the other four! Death or a house fire isn't worth saving a few hudred.

  7. #7

    thanks,let me explain

    Thanks for the concern/warnings...but I'ld really like info. Im a retired fitter whose worked on everthing from powerhouse construction/shutdowns to pharmaceutical plants,to re-tubeing huge commercial boilers...I know how to bolt a heat x in...
    1.Yes,its the correct H.x.
    2.First thing I checked...no gas leak
    3.Its not really roll out upon ignition, a poor description earlier...Its sort of a "poof"(surely theres a term),when she first lights,and you can see some flame escape/backfire (too much gas press.)
    4.Once lit theres no roll out but the (crossover flames?) flames between burners are too tall (too much gas).heating her up a little
    5.once throttled down she cycles and lights perfectly
    I apologize for not knowing the correct terms,therefore the laymans description...but I think I did a fairly decent job for my first furnace h.x. You guys are getting me a bit paranoid however so I guess I'll get someone to look at it...Im 98% certain the gas press. just needs adjusting though,if I knew how(and I think I might)Ild do it but instead I'll call someone.
    But seriously,I know your hearts are in the right place...THANKS

  8. #8
    Join Date
    Dec 2006
    Location
    Middle Tennessee
    Posts
    11,347

    *

    Quote Originally Posted by 87electraglide View Post
    Thanks for the concern/warnings...but I'ld really like info. Im a retired fitter whose worked on everthing from powerhouse construction/shutdowns to pharmaceutical plants,to re-tubeing huge commercial boilers...I know how to bolt a heat x in...
    1.Yes,its the correct H.x.
    2.First thing I checked...no gas leak
    3.Its not really roll out upon ignition, a poor description earlier...Its sort of a "poof"(surely theres a term),when she first lights,and you can see some flame escape/backfire (too much gas press.)
    4.Once lit theres no roll out but the (crossover flames?) flames between burners are too tall (too much gas).heating her up a little
    5.once throttled down she cycles and lights perfectly
    I apologize for not knowing the correct terms,therefore the laymans description...but I think I did a fairly decent job for my first furnace h.x. You guys are getting me a bit paranoid however so I guess I'll get someone to look at it...Im 98% certain the gas press. just needs adjusting though,if I knew how(and I think I might)Ild do it but instead I'll call someone.
    But seriously,I know your hearts are in the right place...THANKS

    thats a good decision on your part!



    .

  9. #9
    Join Date
    Jun 2001
    Location
    Louisville, KY
    Posts
    12,189
    Thanks for taking their advice.
    Perhaps you should have read the instructions before calling.

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