Steam boiler excessive makeup water usage

Synbio

One-pipe residential steam boiler. Water needs to be fed every 2 days or low cutoff gets engaged. It seems way too frequent, it should be what, topped off once a week?

• checked chimney while boiler was running on a cold day, no visible steam.
  
• half air vents are new, no visible steam coming out of any
  
• no visible leaks throughout the unfinished basement
  

I know I need better insulation on the pipes but other than that I don't know any other improvements I could make.

Jamie Hall

You have a leak. A gallon a month is more like it. However, it is not a large leak or leaks -- and may be astonishingly difficult to find. Remember that a drip every ten seconds is a gallon a day! I would look again at all the valves to make sure that the packing around the stem isn't leaking. Check the vents again -- you won't see the steam, but a tissue held up to the opening after they are supposedly closed should stay dry. Check all the connections you can find -- it's not uncommon for there to be a small leak, which you will only see by staining as again the water will evaporate right away.

KC_Jones

Synbio said:

One-pipe residential steam boiler. Water needs to be fed every 2 days or low cutoff gets engaged. It seems way too frequent, it should be what, topped off once a week?

• checked chimney while boiler was running on a cold day, no visible steam.
  
• half air vents are new, no visible steam coming out of any
  
• no visible leaks throughout the unfinished basement
  

I know I need better insulation on the pipes but other than that I don't know any other improvements I could make.

If you are saying how often to just keep it off the low water cutoff I'd say once a month at most.

EBEBRATT-Ed

@Synbio

do you have any return lines run under the basement floor?

Synbio

EBEBRATT-Ed said:

@Synbio

do you have any return lines run under the basement floor?

Not that I know of. What's a return line for?

jhewings

The return is the pipe(s) where the water returns to the boiler after condensing from steam in the radiators and pipes. Sometimes the return goes under the basement floor where they eventually leak or become clogged. It is preferable that the returns do not go under the floor.

Since you apparently do not have big obvious leaks than you probably have little leak(s) which can add up to a lot of make up water. Check all of the valve stems and union nuts at the steam valves of the radiators. Look for small amounts of water escaping (while the boiler is steaming). The water could easily be evaporating without reaching the floor. If you find some like this, they might be fixable by tightening the packing nut at the valve stem or the union nut. If this doesn't work you might need to repack the valve stem. Also look for radiator and main vents which might be leaking steam. Look for rusty colored dribble marks on your pipe fittings, especially unions.

I suggest you pick up a book or two to learn about your steam system.

https://heatinghelp.com/store/detail/we-got-steam-heat-a-homeowners-guide-to-peaceful-coexistence

https://heatinghelp.com/store/detail/the-lost-art-of-steam-heating-revisited

Synbio

Return lines are definitely up high in the basement, nothing under the floor. The basement is unfinished so I've been able to track almost all the pipes going to/from the radiators.
I guess the leak will be more subtle than I realized.

ethicalpaul

Or there's a hole in the boiler and the water is escaping as steam up your chimney

jhewings

If you want to rule out a leak above the waterline, which results in steam going up the chimney, and excessive make up water, the surefire method is to fill up your boiler full with water. If there is a leak above the normal waterline, then the floor will get wet.

Synbio

ethicalpaul said:

Or there's a hole in the boiler and the water is escaping as steam up your chimney

I haven't seen steam up the chimney. I had it running and went outside on a cold day.

Synbio

jhewings said:

If you want to rule out a leak above the waterline, which results in steam going up the chimney, and excessive make up water, the surefire method is to fill up your boiler full with water. If there is a leak above the normal waterline, then the floor will get wet.

Has that ever worked for you? Do you think the leak would be significant enough to notice right away or is it more of a slow trickle?