Welcome! Here are the website rules, as well as some tips for using this forum.
Need to contact us? Visit https://heatinghelp.com/contact-us/.
Click here to Find a Contractor in your area.

Valve and thermocouple good. Pilot will not stay lit

Tneily
Tneily Member Posts: 14
I am at a total loss. Its getting colder and I can't get my pilot to stay let for anything. Pilot assembly is clean with a strong blue flame. The control valve is good. New thermocouple that's throwing out 28. Positioning looks good and no kinks. I don't understand what is going on. Any information shared would be greatly appreciated. Thank you!

Comments

  • JUGHNE
    JUGHNE Member Posts: 9,750
    Picture of gas valve and of pilot burning, please.
    Tneily
  • Tneily
    Tneily Member Posts: 14
    I took the pilot out of the furnace for easier viewing.

  • Tneily
    Tneily Member Posts: 14
    I don't understand why the pilot wont stay lit. If the thermocouple is generating properly and the valve is good
  • ratio
    ratio Member Posts: 3,173
    Tneily said:

    the valve is good

    Is it? If the thermocouple is good and the valve still won't keep the pilot lit, well, that sounds like a bad valve to me.

    Tneilykcoppdelta T
  • Tneily
    Tneily Member Posts: 14
    I changed the valve to a new. Same problem. So I changed it back to the old one
  • ratio
    ratio Member Posts: 3,173
    Hmmm... Did you measure the closed circuit voltage? That takes an adapter.

    Oh, I found this to read. Maybe it'll help. There really aren't that many things to go wrong. It has to be one of them—even if you've already checked it, check again.

    Tneily
  • Tneily
    Tneily Member Posts: 14
    I only have a multimeter to test with. I am about to replace the thermocouple again and hope for the best. I have found a comment saying that the poster had encountered bad thermocouples that tested good. I will let everyone know how it goes.
  • ratio
    ratio Member Posts: 3,173
    I'd be a lot more suspicious of a second bad thermocouple than a second bad gas valve.

    And I put one of those thermocouple testers in my supplyhouse.com shopping cart for the next time I make a purchase. It looks like it'd be a handy service tool.

    Tneily
  • JUGHNE
    JUGHNE Member Posts: 9,750
    Is the end of the T-Couple well into the flame?
    Glowing red?
    Some T-couple adaptors will seem to hold it in place but will go a 1/4 to 3/8" more bury.
    Tneily
  • Tneily
    Tneily Member Posts: 14
    Thank you so much for the comments. I have the second consecutive thermocouple in as far as it can go. Still nothing. I don't know what to do. I've never had such a hard time trying to fix anything. Around the house or vehicle. No matter the level of difficulty. This has me feeling so beaten up
  • Tneily
    Tneily Member Posts: 14
    Also
    Yes, it's glowing red
  • Fred
    Fred Member Posts: 8,518
    That thermocoupler is way too far into the flame. Only the end 3/8's to 1/2" should glow cherry red. Having said that are you sure the other end of the thermocoupling is properly seated in the gas valve? Have you blown through the pilot tube to make sure it's not partially clogged with lint or dirt?
    Tneily
  • Tneily
    Tneily Member Posts: 14
    Yes, I have done all of that. I actually bent the bracket after a while. Just out of desperation in looking for any possible remedy. Not that I really thought that it wasn't hitting right. But this had me questioning all logical explanation
  • ratio
    ratio Member Posts: 3,173
    Tneily said:

    This has me feeling so beaten up

    Don't. You've got a real head scratcher going on, that's for sure. Are you cold, is this something that has to get resolved ASAP, or can you take a break & come back to it? If it's got to get done to keep the house warm you might need to call a service outfit, but there're a lot of smart people here, I'm sure we can get it working.

