pressure relief -- make it stop

Mike Anderson

I have a hot water heating system with baseboard radiation and an old steel compression expansion tank. I have recently had the pump replaced. Since then, every time the boiler heats, the pressure rises too high and the relief valve activates. After a short time I hear the water sloshing through the pipes. I don't understand why I keep getting air in the pipes. After I fast-fill the system then set the feed valve to the correct pressure, I turn the circulator back on and hear no water sloshing. But, during the first heating cycle the pressure increases so much that I either have to drain water or let the relief valve drain the excess water. On subsequent heating cycles I begin to hear the water slosh through the pipes again. A plumber said I need a new expansion tank and feed valve. I believe that I do need a new feed valve but I'm not so sure about the expansion tank. I don't want to spend unnecessary money, because I don't know if I believe that anything is wrong with the tank.
Any help would be greatly appreciated.
Thanks,
Mike

ed wallace

expansion tank

your expansion tank needs draining have your plumber drain it or talk you thru it better yet have it replaced with a pressurized expansion tank good luck

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ta finnegan

Relief valve.

First I would make sure you are pumping away from the boiler and check to see if you have an airtrol fitting on the tank. Waterlogging can cause some of the problems you described.

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jay_4

air in system

You never said where you were draining it from. If you drained the exp tank and the pessure comes back up it sounds as if your feeder is feeding past the set pressure.
Next time you drain the exp tank, purge the zones of air. Open the valve to the exp tank and get your proper pressure and then close the valve to the feeder for a day or two and see what happens.

Arthur

Pump sucking Air

Might pay to check that the new pump you installed is not sucking Air on the 'suck' side joint of the pump. It might not leak when off but could still'suck' Air, Or it could be that the new pump has a lot more suck than the old pump and now can suck air in though valve stems on the system including the rad valves which the old pump did not do.

gman

get a second opinion,another heating pro.my opinion would be ..replace the expantion tank. its also possible that tankless coil is leaking into system.why dont you trust your plumber?also feed valve.