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Steam boiler gaining water

Loki Member Posts: 1
Hello, we have a 2-pipe, older steam system in our home, which also provides our hot water. (its old, but we have no idea how old) We experienced a problem with the water level in the boiler getting *much* too high earlier this winter (without one of us adding water), and had someone out to look at it. We do not have an automatic feed system, so we were told the likely culprits were a slow leak in the faucet/valve that is used to add more water manually or a leak in the domestic hot water lines inside the boiler. We had someone replace the manual feed valve with a new ball valve (it had been regular faucet-type) and kept an eye on things. To our relief, the problem disappeared - the system maintained water level and all was well. This seemed to fix the problem - the boiler maintained water level for 2 weeks, and now the same problem has cropped up again, seemingly overnight! The manual feed valve is brand new, so I would be surprised if that were leaking again, and if it were the hot water lines inside the boiler, why would they stop leaking after the valve change and start again? The other odd symptom is that the boiler gains water *much* faster when its moderately cold out - we're in Mass, and our warm spell of 30 degree weather had us draining it 2x a day, whereas now that its bitter cold again we can do it once a day. We've just been putting up with draining it regularly, as we were toying with updating the whole thing anyway, so haven't called anyone out again. We are a little baffled at what could be going on here and would appreciate any suggestions.


  • Mark Hunt
    Mark Hunt Member Posts: 4,909
    Could be

    that when the boiler is making steam more often, the heating of the domestic coil swell enough to seal the leak. As the system cools down the leak starts again.

    A pressure test could determine for sure if that is the source of the water. I would not wait to have that done. If it is the domestic coil that is leaking it will only get worse and if it fails completely you could have a major problem on your hands.

    Good luck!

    Mark H

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