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Cold Water coming out instead of Hot Water..When I need a hot shower...HELP

ww Member Posts: 282
I'm running a Beckett Af. Thermostat not calling for heat. boiler on for awhile..water comes out cold..wait more..comes out hot..then colder..what is wrong? 1 family house hot water radiator system.

Boiler has internal coil and goes on when hot water needed.


  • GCurloid
    GCurloid Member Posts: 2
    seek professional help

    Your post is lacking enough info to make any sort of diagnosis.   There are so many factors that come into play here, it is almost impossible to say where the problem lies.  Get a good oil heating man in there to check it out.
  • russiand
    russiand Member Posts: 73
    Most likely the mixing valve

    All of these types of tankless coil setups are plumbed with the tempering or mixing valve most likely like this. http://seek.autodesk.com/product/latest/agg/watts/1/Watts/717

    This type of valve usually fails within 5 years. There is a repair kit for it, but its frequently easier to replace with a better valve. Have a professional oil guy or plumber repair or replace the valve.  Also my advise is to look into upgrading to an indirect tank, as coil is the most expensive and least efficient way to get hot water these days.
  • billtwocase
    billtwocase Member Posts: 2,385
    age of boiler

    as stated, so much missing info. I would also add that if the water begins hot, and turns cold quickly, the coil could very well be no good
  • russiand
    russiand Member Posts: 73
    Very good point, much info is missing.

    Very true too much info is missing. One would have to figure out if the coil is plugged up with deposits, etc and is no longer effectively heating up water. However I have seen quite a few cases where the cheap Watts 70A's fail after just a few years. My own house had a coil when I first moved in, the mixing valve was so corroded in place you coulnd' turn the knob on top. Replacing the valve fixed the problem for the short term, still the hot water supply was not great at all. Ulitimately I went to an indirect tank anyways...
  • Patchogue Phil_2
    Patchogue Phil_2 Member Posts: 304
    Cold at just shower?

    Is it just at the shower that gets cold?  Or at all faucets too?

    If just at the shower then the problem could be the balancing shower controls.