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Water gets cold when running the tub

I just moved into my house a couple months ago it was summer time now as the temperature gets colder it doesn't seem to be holding the hot water as long I have hydrostat 3200


  • mattmia2
    mattmia2 Member Posts: 4,319
    Some pictures would help. What is the boiler? What does it use to make hot water, is it an indirect tank or a tankless coil or what? As the outdoor temp gets colder, most municipal water supplies get colder so the amount of hot water a system can make decreases. Ideally the system would be designed so that this is still enough for your needs.
  • STEVEusaPA
    STEVEusaPA Member Posts: 5,446
    edited November 2021
    All of that ^^^ and do you have a mixing valve at the boiler/water heater?
    Keep in mind if it's not storing hot water with an indirect, it will never keep up for a tub.
    These calls usually come in when it gets very cold for a sustained time as now the incoming water temp could be in the high 30's low 40's and the tankless coil can't produce/maintain enough hot water.
  • Jamie Hall
    Jamie Hall Member Posts: 17,745
    And furthermore... if there is a hot water tank, how big is it? What is it fired or heated by? For reference, you need at least 3 gpm from a tankless or 30 gallons from a tank -- at 140, with a mixing valve -- for a standard size tub.
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
    EBEBRATT-Ed Member Posts: 11,109
    And your HW should be120 at the fixtures you should get a thermometer and measure it.