Tracing a boiler leak
Hello.
I posted something similar a month back, but i’m stumped. I’m losing 1/2-1 inch of water every 4 days, especially when the boiler has been off. When it steams, everything from the header to the main vent seems dry/clean. Joints look dry, vents let out a very small amount of steam in the beginning and then seal. Air vents on radiators are quiet, the valve coming up from the floor also looks dry and is quiet. I did have to repack a few of them a year ago but haven’t had issues since.
After the boiler stops steaming, about 1-2 hours later, the water level is back to the SAME level it was before the steam cycle.
The area around the boiler is dry, the drain valve is not leaking, the gaskets around the sight glass seem dry as well.
The water levels never falls below the bottom of the sight glass. you can look down from above and see the water level. but looking at the sight glass it will be dry.
Is this likely a wet return leak?
Comments
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It could be a couple of things, the 'small' amount of steam released by the vents may be more than you realize, or it could be a leak in the wet return, especially if it goes unedr the floor, or there could be a pinhole leak in the boiler casting and steaming up the chimney. To test for this you want to turn off the boiler and fill the boiler until the water level is going up the riser(s). Let it sit for a couple of hours and look to see if there is any water dripping onto the burbmners or floor. Also look to see if there is any rust spots on the burners.
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how long typically after the sight glass is full to when the risers fulll? i’m terrified of sending water up the radiators, it’s happened to me once . never again
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This is done with 180° water in the boiler. the main pipes will be cold. the boiler risers will be cold to the touch. with the burner operating and the water at about 180° start to fill the boiler above the sight glass. (caution You dont want to make any steam) as the hot water rises in the boiler, feel the boiler riser pipe(s) than the header than the riset to the system main. Once the hot water gets to the top of the riser and starts to go into the main, close the water feed valve
Even if you can't see thru the pipes, the radiation from 180° water will see thru the pipe.
Edward Young Retired
After you make that expensive repair and you still have the same problem, What will you check next?
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I was not yet able to do as advised with the water test, there are some questions that come to mind. My gf who’s watching my house at the moment said the house warmed up nicely this morning, cold to comfortable in about 35 minutes. She was able to tell me that the thermostat was satisfied just before the pressuretrol “snapped”. After the boiler cooled she was able to send me a picture of the sight glass and it was lower than how i left it yesterday. I asked her to mark where it was and to send me another picture later. She was able to and the level dropped again, very very slightly.
I suppose my biggest question is, since the boiler is building pressure and warming the house comfortably in under 40 minutes, is it less likely to be at the boiler? or there’s really no answer?
When i return home i will try filling the boiler as suggested, but for the meantime im trying to draw an idea of the best places to check.
I’m 98 % sure i have a leak below the waterline because in the summer the water in the sight glass slowly disappears over the course of a month. However i’m unsure if that leak is causing the water loss in between steamings
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You may well have two leaks. Or more… the summertime one pretty well has to be in the boiler or wet returns — and if it drops below the Hartford Loop, it has to be something about the boiler (but mind that it could be a slowly dripping drain valve, rather than the boiler itself). Otherwise my money would be on a wet return.
The loss while steaming is more likely a steam leak — but tracking it down may be difficult. Before condemning the boiler, though, make sure that none of the radiator valves (or vents, if it's one pipe) is leaking steam, and check the main vents. A steam leak like that can be amazingly hard to find.
Br. Jamie, osb
Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England0 -
am i able to see if it drops below the hartford loop? all i can see is it drops to just below the sight glass. not any lower. you can see from the top if you look down at it. but not from the front.
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you could make a water gage with about 10 feet of clear vinyl tube connected to a hose repair kit, attach to a low boiler drain, suspend tube over pipe at ceiling, and open drain, water in vinyl will match boiler level,
caution, boiler at higher pressures will blow water out open end,
known to beat dead horses
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One steam boiler leak I found was on a dripping drain valve.
The owner had run a garden hose connected to the boiler drain, across the basement to the floor drain……never could see the dripping.
Probably not your case though.
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Do you have wet returns run under the basement floor??
If you do that is the first suspect and most common area to get a leak
Set the boiler at a normal water level and mark the gauge glass and shut the boiler off and leave it overnight. If it (the water level) drop over night and you don't see water around the boiler then the wet returns are leaking.
