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happybooker1's avatar
happybooker1
Explorer
May 11, 2013

Help with non-lighting water heater

Hot water heater on '91 Gulf Stream Ultra. Mor-Flo brand. Electric ignition..

When I flip the switch inside you can hear the click as the switch sparks then the whoosh of gas and the burner lights. 5 seconds later it goes out. It will do this sequence 3 times and then it locks up.

Plenty of propane & burners on stove light just fine. I took it apart. The 'burner' is just a metal tube with a metal plate mounted in the middle of it.


This is the sparker right and the gas tube right?


This is an apparatus on the left side:






The bottom has a little pinhole in it where I assume the gas comes out to go into the burner tube. Somewhere I read where the thermocouple isn't sensing the heat from the burner lighting & is cutting off the gas. Can someone tell me where this would be located? Is it somewhere in the apparatus on the left? There are several electrical wires going into the top & bottom of it but I didn't mess with those yet.

5 Replies

  • Thanks for the help! I will try all that but probably not tomorrow. I'll let y'all know how it turns out.
  • Make sure all the electrical connections are clean and tight. From the appearance of the condition of your WH corroded connections could be very possible.
  • j-d's avatar
    j-d
    Explorer II
    It has some form of "Flame Sensor." In piloted water heaters, it's a Thermocouple. In DSI (Direct Spark Ignition) they call it Flame Sensor and I don't know if it works same as thermocouple does.
    What I think is happening is that the Sensor doesn't know the flame has lit, or it isn't telling the Logic Board that it has lit, or the Logic Board isn't commanding the Gas Valve to stay open because the Flame has Lit.
  • The 'apparatus' is the main gas valve....wires are power and ground to solenoids that open gas valve.
    Pinhole is the main gas 'orifice' that meters gas flow

    The 'tube' is main burner with spark electrode & ground wire.

    Blow compressed air thru burner tube.
    Clean spark electrode & ground rod with some emery cloth...check spark gap 1/8"
    Run a bottle brush thru combustion chamber/exhaust and blow out with compressed air.
    Remove gas orifice and clean it with alcohol, blow compressed air thru it

    Then reassemble.

    When power is applied to gas valve solenoids opening gas valve, spark electrode gets energized at same time.
    When main gas flame lites a millivolt signal is sent back to module (flame ionization) thru the spark electrode and high tension wire.
    It is used to prove main flame and keeps power on gas solenoids so valve stays open.

    Check for good clean tight ground connections and for good clean contacts on terminals.
  • You may have an obstruction in the "burner" tube. Clean it out the best you can and blow it out with compressed air.