the mystery of the disappearing water

JoeT21

For over a year now, I've had to refill my steam boiler too frequently. It used to be I'd have to add a small quantity of water only at the start of the hearting system. Then it got to be that I'd have to add water every day. There is no steam leaking out of my radiators -- that I know for sure. I have an old Fitzgibbons boiler in my home, the plate on the front says 1926, It now runs on natural gas. Finally I was able to detect and fix a small water leak that would develop when the boiler was producing steam. The leak was from an exterior valve on the boiler that went nowhere (it's not even clear to me why that valve is there). I had the valve replaced with a cap. This improved the situation but didn't fix it completely. Then, a few weeks ago I addeda small amount of water at night and in the morning I could hear the water hammering. Some of the radiators were cold that normally work great. I saw from the sightglass that the water level rose beyond the sightglass level and there was even some water on the floor. I then starting draining water from the boiler ---- I drained about 20 gallons before the water level in the sightglass was at the half-way mark. It seems that a possible reason for my having to frequently refill the boiler too often is that some of the water was not returning. I should add that I do not have an automatic water fill on the boiler; whenever I add water I do it by manually opening a valve. There is a large vertical pipe next to the boiler which says Trane on it. This is the condensate receiver, I'm guessing? Could something be plugging up the receiver? Any helpful advice would be appreciated.

Jamie Hall

First off...

check your pressuretrol or vapourstat.  If this is a Trane system, the boiler cutoff must not be above 1 psi and preferably somewhat lower.  Excess pressure will back water out of the boiler and into the returns, which could be part of your problem.



That said, 20 gallons of water extra is a lot; unless you have added that much very recently on purpose, for it to have accumulated over time is a little strange.  So you might check that your manual fill valve isn't leaking.  Also, if there is a domestic hot water coil, you should check that that isn't leaking, either.

nicholas bonham-carter

overfilling a trane

is this a 1-pipe system, or 2-pipe?

the only place where that amount of water can hide would be in the radiators, on a 1-pipe system, because of the radiator valves being almost shut, but not quite [they should be always open].

20 gallons of excess water is a lot, and if you have a hot-water coil in the boiler, i would suspect that first

some pictures of the radiators,along with the boiler would help in diagnosis. --nbc

JoeT21

Thanks for the replies

This is not a Trane system, the boiler is an old Fitgibbons. There is a vertical pipe that says Trane on it, which I'm not completely sure what it does. What I suspect is that it some kind of water storage system for the return pipes so that the water doesn't immediately re-enter the boiler. Does that make sense? (I'm clearly not a professional.)

Also, there is no domestic hot water coil -- I have a separate water heater. I'm pretty sure that the manual fill valve is not leaking. The radiators are 2 pipe.

I think checking the pressure is a good idea -- I'll do that. Is it possible that the water builds up in what I'm guessing is a storage pipe until the pressure is high enough to overcome the pressure in the boiler. And that is the reason why the water in the boiler overflowed?

Jamie Hall

the make

of the boiler isn't really relevant -- "Trane system" refers to the various devices on the radiators and piping, and the receiver and it's appurtenances as well.  Boiler could be anything.  The water in any two pipe system should just run back to the boiler, almost immediately -- it doesn't get stored anywhere.  Unless something is badly amiss.



But yes, it is quite possible that if the boiler pressure is too high, the water will back out of the boiler and "hide" in the returns -- or possibly even in the radiators, if the pressure is high enough.  Remember that for each psi of boiler pressure, the water level in the returns will rise 28 inches.



Still and all, 20 gallons is an awful lot of water...

Steamhead

Fitzgibbons just made the boiler

the "vertical pipe" is probably a Trane Direct Return Trap. You probably have a Trane Vapor System. Your radiators will have two pipes connected to them, rather than just one, and Trane valves and traps.



The water probably came from one or more vents at the ends of the dry (overhead) return lines.



It's possible that the DRT has failed, allowing steam pressure into the returns, which would keep the water from returning. If you control the boiler pressure with a Vaporstat, the DRT really isn't needed anymore.

JoeT21

Trane trap

Thanks again for the replies.

