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Air bound domestic hot water?

I have a 3 section boiler with a domestic hot water coil. I was doing some rough in plumbing on the second floor and had to shut down the water to the house for several hours. I did not shut the boiler off, as I was the only one home and frankly forgot. When I was finished I turned the water back on for the house. A couple hours later I went to take a shower and the hot water started out hot but then turned cold in about 40 seconds, this dies this at every faucet in the house. . I went to the boiler and it was firing and at temp. I checked the hot water feed off the boiler and it was hot for about 8 feet until it T-ed off. If this is air bound
, how do I bleed it. I capped the new plumbing on the second floor, could this be the problem?


  • lchmb
    lchmb Member Posts: 2,997
    or you got some sediment in your mixing valve.. I doubt it's an air issue, as the water would just push it out. Other possibility is you crossed some pipes so your mixing hot with cold.
  • the_donut
    the_donut Member Posts: 374
    60 psi should be able to crush any air in the line and force it out of the line through the faucet. Pictures of your plumbing would be helpful. Do you have 3 valve bypass setup or a thermostatic mixing valve?
  • DZoro
    DZoro Member Posts: 1,048
    Where does it tee off too?
    Do you have a domestic recirculation pump?
    Mixing valve?