Boiler needs constant refilling

LoudonFrank

Folks,

I have a single pipe steam heating system. Nothing has been changed in the system in the 15 years I have owned the house. However the boiler needs to be refilled (reaches low water cut-off) about every 48 hours during heating season whereas it used to need topping off about every 2 weeks. This has happened gradually.

The house has 16 radiators, some fed off a loop around the basement and some off of branches, one branch off the header and the other off the loop at the start of the loop. All radiators have HeatTimer Varivalves set to open. The radiators all get hot at about the same time meaning to me that the valves open when cold. One or two will show a LITTLE steam if the furnace runs for a long time like when raising the house temperature in the morning.

I just replaced the main valve. It does not get warm or vent steam, but since the radiators start getting warm about 6 to 8 minutes after the burner starts, I think it is letting the air out of the main piping. The second picture shows the main vent as that little bright spot right at the top middle of the picture. It is the only main line vent.

The Pressurtrol is set to .5 with a differential of 1. The 1 - 30 pressure gage never moves, so I don't think I have high pressure.

The system is quiet. No boom, bangs, reverberations, etc. Nothing to indicate wet steam.

Could I be losing that much water through the radiator vents without a lot of visible steam?

I see no signs of leaks in the pipiing or where the piping goes into the radiators.

Any suggestions where the water is going?

I don't like having to fill the system so often and it makes it difficult to be away for more than one day visiting grand kids etc.

Any suggestions? Thanks



Frank

nicholas bonham-carter

mysterious water disappearance

where could it be going? can you see steam coming out your chimney, when the boiler is firing?

can you switch it off, and let it cool, then overfill well above the top of the boiler, and look for leaks into the firebox?

are there any buried returns which could have sprung a hidden leak?--nbc

LoudonFrank

Leak into firebox?

Nicolas,

Leaking into the firebox is something I had not considered. I do notice quite a bit of surging in the sight tube when oil burner is firing.

Don't think there are any leaks although some of the piping goes thru crawl space and is difficult to see, but the dirt looks dry.

Not sure how I would tell "steam" out of the chimney from smoke. Can you help me there?

Any more detailed suggestions on how to see if the boiler is leaking into the firebox?

Thanks

Frank

BobC

White smoke

Steam in the firebox usually signals itself by a nice white plume coming out of the chimney when the boiler is firing. usually all you see is some heat distortion except in very frigid weather when you might see just a bit of white.



Your sight glass looks a bit murky, maybe the boiler needs skimming, that would not fix water usage though. Also that main air valve is probably too small, how long is your steam main?



Bob

crash2009

I was just reading your last post.

 How long ago did you put the Heat-timer Varivents on the radiators?  Any signs of water staining around them?  This probably won't account for the amount of water you are losing, but its worth a look.

LoudonFrank

Steam Main

The loop around the basement is about 100 feet total and drops about 10 inches. The two branches which start pretty close to the furnace are each 25 feet or so. The loop actually comes off one of the branches and loops around while the branch feeds 3 radiators. The other branch feeds 4 radiators. The rest of the radiators feed off the loop.

So the vent is at the start of end of the loop. The vent might be too small, but the behaviour has changed over time so the vent size does not explain it. There is only the one main vent.

I will watch the chimney the next time the boiler fires.

I guess I will have to do some research on what skimming is and how to do it.

Frank

LoudonFrank

Heat Timers Vent

They have always been there (the 15 years i have owned the house). I replaced a couple that were clearly bad. the others appear to be working fine based on how the radiators warm up, etc as noted in my first post.



Frank