One-pipe system going through a ton of water

DeeJay3

Hi. I have an old one-pipe steam system and a new boiler. I turned off my auto-refill switch last year (can't recall how or why) and since then my system has worked great. It used to take a good five to seven days of very cold weather for the system to go from "full" to "empty." Now, I need to fill the system every other day.

Can anyone suggest why my system is going through so much water?

Thanks.

Doug in Connecticut

Jamie Hall

It is vaguely possible that one or more of your vents is not closing properly. You would likely notice this as excess humidity in the affected room; if it were a main vent, of course, it would be in the basement.

However... the most likely suspect is a leak. How old is the boiler? Even though it is relatively new, it is possible for it to have developed a leak. On a nice cold morning -- such as this one -- go outside and look for a plume of steam from the chimney. Not just wisps, but a real plume. That would be a leak above the water line. Leaks below the water line you would likely notice as dampness, but check thoroughly.

Another source of leaks is wet returns, if you have any. Check them thoroughly.

DeeJay3

Thank you, Jamie.

I've checked all the vents and they are clear. However, another symptom is the vents used to create a slew of sharp hisses (blowing out hearing in my left ear, btw) and that is not happening this year. I'm not complaining about the lack of hisses, but that symptom might be a clue as to the root cause of the problem

I checked and there is plenty of heat but no steam escaping from the chimney.

I don't see any excess moisture beneath or around the furnace and the main vent seems to be okay, i.e., the system is heating and it is not venting.

Jamie Hall

Well... that's more water than the system should use, by a good margin, and it simply has to be going somewhere. That said, finding out where it's going can be really difficult, as steam escaping into a heated space is invisible.

First, check and make sure the pressure is OK -- no more than 1. psi. Then go around to each vent (including the main) when the system is operating, and check for any moisture escaping -- a cold mirror works well.

Abracadabra

check for underground returns or return pipes running thru a brick firewall. If you have any, it's a good bet they are leaking there.

DeeJay3

Jamie--I boosted my pressure last year to 3 psi. That was to correct a nagging issue, which had water seeping out of the lowest radiator on the coldest days and a lot of knocking.

I have 3 second-floor radiators and 7 first-floor radiators. All of the second-floor radiators are emitting moisture and at least one of the first-floor radiators is (some are only emitting vapor sporadically as they are all hot.

BobC

3 PSi is really too high but I doubt all that water is leaving through the vents, you have a substantial leak somewhere. My 95 year old system is not as tight as it should be and I add about 1/2" of water every 3-4 weeks.

Bob

DeeJay3

Bob, thanks. The only part of the system I can't eyeball is in a crawl space under the kitchen. I should pull the insulation and check there, right?

BobC

Yes, that leak has to be fixed or it will destroy your boiler.

What pressure is the boiler set to operate at? It should be less than 2PSi (hopefully less than that), your statement about the load hissing before leads me to believe you were operating at higher pressure. One reason the noise stopped my be because it's blowing out of a leak somewhere.

Bob