Can someone explain to me what the purpose of the Trane direct return trap. What is it supposed to do and how does it work? I couldn't find much on the internet.

Buergermeister

Capped valve

Hopefully that valve that was capped off was not the Pressure Relief Valve.  I would suggest you take a few pictures of the near boiler piping especially the general area of the boiler, the piping and area that the valve was at that you capped.  If this was the Pressure Relief Valve it is an extremely important safety device.

JoeT21

Some photos and some more questions

I've attached some photos of my Fitzgibbons boiler. This is for a single family home. You can see two valves in the first photo. The top one is the one that was leaking when the boiler was making steam. I replaced the valve with a cap. That decreased some of the disappearing water, but not completely. Does anyone know what this valves ever did? They certainly don't seem to be doing anything now.

Yesterday I tried to figure out if some of the water was hiding out in the radiators. The boiler had been running for about 2 months and I had kept the water level in the middle of the sightglass. I drained the boiler and measured almost 30 gallons. I then refilled the boiler until the water level was again in the middle of the sightglass and drained it again. I came up with the same amount. How is that possible, is that really the capacity of the boiler, why do I need so much and is it all going into the boiler? I estimate that maybe 1 gallon or so of water is actually being converted into steam (by noting the drop in the sightglass). What is all the other water used for?

Also, in one of the photos you can see the Trane DRT. What does it do and how does it work? 

Steamhead

The leaking valve is a "Try-cock"

it was a backup to the sight glass. If you open the top one and get steam, and get water from the bottom one, you know the water level is between the two.



The DRT is different from the ones I run into. This one has the dry return vent mounted on top, instead of separately. Can't make out the lettering from the pic, is it really a DRT or just an air trap?

JoeT21

DRT or something else?

Thanks for the reply. I don't know if this is a DRT or not -- I was hoping you could tell me. Here's what it says -- although some of the lettering is hard to read

TRANE

PATD

No 1

CAPACITY

400 TTS

I'm not sure about the S in TTS however.

Steamhead

Is there

a pipe leading from the steam main to this thing? 

JoeT21

It's the return to the boiler

You can see the white painted pipe in the photo on the bottom left, leading into the boiler. The pipe all the way to the left in the photo is the return from a loop that circles the basement. The pipe in the middle is the water feed.

JoeT21

suspicion where my leak is from

Today it was 20 degrees outside, noticeably colder than the past couple weeks. When I left this morning I looked up to the chimney and I could see the vapor trail. Should I then conclude there is a leak in the heat exchanger. Remember this is a 1926 Fitzgibbons, probably original to the house. Should I have someone inspect the heat exchanger?

nicholas bonham-carter

leaky fitzgibbons

the method of testing for a leak in the boiler is to overfill the boiler above the top, when only warm. let it sit for a while with the switch off, and any leak should show up with a drip onto the floor.

if you haven't already done so, add up the edr of your radiators, so the steam pro will know what size boiler to install [not the old boiler capacity, or the heat loss of the house].--nbc

JoeT21

why overfill?

I don't understand why one needs to overfill to boiler. How does this tell me if water is going up with the exhaust? Please be explicit.

I realize I may need to buy a new boiler -- what do you think of Dunkirk, Burnham or Bryant? Anything in particular I should avoid?

Steamhead

It's not a DRT then

just an air trap.



The vent in the top of this device is probably too small for use with oil or gas firing- I'd suggest a Gorton #2.



If you over-fill the boiler, and there is a leak above the waterline, water will come down into the firing area. Then you know you need a boiler.

nicholas bonham-carter

Leak detection

Over-filling the boiler will establish without a doubt the presence of a leak, and perhaps show its location in the sections.

A competent installer will want to know what sort of leak there is, and why it happened in order to prevent a reoccurrence.--nbc

Unknown

Leakage detection

Well There are so many reasons by which Water is leaking from the boilers as the acid rain is one of the major factor that is being cause rust on the pipes that leads to the corrosion and which causes weakness of the pipes that results causes leakage.In that case we must call the plumbers immediately otherwise it will cause heavy loss of water.

http://www.allkaregroup.co.uk/leaking-pipes-repair.html