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    what cause sa hot water boiler to flash to steam...limit @ 190

    oil-2-4-6-gas
    oil-2-4-6-gas Member Posts: 641
    in THE MAIN WALL
    i just came from the same exact call ---basement renovated turned into an apartment --the zone was airbound --cold water in the pipes then the pump would move a little water ---hit cold water say at 65* with a little 190* makes a lot of noise -purged the system --end of problem --

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    Comments

    • bluemoon
      bluemoon Member Posts: 41


      I have a hot water boiler...limit set @ 190 & satisfied...a new zone comes on line & the return hammers like crazy...steam?
    • Big Ed
      Big Ed Member Posts: 1,117
      New Zone?

      Only on the new zone? How is it hooked up to the system? Does it still make the noise if you lower aquastat to say 160*?
    • john coulson
      john coulson Member Posts: 3
      flashing

      Are you pumping away from the expansion tank? what model zone valve? is it on the supply or return?
    • steve z.
      steve z. Member Posts: 11
      Hot water / Steam

      The piping may be wrong, but a quick "patch" is to raise the fill pressure to 20 -25 psi...This will make your boiling point aroung 240 -250 degrees thus eliminating
      the flashing...Extrol precharge must be raised as well.
      There is a flow problem though....
    • terry_5
      terry_5 Member Posts: 92


      I had this problem,last year!My zone valve were place on the supply side creating the prob,Once placed on return no more prob!
    • Eric_20
      Eric_20 Member Posts: 3
      If you are using a zone valve be sure that

      you have the flow direction correct, most zone valves will water hammer when they cycle,if they are backwards.
    • bluemoon
      bluemoon Member Posts: 41


      >>>We've located a 2nd circulator in a remote closet in the basement w/2 zone valves serving 2 radiant floors...this zone maybe pulling from the boiler return...then when another zone comes on & feeds cold water into the return...a little thunder storm develops?...system was last renovated 12 years ago...been fine all along...???
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