Next step is to fill the boiler with water up above the top of the boiler. With the boiler shut off start adding water until the supply pipe coming out of the boiler gets cold then stop adding water. Leave the boiler off overnight or at least for a few hours and check for leaks.
Drain the boiler down to normal before starting it up. You will not get water in the radiators.
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yes, it seems the returns start from the main vent (i think??)… after the main vent theres a pipe that goes down and then i don’t see it anymore. the piping near the boiler is dry.
when i get back im going to try and run the boiler and check each radiator and joints in the piping. going to try what has been suggested
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sadly it does appear that the boiler has reached its term. i added water until the pipe coming out of the boiler got cold as suggested. i didn’t see water on the floor but i saw water dripping down onto the burner. it looks like it’s leaking dead center. :(
didn’t think it was possible since it heats quickly and builds pressure.
so it seems as if i have leaks in the boiler it’s self and the wet return since the water level dropped albeit slightly, microscopically in 18 hours of not being used
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Hello Frankfog!
My steam boiler had a similar ending. Since it was the middle of winter, the company who was going to replace suggested i “baby” it until the warmer months. I installed a new LWCO for safety, added water as needed, and in most cases shut it down at night and only ran it when i was awake. idk if this is an option for you, but of course dont do anything without an expert opinion
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@Frankfog2 If your boiler is indeed leaking it might be a good time to get a professional in to assess the extent of the leak. You need to make sure your safety controls are 100% up to the task! The drip-drip could become much worse and the last thing you want is for the boiler to dry fire.
Many have limped along until the spring. Some thoughts if it is indeed safe to do so:
- Set the pressuretrol to as low as you possibly can, if you haven't already. Less pressure is good when you have a leak, and in general.
- Don't do setbacks. Keep it at a certain temp and forget it. Running full blast and potentially cycling on pressure is going to potentially make it leak faster.
- Let it live its easiest life right now. Keep the thermostat temp as low as you can tolerate for the winter.
- Check that water level like 10 times a day!
- Buy some Oil Filled Electric Radiators. They are the safest type of space heaters. Make sure you don't overload your circuits.
If the pro's agree the the boiler is toast…perhaps some "Boiler Stop Leak" will help for the time being and get you through until spring.
And don't just call up your local random HVAC company, they will tell you that your boiler is junk even if the only problem was a scratch in the paint. Find someone on here. Where are you located?
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It's done. but I like @AdmiralYoda 's approach. So long as you can keep enough water in it, you'll be fine — and since it is already done, adding fresh water all the time won't hurt it any more, and it won't hurt the rest of your system at all.
But. Please do check your low water cutoff. Do you have an automatic feeder? If so, keep an eye on it. If not… check that water level every time you think of it. Good exercise!
Br. Jamie, osb
Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England0 -
much appreciated to you, thank you for taking time to share your thoughts, if i may i have a question for you or any expert on here.
why does it seem like the water seems to drop faster once it reaches a certain point on the sight glass? After the flood test, i dropped it down to a safe level and fired it up, it’s been steaming a lot due to the cold weather today, it’s been off for an hour and the water is exactly the same as how i left it. It’s something i’m not fully understanding. if it helps the water is on the higher end of the sight glass. about 2 inches from the top
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When the system is running hard it is normal for the water in the site glass to go down a little bit. Not much, but a little…maybe a half inch? The steam condenses in the radiators and the water travels back to the boiler. If the radiators are full of steam there is a decent amount of condensate traveling back to the boiler.
Another reason for the site glass water to go down during a heating cycle is the condensate return get partially clogged so the drain slow. Water gets backed up into the return line, causing the site glass water to go lower, and then slowly returns after the heating cycle is complete.
Did we get a definitive answer on the wet return? Do any of the pipes connected to the system go under the basement floor and come back up above ground closer to the boiler? These are notorious for rotting out over time and losing water into the soil. Pictures will help!
I'd seriously recommend contacting one of the pro's from this site. Where about are you located?
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i am from Long Island NY, i found a Pro on here i intend to call after thanksgiving.
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If it is dripping on the burners it is probably toast. Have a pro check it it could be leaking from a pipe fitting under the jacket but doubtful.
get someone who knows what they are doing, get the right size boiler and do your research.
Sorry you have to go through this during the winter.
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