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water heater mystery

Phil_6 Member Posts: 210
Thanks everyone. I'll be snooping around over there next week and see if I can sort it out using all this fine advice.



  • Phil_6
    Phil_6 Member Posts: 210
    gas water heater trouble

    I've got a real head scratcher on my hands. I have a customer who had a 50 gal gas heater in his building. The pilot kept going out a few times a week. Gas valve, thermocouple etc replaced, still the same. The tank leaked and the heater was replaced under warrantee. New heater, same trouble. Hmmm. The installation is as typical as might be. Boiler and a water heater connected to a common flue pipe and into the chiminey. The basement is wide open, no room built around the equipment. No one goes down there or even opens the door except to light the #%#* pilot.The boiler is on the same gas line and the pilot never goes out. This happens even in the summer when the boiler is off.

    What the heck is going on here??


  • Guy_5
    Guy_5 Member Posts: 159

    It sounds to me like something in the area may be pulling the gas pressure down so low that the unit starves.

    The other possibility is an exhaust vent of some sort drawing air out at such a rate that it puts the pilot out.

    This sounds like one of those detective jobs.....
  • It could be a chimney not pulling.

    The pilot would snuff when the flue products built up in the combustion area.

    It could be a partly closed gas valve, even outside the building.

  • kevin coppinger_4
    kevin coppinger_4 Member Posts: 2,124
    what type..........

    and how large is the chimney? no blockages?
  • Dale
    Dale Member Posts: 1,317

    I would put a magnehelic or u tube pressure gauge on the water heater drip cap and fire it up, if it spikes down below 4 inches when the burner on the heater fires you have a pipe restriction to find. I had one of these and found a balll of pipe dope in the nipple in front of the heater. If you are on 2 pound gas let us know as there are other issues with that. You can also put a pressure recording gauge on it if the pressure is OK when you are there.
  • hot_rod
    hot_rod Member Posts: 21,872
    sounds like - tugging on my ear

    Sustained combustion chamber & flue tube condensation dripping onto the pilot burner - seen that happen more than once when all hot water is exhausted and the tank is filled with cold water with the burner running. On rare occasions, we've seen the condensation create a rivulet that runs across the basement floor and causes the HO to think the tank is leaking. Doesn't always put out the pilot, but one well placed drop will do the trick.

    I've also seen problematic pilot outtages following the much reduced pilot flames dating back to them being reduced to enhance energy ratings - used to be able to read by the light cast off from the old style pilot flames(G). Hey old timers, remember when they were adjustable? An oriface drill kit can rectify that, but be very careful to tread lightly or you'll end up with a torch!

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    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream
  • Oh, Dave

    How you kindle the memories.

    Big pilots and drill sets. Andersen & Forrester. Little bitty broaches that snap off. A turkey baster type huffer-puffer to blow out pilots full of dust. Measuring thermocouple voltage.

    Oh, what fun it is to .....

  • hot_rod
    hot_rod Member Posts: 21,872
    The yung-uns don't know this, but...

    Kohler made boilers at one time. So I'm standing there with the new building owner last week as we both stared at that hunk of Kohler cast iron that also has on it a conversion burner dating back to when Lincoln gave his 4 score & 7 speech - we're staring at it together, which seems to be what men do when confronted with living dinosaurs(G).

    So he says "We don't need to replace this, do we?".

    Good grief! The flue passages are large enough that you could pass a Munchkin through without touching the sides. Must be getting at least a 30% efficiency rating. Gotta love a bi-metal 3' long pilot safety, eh Noel? We don't need no steenkin thermocouples!

    His four page estimate was sent via fax today. At least his phone lines are in this century(G).

    To Learn More About This Contractor, Click Here to Visit Their Ad in "Find A Contractor"
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream
  • tim smith_2
    tim smith_2 Member Posts: 184
    ghost pilot outage

    Just a little story, an old ex gas utility dispatcher in Seattle worked for us, he told us of a head scratcher they had many years ago. The pilot would go out every day and they had many different techs go out and check and recheck this families furnace and test and test. No reason for it. But almost every day it would happen. Finally the owners went down to basement one evening and there was their little son with a straw, blowing out the pilot. HMMMMMMMMMM could it be deja vu. True story
  • Chaz
    Chaz Member Posts: 1
    pilot out again

    Possibly a faulty regulator on the gas meter. Check the pressure when the boiler starts up, if it drops too low or changes erratically it can pull the water heater pilot out
  • D lux_2
    D lux_2 Member Posts: 230
    I had one lihe Dave Yates said

    Ran it out of hot water and watched it drip right on the P light . Only went out On WASH day .

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