Oil Hot Water Heater Shuts off every two days! Help!

Discussion in 'Plumbing Forum, Professional & DIY Advice, Tips & ' started by truthfreesyou, Dec 10, 2008.

  1. truthfreesyou

    truthfreesyou New Member

    Messages:
    9
    Hi, I am new to the forum, and I am very frustrated with my problem:

    Every two days, my oil fired hot water heater shuts down. I have to hit reset manually, and then it works perfectly for two days. Then it shuts down again.

    (I don't know if this is related, but I also have the problem of hot water coming out of the cold faucet for the first 15 seconds from every sink in the house, but I am not worried about this right now, unless these two problems may be related.)

    BUT MY MAIN CONCERN IS THAT I GOTTA GET THIS BOCK OIL HEATER TO RUN CONSTANTLY, AND NOT TURN OFF EVERY TWO DAYS!! ANY IDEAS????
  2. Gary Swart

    Gary Swart In the Trades

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    If it was gas, I'd suspect the thermocoupler, but I don't know if an oil fired heater uses one.
  3. Cass

    Cass Plumber

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    Location:
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    It sounds like you might have a bad thermostat and the high temp cut off is working and shutting it down...if it is over heating and you don't have a expansion tank your thermal expansion may be the reason why you are getting hot water on the cold side of the faucets for 15 seconds...
  4. nhmaster

    nhmaster Master Plumber

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    If you're hitting the re-set button to get it started then there's a problem with the oil burner and you need to call a service tech. It could be any one of about 20 different things.
  5. Redwood

    Redwood Master Plumber

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    I would concur with NH Master that you need an oil burner service tech.

    The hot water for the 1st 15 seconds is hard to say why. Do you have a hot water recirculation system?
  6. truthfreesyou

    truthfreesyou New Member

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    i have had multiple service calls to deal with this. they have all tried different things - cleaning the lines, pumping oxygen through the fuel lines, etc. but it hasn't worked.

    the interesting thing about the problem is that it usually happens when the heating furnace goes on. (i.e. it doesn't happen over the summer, only during the winter months when i am also using oil heat)

    i suspect that somehow the two machines are competing for the same supply of oil, and the furnace "wins" the fight, therefore causing the water heater to shut down as if it didn't have fuel.

    does this make sense? i am not a tech, but i suspect this...

    anyone??
  7. wallyworld

    wallyworld New Member

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    21
    There is a single oil line that tees off to each unit? That doesn't seem right, if one was on and the other off it could suck air from the off unit. Must be some check valves in there?
  8. Cass

    Cass Plumber

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    Chech the gal. / hr. rating on the furnace nozzle and the rating on the WH...add them together and then see if you can figure the amount that will gravity feed through the line...Do you know what size the feed line is coming from the oil tank?
  9. nhmaster

    nhmaster Master Plumber

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    If you have two appliances teed off the same oil line there is a very real possibility that the oil line is not large enough for both units, especially if it's only 3/8". One unit will pull through the other and if both are running they can pull enough suction to cause cavitation in the oil line.
  10. truthfreesyou

    truthfreesyou New Member

    Messages:
    9
    i think this is the problem. the service tech is coming today to install a preference switch, (or something like that,) which automatically gives preference to the water heater when both are pulling at the same time.. he said this will prevent the shut-downs. have you heard of this?
  11. truthfreesyou

    truthfreesyou New Member

    Messages:
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    help!!!!! the service tech came and installed a preference switch which temporarily shuts off the furnace when the hot water heater activates, so the furnace wouldn't suck the fuel from the heater....

    IT DIDN'T WORK!!!!! THE THING HAD TO BE RESET THE NEXT DAY, AND THE DAY AFTER, ETC....

    could the problem be electrical?? i am at my wit's end, because nobody can figure this problem out.. the machine is running perfectly, has been cleaned, serviced, etc.. just this damn shutoff problem.

    could the problem be that the machine is tripping the electrical fuse and therefore shuts down? i don't think so, because i never have to change the fuse or flip the switch, just hit reset... but i just don't know what to do!!!

    help!!!!!
  12. Cass

    Cass Plumber

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    Location:
    Ohio
    What kind of reset is it thermally activated or strictly electrical...has the reset button been replaced?
  13. truthfreesyou

    truthfreesyou New Member

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    i am not sure, but the reset button works. the unit goes back on, then shuts off later.
  14. Cass

    Cass Plumber

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    Location:
    Ohio
    If it is thermally activated and it is going bad that may be the problem...is the water ever super or excessively hot before the reset shuts off?
  15. Verdeboy

    Verdeboy In the Trades

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    I agree 100% with this answer.
  16. truthfreesyou

    truthfreesyou New Member

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    so are you saying that after the machine fills up with hot water, the thermostat is kicking it off? interesting.

    also, i do agree that these two problems are related, and therefore this could be kicking off the machine..

    i am going to print this out and when the tech guy comes tomorrow (again), i will make sure he reads this...

    more updates tomorrow!

    thanks so much,
    mitch
  17. truthfreesyou

    truthfreesyou New Member

    Messages:
    9
    one thing i know is that when the cold water faucet turns on, the first water that comes out is usually scalding hot... then it gets cold... this could support your idea that the problem is the thermostat, and that is why the unit is shutting itself down.

    but would this make it go to reset or just temporarily shut down??

    - mitch
  18. nhmaster

    nhmaster Master Plumber

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    3,189
    Location:
    S. Maine
    Neither the thermostat nor the high limit have anything to do at all with the primary control safety circut. They are totally separate circuits. Not sure what a prefrence switch is, never heard of one. If the oil lines are 3/8," switch or no switch, there is too much restriction there and the oil line is cavitating. In fact, installing check valves may have worsened the suituation due to the added restriction of the ball check.
  19. Verdeboy

    Verdeboy In the Trades

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    2,051
    I think he is saying that the thermostat is no longer working properly, and the water is getting so hot that a safety high limit switch is turning it off.
  20. Redwood

    Redwood Master Plumber

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    7,453
    Location:
    Connecticut
    The high temp will not cause the burner to go out on reset!
    As NH Master stated they are separate controls.
    The high limit and aqua stat interrupt the 120 VAC supplied to the burner assy.
    The oil burner primary relay recieves this voltage and distributes it as needed for the burner to operate unless the burner fails to fire at which time it goes out on reset.

    Take a read here...

    Bock Water Heaters Engineering Manual
    Last edited: Dec 18, 2008
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