Forum Discussion

Koda10xx's avatar
Koda10xx
Explorer
Apr 29, 2019

Hot water tank only works half the time

Hi guys new here and looking for some help. My hot water tank only wants to fire on LP maybe half the time. One day I can flick the switch and it fires instantly and works fine then nothing won’t start no matter how many times you try. Come back in 4 hrs and bam! Fires up or sometimes won’t start for days! . Gas pressure is good , spark is good , no clogs , battery’s good. I thought it was the reset thermal fuse so I bypassed it with no luck . Then I bought a new gas valve and same issue . I’m thinking it could be the control board any other ideas??

12 Replies

  • Koda10xx's avatar
    Koda10xx
    Explorer
    Apr 29, 2019
    If it were a gap/spark issue wouldn’t I still be able to light it by hand while it’s trying to ignite??
  • Old-Biscuit's avatar
    Old-Biscuit
    Explorer III
    Apr 29, 2019
    You state spark electrode is firing.....gas valve has voltage and it works sometimes
    Then it is either GAP issue, dirty orifice or burner tube.

    Bad circuit bd..you would NOT have spark or voltage on gas valve
  • Koda10xx's avatar
    Koda10xx
    Explorer
    Apr 29, 2019
    When it goes click, click , click ZERO gas is coming out of the valve , so I don’t believe it’s a gap issue.
  • Old-Biscuit's avatar
    Old-Biscuit
    Explorer III
    Apr 29, 2019
    When gas valve is getting voltage is spark electrode firing...CLICK, CLICK, CLICK????

    Gas valve only gets voltage for 6-8 seconds while electrode is sparking.

    IF it is sparking then need to adjust 'gap'
    Too far/too narrow and no flame
    1/8"---3/16" MAX

    If no sparking..then bad connection on transformer (2000V +) or bad circuit board
  • Koda10xx's avatar
    Koda10xx
    Explorer
    Apr 29, 2019
    I did check with the multimeter on the valve solenoids when it won’t fire and it is getting voltage. That’s what led me to buy a new gas valve . With the new one installed I have the same symptoms. Possibly new one is junk too?
  • STBRetired's avatar
    STBRetired
    Explorer
    Apr 29, 2019
    Do you have a multimeter? You need to check for voltage at the gas valve when it fails to send gas to the burner. If there is voltage at the gas valve but no gas flow, that would indicate a failed valve. If there is no voltage at the gas valve while the igniter is sparking, that would indicate a control board failure.
  • Koda10xx's avatar
    Koda10xx
    Explorer
    Apr 29, 2019
    Yes I did , when it fires it fires instantly and the flame is perfect .

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