Results 1 to 10 of 10
  1. #1
    okay I'm commerciall don't remember the sequence for a res. furnace, but...I got a 20 yr. old 90% that's in good shape, no gas valve voltage; trial for pilot- good nice pilot flame; this has a pilot module which has 3-wires which .apparantly switch the voltage from the pilot solenoid of the gas valve over to the main valve...I don't think it is necessary to check millianps,or such, it appears it is bi-metal and physically swithes over once pilot is lit. The dang thing is not swithing over so do I replace the pilot "module" and does this come in one piece. As you know it is not a easy process to remove,inspect,re-attach said components.Any help,background would help..
    payne plus 90 circa 1985

  2. #2
    Join Date
    Jan 2004
    Location
    PA
    Posts
    68,793
    W're not allowed to answer tech questions in teh resi forum.


    Reg as a pro, and ask questions of this nature there.
    Contractor locator map

    How-to-apply-for-Professional

    How many times must one fix something before it is fixed?

  3. #3
    Join Date
    Jul 2006
    Location
    NW burbs of Detroit
    Posts
    6,058
    Gonna go out on a limb here. Did you post you were "commercial"? It's kinda vauge. Clearify and we'll see what happens after.

  4. #4
    Yea ,I meant I commonly work comm.HVAC and I don't see this style much...memory ain't what it used to be aand I'm helping out friend. I should be able to answer any helpful replies/questions which assists me in resolving the lack of main burner flame. Thanks

  5. #5
    Join Date
    Mar 2004
    Location
    SE Michigan
    Posts
    18,223
    If the 3 wire pilot isnt closing the circuit for the MV, then you have to replace the 3 W pilot. You will have to use the old electrode unless you get a new one and position it the same as the old.
    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

  6. #6
    Thank you This is a sprk ignitor set up and the 3-wire pilot is being used as pilot sensing isn't it? Because it is hard to access I did not pull it out and inspect it but the spdt contacts never change..do you think the flame impingement is an issue or does the 3-wire component commonly fail on these things?

  7. #7
    Join Date
    Jul 2002
    Location
    St Paul, Minnesota
    Posts
    3,468
    Do I replace the pilot "module" ?
    yes. however cleaning the long metal strip inside with some steel wool can be a temp fix. Also, just like all pilots, they get crap buildup at the oriface and this lessens the pilot flame heat which causes same symptoms. But if that one hasn't been changed in a long time, I would replace it for a buddy.

    Does this come in one piece?
    yes. Including new oriface and nut.

    As you know it is not a easy process to remove,inspect,re-attach said components.

    If it were easy, we would be out of work. Stubby nut driver 1/4" to remove bottom tray of burner helps. Even made my own more stubby nut driver. Welcome to residential.

    Any help,background would help..

    You do know that you are guessing and changing parts on hunches, right. That's ok, it is done all the time in residential. Preferable way is to track voltages with a meter and so forth......but, a new pilot module is not going to hurt. Ever find bad heat exchangers in commercial carrier units? Of course you do. So do we in 20 yr old units...all the time. Combustion analysis helps find them.
    payne plus 90 circa 1985

    [Edited by MikeJ on 10-29-2006 at 09:53 PM]

  8. #8
    Join Date
    Jan 2002
    Location
    Ft.Worth,Tx
    Posts
    4,584
    Originally posted by steamfitter55
    okay I'm commerciall don't remember the sequence for a res. furnace, but...I got a 20 yr. old 90% that's in good shape, no gas valve voltage; trial for pilot- good nice pilot flame; this has a pilot module which has 3-wires which .apparantly switch the voltage from the pilot solenoid of the gas valve over to the main valve...I don't think it is necessary to check millianps,or such, it appears it is bi-metal and physically swithes over once pilot is lit. The dang thing is not swithing over so do I replace the pilot "module" and does this come in one piece. As you know it is not a easy process to remove,inspect,re-attach said components.Any help,background would help..
    payne plus 90 circa 1985
    be sure and check out that furnace after you get it up again, I was out on Day-Night and needed to replace spark electrode , wasn't easy to find either, several parts houses and finally got one, went back installed it and completed maintenance and guess what second cell cracked blowing flame out of hx and checked draft ok, co was 200+.

    Carrier Infinity system going in tomorrow also second unit which was ok is being replaced also.
    Gas 80% horizontals
    Infinity 4.0 ton
    Infinity 2.5 ton
    "Everyday above ground, is a good day".
    "But everyday that you have made a difference in someones life, may insure you stay above ground a little longer".<aircooled>

  9. #9
    just for the sake of clarity...the spark ignitor lights off the pilot flame normally. I'm used to a grounding rod or even a thermocouple proving a pilot flame , but this has a spdt switch which must be mechanical,right? It is warmed by the flame..swithes over and allows a cicuit to the main valve. I think this is what's happening because of the lack of any electronics. Do you mind telling me what the long metal strip does for my own sake..I bet if I had taken this component out it would be obvious.Also, I removed the orifice and inspected, it was fine. I didn 't rod it out but in hindsight it wouldn't of hurt. So I am going to replace the pilot flame sensing switch. Full report to follow

  10. #10
    Thanks for the tip on removing the bottom tray..New pilot module worked and the pilot lit off, warmed bi-metal and valve oopened normally..One thing ,the pilot flame appears larger than needed. I used the new pilot orifice which came with ass'y. Is there multiple orifes for this? No, I did't use the propane orifice; the new module stated for natural gas only. Johnstone supplied part.
    It appears there is pilot adj. on the gas valve if I need to adjust. Also, the pilot flame stays lit during operation. I hope this is common.
    Come on back

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •  
Comfortech Show Promo Image

Related Forums

Plumbing Talks | Contractor Magazine
Forums | Electrical Construction & Maintenance (EC&M) Magazine
Comfortech365 Virtual Event