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Hot Water Furnace - pressure

You are bothe right in the possible causes.


  • Lee Wallin
    Lee Wallin Member Posts: 1
    Hot Water Furnace - pressure

    The pressure release valve on my furnace was leaking. I flushed the system and replaced the valve. It is still leaking. I watched the pressure rise as the temp came up. It went over 30 lbs when the temp was 140-150 and began leaking. What can cause the pressure to rise other than the temp?

    Thanks for your help.
  • Lee, wrong forum but it sounds like............

    you have a expanison or compression tank problem. Tank is water logged so now when water gets hot, it doesn't have a place to expand too. Post a picture on the wall and I'm sure someone will be able to tell what to look for.
    P.S. You don't have a furnace, you have a boiler. Hope this helps. John
  • will smith_4
    will smith_4 Member Posts: 259

    Could also be that the auto fill has failed, and letting city pressure into the boiler.
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