Forum Discussion

72Blazerod's avatar
72Blazerod
Explorer
Sep 26, 2017

Pilot Light stays on to warm up the tank , then goes out?

Hi Guys,

I have a very vintage 1975 Prowler travel trailer with the original hot water tank. I can light up the pilot light no problem, it lights the burner which will warm up the tank and give me hot water. The problem is, the pilot light won't stay lit to light the burner to keep the water hot. I have to go out and relight the pilot light and wait for the water to warm up each time I need hot water? I think the thermocouple is okay, because the pilot light stays on and it heats the tank, it's just that it shuts off once it's heated and the water goes cold.

Any ideas? Do I have a blockage in the gas line or something? Let me know what you think.

8 Replies

  • jimlj's avatar
    jimlj
    Explorer
    Sep 29, 2017
    Cutting torch tip cleaners will have a cleaner the right size to clean the orifice. You can even use a single bristle of a stiff wire brush. Ditto cleaning the thermocouple. Ditto the possibility wind blowing the pilot flame out.

    My old Shasta trailer had the gas tube plugged solid by leaf cutter bee's when I used to live by an alfalfa field.
  • Old-Biscuit's avatar
    Old-Biscuit
    Explorer III
    Sep 28, 2017
    72Blazerod wrote:
    Thanks Old Biscuit,

    I think my LPG pressure is ok because my stove top and fridge work just fine right now. I think it might be a plugged/blocked orifice. Any tips on how to correctly clean the orifice?

    Thanks


    Soak in alcohol and then blow it dry with LOW pressure air
  • ScottG's avatar
    ScottG
    Nomad
    Sep 27, 2017
    Clean the thermocouple with a brass brush or some solvent.
    They get so covered in carbon that they get insulated. I have fixed many this way.
  • westend's avatar
    westend
    Explorer
    Sep 26, 2017
    My '71 had issues. I disassembled the burner tube and cleaned everything thoroughly and now it all works great. Most of the orifices can be removed with a socket and then soaked in strong soap or solvent solution. When done soaking, rinse and blow out with compressed air.
  • 72Blazerod's avatar
    72Blazerod
    Explorer
    Sep 26, 2017
    Thanks Old Biscuit,

    I think my LPG pressure is ok because my stove top and fridge work just fine right now. I think it might be a plugged/blocked orifice. Any tips on how to correctly clean the orifice?

    Thanks
  • DutchmenSport's avatar
    DutchmenSport
    Explorer
    Sep 26, 2017
    Those older style water heaters, that did not have the electronics the modern ones have, were very susceptible to wind blowing out the pilot. It might be something just that simple.
  • Old-Biscuit's avatar
    Old-Biscuit
    Explorer III
    Sep 26, 2017
    Pilot flame heats thermocouple which generates a milivolt signal that holds magnet open so gas flows to pilot.

    Pilot flame needs to engulf thermocouple at ALL times for milivolt signal to be generated

    When Main Flame lights off does pilot flame diminish is size?
    If propane system pressure is low..pilot flame dips/thermocouple not engulfed/milivolt signal drops out/magnet closes---no gas flow to pilot

    Clean pilot flame orifice and check system pressure---11"WC with at least 50% of propane appliances in service (demand placed on regulator....IF regulator can keep up with demand)

    So could be low pressure, bad LP Regulator or obstructed pilot tube/orifice


    1975 vintage trailer....42 years old
    Might be time to replace old parts on water heater

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