Finding Leaks

PLUMMbOXED

Well it's heating season and our 1920's single pipe steam system has chosen this year to leak enough that it builds NO pressure. Zero. The house is warm but we're wasting fuel.
The wet returns are entirely visible and they show no leaks. Looking for tips on finding & fixing leaks while the system is in use.

PLUMMbOXED

Ain't she a beauty?

mattmia2

Flood the boiler, fill it to above the top of the boiler and see if water comes running out somewhere.

A mirror will find leaks at valve packings and joints and such but my bet is on the boiler having failed above the water line. If you're lucky it is just a fitting but at the age of that boiler a leak in or between sections is likely.

bburd

How much water are you adding, more than usual? This may be a combustion problem, which you can check by looking at the flame and perhaps clocking the gas meter. An under-fired boiler may not build pressure. The burner may need cleaning.

Check the air vents to make sure they close when steam reaches them, including main vents on the basement pipes if there are any.

Check the supply valve stems for leaks. These can be hard to find, since the steam may evaporate without being visible; but a tissue or your ear may work. Tightening the packing nuts may be enough if they leak, or they may need to be repacked which is usually a simple job.

Look at the top of the chimney outside on a cool day. It's normal for a gas boiler to show some water vapor in the exhaust, but not large clouds of steam unless the weather is very cold.

Finally if you must, turn the heat off, let the system go cold and flood the boiler by adding water just until you can feel the steam riser on top get cold. Then let it sit and watch it for a few hours. Then look around on the floor and inside the combustion chamber for signs of leaks. Then drain the boiler back to normal level on the gauge glass before restarting.

mattmia2

Also what makes you think it is building no pressure? the vaporstat is set to something insane that i can't read so i wouldn't expect it would ever shut off, that gauge isn't a type that can accurately read low pressure, that mercury vaporstat has to be level to be accurate, and have you checked that the pigtail is clear in to the boiler? The vaporstat also has to be perpendicular to the curl in the pigtail so it stays level because that pigtail curls and uncurls some with temp changes.

mattmia2

How often has that been serviced by someone who understands combustion and draft? a conversion burner like that needs to be set up and maintained properly, it isn't like a modern atmospheric burner that will be mediocre under most conditions, that boiler and the vent are all part of how the burner burns in that type of installation.

PLUMMbOXED

We've been in this house 23 years and the system has worked flawlessly till this season. Many thanks for the helpful suggestions and things to consider:
* I'll use a mirror, tissue, and my ears to check fittings, vents and valve packings.
* There's no auto feeder and it's needing only the usual amount of water.
* The firing looks normal (see attached picture). There is lots of boiling and the usual minor fluctuations in the viewing tube. But the gas valve is exposed and could have been bumped to a lower setting. Will test higher setting tomorrow.
* I don't hear any radiator vents or main vents closing (or dropping open), but I think that's because they're not seeing enough steam. Will check this systematically tomorrow.
* No visible steam from chimney or at the "Check Draft" door.
* Haven't flooded the boiler, but there is no visible moisture on, in, or around the boiler.
* Vaporstat is set as always to 1 pound with a 2 ounce differential which (when thermostat is calling) has always turned boiler off at 1# and back on at 14 oz (see attached pictures). The admittedly antique pressure gauge normally reads about a pound at peak. Neither device has moved off zero this season.
* Vaporstat may not be perfectly level but it hasn't been touched and always worked previously.
* Boiler is only shutting off when thermostat stops calling, which could suggest a blocked Vaporstat pigtail. But why are the vents not operating? I think there's not enough steam reaching them and the Vaporstat and pressure gauge are reporting correctly.
* The damper has never been moved since we were here.




Thanks to you I've now a better hit list for tomorrow.

mattmia2

It may be undefiring or not burning properly for many other reasons. That part needs to be done by a professional that understands conversion burners to make sure it is operating safely. Playing with levers and dampers won't assure that.

It is also possible that it is running shorter cycles than normal because of the mild winter

PLUMMbOXED

To mattmia2: Agreed. However, finding a pro that a) knows how and b) wants to deal with this system has been impossible here in Cleveland. My sad experience (going back 23 years) whenever we asked the local heating companies to inspect or tune it up: the guy comes in, sees it, and says "Oh Wow! It's OLD. Better replace it." Maybe that would have served us well in the long run. But being OLD myself, it is repugnant to me. Besides, if we had followed that advice, we might now be going on our second boiler replacement...
I've relied on advice like yours from Heating Help. And we've been comfortable for 23 years. I will search for Cleveland pros again on this site, hoping to find one unlike some who register here without living the values.

Thank you!

mattmia2

there are definitely people near cleveland that know how to set up a burner. look to see who is national comfort institute certified and call them until you find someone who tells you how they will measure combustion and draft and adjust it.

there are many, many people with a van and the ability to fix simple problems, you have to rule those out on the phone.

you can also ask the supply houses for companies to call and ask. the ones that buy the gas power burners would be good ones to try

it would probably work better with a gas power burner but that would have been a better investment 30 years ago and it takes the same skill set to install and set up one of those.

neilc

PLUMMbOXED said:

there's another gage I want @ethicalpaul

Jamie Hall

That gauge is useless. The vapourstat, however, is not -- though it is not correctly set. Using the screw on the top, crank the setting down to 8 ounces cutout. Then take a good level and set it across the top of the box. Then watch the mercury bulb when the boiler is firing. If the pigtail is open you will see the bulb start to tip to the left (and it may tip all the way and shut the boiler off -- that's normal).

Also -- what how much water are you adding?

EBEBRATT-Ed

@PLUMMbOXED

You know your boiler best because you have lived with it for 23 years. If you are not seing pressure on your steam gauge and used to then I would suggest you remove the pressure gauge and vapor stat and clean and blow out all those small fittings that connect the vapor stat and gauge to the boiler. Looks like some of the parts have been taken off or replace before.

Those fittings could be plugged up or partially plugged up

neilc

@Jamie Hall

Jamie Hall said:

That gauge is useless.

so I can have it then, right?

Steamhead

@PLUMMbOXED , if you're near Cleveland, call @gerry gill .

Long Beach Ed

Lots of great information here. If you want to look for steam leaks, and I doubt they are your major problem here, replace the air vents with plugs and pressurize the system with air. You'll find every little leak there is to find.

But follow the recommendations here first.