Suburban SW6P water heater too hot on low setting - fires up constantly

Discussion in 'Heating / Cooling Systems' started by dreeveal, Aug 8, 2017.

  1. dreeveal

    dreeveal New Member

    Jul 20, 2017
    2008 Fleetwood Evolution E3
    Suburban SW6P Water Heater

    I recently acquired this trailer that has been kept in excellent condition and maintained very well. It was disclosed the water heater wasn't working. The pilot light simply wasn't getting any propane to it so it would not light. I acquired and installed two new parts which fixed that problem (a new OEM burner w/ orifice #010813 and a new pilot burner assembly#161156). The pilot light is nice and blue and slightly less than the size of an almond.

    My problem now seems to be temperature and the frequency and length of time which the unit fires up and heats the water. The water comes out of the tap dangerously hot, almost boiling. Also, even though the water is almost boiling hot, the furnace kicks on quite often, maybe every 20-30 minutes in 80 degree weather in order to maintain that high temp. The pressure release valve on the unit seems to be in good condition and releases water if you test it manually by manipulating the lever. However, the water doesn't seem to be hot enough (210F I believe is the limit) to trigger that safety feature. I have not heated the water heater to the hottest setting to attempt to test this.

    If you are familiar with this model, there is a temperature control directly on the gas valve with about 10 settings going from Low to Med to High. I have it set to the lowest temperature. I have also confirmed that this temperature control is at least somewhat functional, because after the furnace has stopped firing on the Low setting, if I turn it up a click or two the furnace will immediately fire. If I turn it back down the furnace will immediately stop firing.

    So, all in all, it seems to be functioning perfectly except for the fact that the Low setting is extremely hot and it fires up extremely often to keep it at that elevated temperature. Anyone out there an expert with these and has seen this before? Thank you -
  2. Antipodes

    Antipodes Call me Paul

    Jan 28, 2015
    Christchurch, New Zealand
    I got rid of our water heater of the same type and fitted a direct ignition type.
    I had the opposite problem on mine and if I remember correctly, the knob can come off and be repositioned to the hot end then turn down again and re-secure. Edit: remove in the colder position.
    But memory is a bit fuzzy on that?
    Last edited: Aug 8, 2017
  3. theseus

    theseus Centerville, OH

    Feb 6, 2007
    Centerville, OH
    Here is the water heater service manual.

    If I had to guess I would say that the gas calibration is off, but I not a technician.

    Incidentally I had a sort of similar problem with my Norcold refrigerator. After I replaced the orifice, the gas was flowing through so strongly it was freezing stuff on the lowest settings. After running for a few days, it settled down to normal operations, requiring me to turn the flame up.

    Like Antipodes, I have replaced my sw6p with a sw6d model. I chose the sw6de. No standing pilot light and only on when I want it to be. If you can't solve your problem and decide to replace it, I would pay the extra 20 to move up to a sw6d. D is for direct spark, P is for pilot, and DE is direct spark and electric.

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