    Tneily
  • Tneily
    Tneily Member Posts: 14
    I can probably give it a bit before calling someone.
  • JUGHNE
    JUGHNE Member Posts: 9,750
    Is the end squarely inserted into the gas valve?
    Be sure there is no dirt in the gas valve receptor.
    Also, I always clean the end of the t-couple by rubbing it on pencil erasure and then again on clean blue jeans.
    Screw in with fingers, while moving tube up and down to be sure it seats all the way, you can feel when it bottoms out, then just a little tighten with tool. FWIW
    Tneily
  • Tneily
    Tneily Member Posts: 14
    Yeah, I've made sure several times that the end was clean and properly seated.
  • Fred
    Fred Member Posts: 8,518
    I can't see where the dial on the gas valve is setting. Is it on "OFF" or "Pilot" ? It looks like there are only two settings on that valve. If so are they "ON" and "OFF"? The dial looks like it may be broken. Is it set correctly?
    Tneily
  • Tneily
    Tneily Member Posts: 14
    No sir. It is set to off during the photo. But it has pilot and on, also.
  • Tneily
    Tneily Member Posts: 14
    The newer one that I had swapped in and out is the same thing. Just looks a little newer.
  • Fred
    Fred Member Posts: 8,518
    Is there a 24V power source to that valve? Is it properly connected? Does it require any power to hold the internal pilot valve open? Does your 24V transformer test out OK?
  • Tneily
    Tneily Member Posts: 14
    Yes there is a 24v power source properly connected. I have tested that source going into the control valve. But from what I understand. The pilot valve is not supposed to need anything more than what is provided by a good flame and thermocouple.
  • Fred
    Fred Member Posts: 8,518
    Do you still have the pilot/thermocoupler out? Does it need to be grounded? I'm at a loss
    Tneily
  • ratio
    ratio Member Posts: 3,173
    Did you try a(nother) new thermocouple with the new gas valve too? A double fault isn't very likely, but I think we're past the likely issues now!
    Tneily
  • HVACNUT
    HVACNUT Member Posts: 4,590
    Is it a boiler or furnace?
    I'm sure you're pressing and holding the red pilot button for at least a minute before letting go.
    Is the flame stable?
    For some reason, I can't upload your pics, so,
    Is there an induced draft motor?
    Is there excessive draft through the boiler or furnace? Whole house fan, or any large exhaust running?
    Tight boiler room? Meaning too tight.
    Tneily
  • Tim McElwain
    Tim McElwain Member Posts: 4,506
    Did you follow the test that ratio referenced. That is my step by step procedure for testing completely including doing a combustion test.
    Tneily
  • Tim McElwain
    Tim McElwain Member Posts: 4,506
    If you have trouble with following the procedure give me a call at 401-437-0557 and I will walk you though what you have to do.
    kcoppTneilyFormerly
  • Tneily
    Tneily Member Posts: 14
    Thank you to everyone for being so helpful. It turned out to be jus plain bad luck. I went and put the new valve back in. Then connected the newer of the new thermocouples. I must have tried a defective t couple that tested good. Before swapping the old valve back in. I knew that I didn't have the proper tools to do a true diagnosis. The thought of wasting $100 and still not get anywhere had me panicked. Thankfully I didn't try to return it to get my money back.
    It took ten minutes to switch back and resolve the issue. Including the time checking for leaks.
    Anyways. I wasted a lot of time by only havin a multimeter and trial/error to diagnose. But they say all is well that ends well. Thanks again to everyone who took the time to comment
    ratioMilanD
  • ratio
    ratio Member Posts: 3,173
    That's the way of it sometimes. Glad you got it figured out, & as Jamie said thanks for the follow-up.
  • jumper
    jumper Member Posts: 1,827
    A double whammy will get you every time.Usually there's a cascade effect. Mr. A misdiagnoses a problem so he makes the situation worse. Now Mr. B has to find two bad things.

    I was certain that Tnelly's issue was draft.
  • newagedawn
    newagedawn Member Posts: 586
    sounds like the ignition module is bad
    "The bitter taste of a poor install lasts far longer than the JOY of the lowest price"
  • JUGHNE
    JUGHNE Member Posts: 9,750
    I have never seen an ignition module for a standing pilot flame with old school Thermocouple.........have you?
    delta T
  • Tim McElwain
    Tim McElwain Member Posts: 4,506
    An ignition module is designed for a system with a spark ignition pilot system which proves by miroamps not millivolts.

    A thermocouple system has a pilot which is lit 24/7 and has no need for an ignition module. Two seperate systems.
  • j a_2
    j a_2 Member Posts: 1,796
    JUGHNE said:

    I have never seen an ignition module for a standing pilot flame with old school Thermocouple.........have you?

    That's a good one, me either
    JUGHNE
  • David37
    David37 Member Posts: 1
    Had the same problem with the pilot lighting and staying lit in my old RV. Cleaning the pilot orifice solved the lighting problem. Replaced thermocouple and still had a problem staying lit. Both new and old thermocouple gave 25-30 mv when tested. Lightly sanded the gas valve end of the thermocouple and gently scraped the female contact point in the gas valve with a phillips screw driver and the pilot lit and stays lit. The 30mv were not getting to the pilot light lock in coil.