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Help, My boiler is blowing over relief - A LOT.

Rich L.
Rich L. Member Posts: 414
If your water meter is spinning and you have nothing else on, are you sure the leak is fixed? You could have a leak under the slab.

There should be a pressure temperature guage on the boiler, what's it reading for pressure? If you're a single level slab home it should be reading around 12 psi without your pumps running. If it's reading higher than that your auto fill valve may be over filling.


  • Steve J_5
    Steve J_5 Member Posts: 3
    Help, My boiler is going over relief

    Looking for advice. I have a slab house & a leak (in a BB return line) appeared under the slab this weekend. I located & repaired the leak. I filled & purged with the fill valve opened to full pressure & the relief opened. I set the fill valve to 'normal' & the relief would dribble, then open, then dribble & open... So I replaced the relief valve. Same result, dribble, open. In addition my water meter is spinning with nothing else on. This was about 6:00 last night (sunday) rather than smash things I shut the supply & walked away. I'm not a plumber, just a homeowner with too many tools. I need advice. The boiler is gas & may have been firing while dry, could I have done any internal damage? or is my auto-fill valve overfilling? or something else?
  • Jordan_2
    Jordan_2 Member Posts: 14

    You could have a bad boiler feed or expansion tank. Try turning off the water going into the boiler, drop the boiler pressure to 12psi and run the boiler up to the high limit and see if the boiler exceeds 20 psi or so. If it does it is likely the expansion tank. But if the boiler pressure stays down then it may be the boiler feed sticking open.
  • Steve J_5
    Steve J_5 Member Posts: 3

    I'll try that tonight & let you know. Thanks
  • Steve J_5
    Steve J_5 Member Posts: 3

    I hope there are no more leaks. I fixed the first hole, then water came from further down the line. Chopped more of my living room up & fixed that hole, then while my father, my wife & I were watching for more leaks in the hole in my floor my 6 year old screamed about the water in the boiler room.
  • Bob Forand
    Bob Forand Member Posts: 305
    Expansion Tak

    Steve, another way to check your expansion tank is when the boiler is hot, the expansion tank should feel hot on the top if it is hanging upright, and cool on the bottom. Either way if the tank is good you should feel 2 distinct temp differences. Good luck....
  • herb_4
    herb_4 Member Posts: 17

This discussion has been closed.