Is my steam boiler really leaking?

Gary_24

I have a Weil Mcclain 125k BTU steam boiler on a single pipe system in my home. I have lived in this home for over 6 years and was told the boiler is approximately 20 years old.  I have not had any problems with the boiler. Recently, a boiler servicer came to do pre-inspection for a maintenance service plan they offer and told me that my boiler has a leak and therefore cannot give me the service plan; he stated that i need a new boiler system. ( he did say i might be able to get by another season with this boiler) He "showed" me steam escaping(using his eyeglasses to fog up) out through the top cover panel around the opening cutout for the pressure relief nipple and valve in the rear corner on the top of the boiler.

The next day i removed the top cover, fired up the boiler and after several minutes steam began to condense on the of the side 7" nipple and rolled down along the nipple forming a pea sized drop on the base where it threads into. The "steam" does appear or feel to be coming up from behind the boiler rear cover or the vent box(attached to the back and top of the boiler) and condensing on the cool steel 7" nipple. I then replaced the 7" nipple with a new piece of pipe to be sure it wasn't leaking up through the threads; still have the same issue. I don't have enough clearance to remove the rear cover panel for an inspection. I have never noticed any water at all on the floor and usually have to top-off the boiler(manual feed) approximately every 7-10 days.

How do i know whats really going on here? Is it normal for some "steam" or water vapor to rise when a cold boiler is first fired up since it's full of cool, basement "room temp" water?

Steamhead

Could be either a leak

or moisture in the jacket evaporating.



We usually fill the boiler well above the waterline to test for leaks, since often the leak is actually up that high. If no water appears on the floor or in the firebox, the boiler is probably OK.

Gary_24

testingboiler for leak

Thanks for your reply and advice. Do you fire up the boiler after overfilling it or just fill, check for leak and then drain?

Joe V_2

under pressure

will yield for the fastest results.

Joe V_2

under pressure

will yield for the fastest results.

Steamhead

We just overfill it

if it has the usual rot above the waterline, you'll see water. 

Gary_24

Under Pressure

So i should fire it up while it's overfilled and check for leaks?

Jamie Hall

Don't need to fire it up...

in fact, better not -- you will get all kinds of water in your steam pipes and it won't prove anything (and probably bang like crazy).  Just let it sit for a while and check for any water in the firebox or around the base of the boiler outside.  If you fill it over the gauge glass top, the leak -- if any -- may or may not be low enough to bring the water back down to the gla, so that's not necessarily helpful.  However, do remember to lower the water level back to the normal water line before you fire it up again...



If you have an automatic water feeder, does it have any way to indicate how much water it's adding?  That's a very useful ongoing check

Gary_24

Leak check

I don't have an automatic water feeder. I opened the relief valve which is on an 8" nipple on top of the boiler, turned on the manual fill valve and filled it until water came out of the relief valve. After several hours i did not see any water on the floor; i left it overnight and will check it again this evening.

Rod

Wait a while.

I would even wait a day or two (48 hours)  and see if a leak develops. You might also want to check your return piping to the boiler to see if any leaks develop. Does any parts of your return piping go underground or where you can't observe them for leaks?

- Rod

Gary_24

waiting for leak

It's now almost 24 hrs since i overfilled my boiler and no signs or evidence of any water leaking on the floor around my boiler; it's bone dry. My return piping is all above ground.  i was told my boiler itself is leaking and so far I'm not finding this to be true.

lchmb

look inside

Look in the view door to the boiler and see if there is any sign's of water present in the chamber also...

Gary_24

View door??

Does a gas fired boiler have a view door?

Rod

Check the bottom of the boiler

What you are trying to accomplish is to inspect the bottom of the boiler for leaks. If you aren't oil or power gas you most probably don't have a view door. However there should be a panel you can remove and with a flash light and possibly a mirro,r check for wet stops on the bottom of the boiler above the burner. Also check around the burner pan for drips.

- Rod

Gary_24

inspect for leaks

It's natural gas fired boiler, Weil Mcclain. I overfilled the boiler almost 2 days ago and have checked it completely from every side and angle and there is not a drop of water anywhere.  Does any company make a U/V leak detector fluid kit like we use on automobiles to check for fluid leaks?

Dave in QCA

Another possibility

I have seen on numerous occasions, the phenomena that you describe, even on a hot water boiler.  These boilers did NOT have leaks in the boiler castings.  The leaks that existed were very minor leaks between the castings and/or where the draft collector was attached to the top of the castings.  As a result, a VERY small amount of flue gasses were finding their way in the the space between the boiler block and the sheet metal jacket.  These gasses will migrate upward and escape at any opening in the upper part of the jacket.  Nat gas exhaust has a much higher water content than fuel oil, so the vapor condenses on anything cold placed in the pathway.



If I were you, I would make sure that I have a good working CO detector in the house, just in case the leak is a bigg issue, which it probably is not.  I would forget about the service plan.  Those plans are designed so that the company offering the plan wins, not you.  You probably have several more years of usueful life in your boiler, and I would ride it out.  Take good care of the boiler, watch it close, and perhaps, start your own savings fund for its future replacement.

Gary_24

Probable Possibility!

Your's is the reply i have been waiting(and wanting) to hear. This is along the lines of what i have been thinking but not able to put into words myself! I believe your theory is correct and is what is happening in my situation since i don't see any evidence of an actual water leak and also the "steam" leak the service guy was trying to "sell" me was happening way too soon after firing up the boiler--not enough time for the boiler to even begun having boiled water and make steam!

 I will try to prove your theory by dropping 1 or 2 Trace-A-Leak Fluorescent Green Dye Leak Detection Tablets into the boiler through the relief valve nipple, then firing it up and checking for leaks.

Can i caulk around the sheet metal draft collector box, where it fits on top of the boiler, with Fireproof caulking to try and seal it better. I do have CO detectors in the house and have never had them go off.

THANK YOU

lchmb

sorry Gary

Didnt realize your's was a gas system....