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.

Gas Valve trouble! 911

Ray Landry
Ray Landry Member Posts: 203
Did you check draft? What about make up air? Sounds like one of the two is your issue..


  • Barrington White
    Barrington White Member Posts: 37
    Gas Valve trouble! 911

    I was working on a gas boiler. The unit wouldnt start. I lighted the pilot. The pilot stayed on. The gas valve would not come on. I checked all of my safeties. The safety by the gas valve at the bottom of the boiler was open. So I jumped it out. The gas valve opened and I had ignition. So I preceded to change the high limit. I changed the high limit. I turned on the unit then It began to operate, it shut off after the a few minutes.

    There is water pressure in the boiler. About 15 to 20 PSIg. The draft damper is open and the chimney is clean. The circulators are pumping and the thermostats are working. The water temperature is at 60 degrees. So I jumped the limit out again. This time I let it run. I noticed that the bottom of the boiler was getting extremely hot and the wires were getting soft. So shut it down immediately. I concluded that the gas valve wasnt regulating the gas pressure properly.

    Could up please lend your expertise.
  • jp_2
    jp_2 Member Posts: 1,935
    wait a minute

    if the boilers melting wires and the water temps is 60F, you better call a pro before you destroy your boiler!

  • Did you take off the jacket and look inside the boiler to see if it is plugged up with dust or soot? are you 100% sure the vent damper is opening?
  • Mitch_6
    Mitch_6 Member Posts: 549
    I f you do not know how you

    should not touch this one since the hazard level is high.

    Could be poor draft at breach (curtain effect)

    plugged boiler, over fired boiler etc.

    all possible high co issues and venting back into the house plus the fact that you can fry your wiring.

    Have someone with the proper draft, combustion and gas pressure testing equipment check it out.

    Mitch S.

    To Learn More About This Professional, Click Here to Visit Their Ad in "Find A Professional"
  • Dave_4
    Dave_4 Member Posts: 1,405

    If this a modern boiler with a TFE (roll-out switch) at the bottom near the burner, and it tripped, you need to CALL A PRO NOW!!

    It sounds like the boiler is sooted up and it would be VERY dangerous, if not DEADLY!! If you attempt to fire before corrective action is taken, you may be putting the occupants of this building (as well as yourself) at mortal risk.

    Three ways this can happen.

    Blocked flue

    Incorrect gas pressure

    lack of combustion air

    Please, do the right thing and disconnect the gas and electric before someone gets killed.

    Robert O'Connor/NJ

  • Empire_2
    Empire_2 Member Posts: 2,343
    If unfamiliar with trouble shooting...

    I would strongly recommend on calling a PRO.. What you changed is not a hi limit safety!!!! This needs immediate attention or someone can get hurt or killed. No disrespect intended, but if you are a HO or service tech,...call in some help. The problem can be addressed and corrected with some knowledge...;-) Why would you go to the chimney if the Roll out safety limit was tripped? A quick glance at the openings to the Heat exchanger would probably give you a tell tail sign of what is going on. GV over firing??? Once in my 23 year career did I see this and it was on an industrial job that had outside influences that made the valve malfunction.

    How can you conclude that the GV is not regulating without a manometer?

    Mike T.
  • Steamhead (in transit)
    Steamhead (in transit) Member Posts: 6,688
    Bigb, if you're not a pro


    If you are a pro but aren't familiar with this situation (don't sweat it, we all had to learn sometime) you need to hand this job off to someone who is. Then get to Tim McElwain's gas training center in Warren, RI as soon as you can.

    I suspect the boiler has plugged with soot, which could be caused by overfiring, blocked chimney or some other cause.

    To Learn More About This Professional, Click Here to Visit Their Ad in "Find A Professional"
  • Not a high limit

    It sounds like you are having problems with your Roll Out Switch. If you are, you have a serious and dangerous problem.

    Get someone with the proper expertise and equipment to inspect and test that heating unit.

    Shut it off until you do.

    Good Luck

    Ed Carey
This discussion has been closed.