Undesired Draining of Water From My Radiators

Charlie Campbell

Background info:

1890's victorian house.

Hot water heat.

Large pipes indicate it was originally gravity-fed.

Now has circulating pump.

Radiator entry and exit points are both on the bottom.

Expansion tank in attic, only one pipe showing (on top).

That pipe goes to a cistern in the basement, not the roof.

System drain pipe drains into sewer pipe.

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I've lived in this house ... longer than I'm willing to admit, given that I've just discovered this problem. After replacing a radiator valve downstairs and refilling most of the radiators, a leak was discovered in one of the upstairs valves (at the stem). Shutting off the water supply to clean up the water and fix the leak, I soon noticed a gurgling sound coming from a few of the downstairs radiators. The water was leaking out! Running to the basement, I discovered that it was going into the cistern, from the pipe that leads to the expansion tank in the attic. In previous years, water had come out of this overflow pipe when I bled the radiators, but that made sense. I figured that the expansion tank filled up and the overflow drained into the basement cistern, i.e., while the supply valve was turned on. Is the water somehow being siphoned out of my [back rooms only, I think] radiators, even though the bleed valves are closed? If so, what should I do to stop it? One way would be to add a fitting to the highest point of the overflow pipe that would make it open to the atmosphere. What do you think? I'm a real novice at this, so I hesitate to go making changes when I might be "missing a piece of the puzzle." This is my first house with hot water heat and essentially everything I know about it was picked up from your site (thanks, BTW).

It occurred to me on that fateful day (this past Sunday) that maybe ... no, probably ... I've had this problem since Day 1 in this house, but didn't notice/comprehend the gurgling occurring after I'd turned off the water supply valve on the previous times I had bled the system. I do know that those back rooms have always been cold, and maybe this is the main reason. I replaced the bathroom valve, for example, because 1.) the radiator wasn't putting off much heat, 2.) I had bled the air out, 3.) the valve was stuck and 4.) the logical conclusion was that the valve must be stuck in a partially open position. Removing it, I discovered that it was stuck in a fully open position. I'm thinking now that if this problem is fixed, I'll probably have real heat at the back end of the house.

Your expertise and help will be greatly appreciated. Thanks.

Charlie

Steamhead (in transit)

Sounds like

the tank filled before you finished bleeding, the water started down the overflow pipe and this caused a siphon. I'll bet that overflow pipe did have a vent at some point, possibly thru the roof, and someone removed it. The vent would have prevented the siphon from forming.

Charlie Campbell

Thanks!! I'll try it.