Shower hot water temperature occasionally warm (not hot)

Discussion in 'Water Heater Forum, Tanks' started by lordmoosh, Jul 23, 2013.

  1. lordmoosh

    lordmoosh New Member

    Messages:
    115
    Location:
    USA
    Hello all,

    I have a 40 gallon Bradford gas water heater installed in 2004. I bought the house at the end of 2011. I do not know if the previous owner ever flushed the tank so I have not been flushing the tank. I would say 95% of the time I have no issues in the shower. I am always the first one up. Occasionally when I take a shower the water is just warm not hot. I always thought it might mean the shower handle parts need to be replaced (its a single handle for hot and cold) but today I tried running hot water at the bathroom sink and it was also not hot... just warm. I use a 1.5 GPM shower head. The water was just warm from the get go. My showers are about 15 minutes long. My thermostat on the water heater does not display in degrees so I cannot tell you exactly what temperature its set to. As I said before most of the time its fine just occasionally it surprises me with warm water. Thanks all.
  2. LLigetfa

    LLigetfa DIYer, not in the trades

    Messages:
    4,002
    Location:
    NW Ontario, Canada
    Does the sink have separate hot and cold levers to be sure you are drawing just from the hot side? Does the flow on the hot seem less than on the cold?

    Some possible reasons for temp variation:
    Heat traps sticking, reduce fow.
    Dip tube broken, resulting in blending.
    Pressure balance spool in single lever control sticky.
    Pressure balance diaphragm ruptured causing crossover.
    Temperature stacking caused by frequent small draws of water.
  3. lordmoosh

    lordmoosh New Member

    Messages:
    115
    Location:
    USA
    The sink does have separate hot and cold levers. The flow on the hot side seems about the same as the cold side. I am also using a 1.5GPM faucet for the sink.

    Is there anything I can do to test some of the things you have listed below as possible causes?

  4. LLigetfa

    LLigetfa DIYer, not in the trades

    Messages:
    4,002
    Location:
    NW Ontario, Canada
    If you have a crossover situation, the heat traps could still be sticking, but the crossover maintains the flow so you need to rule out a crossover first. Any fixture that has a single handle with anti-scald pressure balance could cause a crossover... the diaphragm types more so than the piston types. If you have shutoffs at the fixtures, turn them all off and see if that makes any difference.

    Usually if you have a deteriorated dip tube, you will find small bits of plastic coming out the draincock or trapped in aerators. With a bad dip tube, the water starts out hot but doesn't last.

    Temperature stacking causes the water to get hotter than normal at the top of the tank when repeated small uses of hot water causes the heater to fire. After the usage stops and the heater has time to sit, such as overnight, the temperature evens out top to bottom.
  5. Smooky

    Smooky Member

    Messages:
    623
    Location:
    NC
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