New boiler using excess water

jeffg

We have replaced the original coal converted to oil steel tube boiler in our old 1910 5500sq ft house to a new Smith GSX288 atmospheric gas boiler. We filled/started the boiler five days ago and it works fine, except that it has tripped out on the LWCO twice now and I have added a total of 15 gallons to it. We don't have any underground or hidden piping and I don't see any apparent leaks. I am completely new to steam boilers, but this seems very excessive to me. Any ideas where we could be losing water or what to check on the system?

Jamie Hall

It is wildly excessive. Something is seriously wrong there. Did the system you replaced need water from time to time? If not, it's clearly a problem with the new boiler.

Get whoever installed the boiler for you back, right now, to find out what the problem is. If the boiler came in sections, I'm sort of thinking that it wasn't assembled properly.

nicholas bonham-carter

Possible causes of excessive water use:
Leaks in underground condensate returns.
Steam leaks through radiator, and main air vents, valve packings, or
Holes or cracks in the boiler sections, (unlikely in your case).

Causes of “phantom” water use, where the water eventually returns, leading to an overfilled boiler:
Dirty water due to lack of proper skimming boiling improperly, and throwing lots of water up into the supplies.
Clogged wet returns
Wet returns now higher than the boiler waterline causing water to hide due to pressure differences.
One-pipe radiators with partially closed inlet valves, filling up the rads.
Keep the pressure down as low as possible.—NBC

jeffg

@Jamie Hall - The original boiler was dead when we got the house, so we dont know how it worked. The new boiler came assembled and isn't leaking(no water around it). I am the installer; this is my first experience with a steam system.

jeffg

@nicholas bonham-carter - We dont have any underground or concealed piping. I replaced the main vent with two Big Mouth vents. I can hear the condensate running down the return, on startup and I have water at the drain, below the Hartford loop.
The wet return is spaced according to manufacturer's instructions. All of the radiators are heating normally and I havent seen water around them, etc. The system hasnt ever registered pressure on the 0-15 gauge that came on the boiler.

KC_Jones

You need to find leaks or possibly a plugged return. Did you flush all the wet returns and or replace them during the installation?

Remember steam is invisible so you might not be able to see leaks. Check valves, unions, vents etc., use a cold piece of metal or a mirror, if you get condensation you have steam.

Is this a 1 pipe or 2 pipe system?

Jamie Hall

Sorry -- didn't realise you were the installer. Frustrating, isn't it?

It's worse when the original boiler was dead.

OK. Going to be a bit more detective work here. To a one of @nicholas bonham-carter 's points. Wander around the whole system and really identify what pipes were supposed to do what. What you are looking for particularly is any returns which are above floor level. There are two kinds: dry returns, which will be up overhead somewhere, and wet returns. The wet returns usually are near the floor -- but not always, particularly towards their far ends. They can be booby traps on a new install, as they are intended to be full of water -- below the boiler's working water line -- at all times. Newer boilers, however, are shorter than old ones, and sometimes what should have been below the water line isn't any more. If you find that, it will need fixing.

That still leaves the excess water use, and it really is excessive. I would double check the boiler. Even if it came assembled there is a possibility that there may be a leak between sections. You won't likely see any water lying around anywhere, as the leak may be above the water line and the steam may be going into the fire chamber and thence up the chimney. The way to find that in this weather is to go outside when the boiler is working and has been for a while, and see if you see billowing white "smoke" from the chimney. If you do, not good. If you don't, be happy -- that's not the problem!

Don't expect to see pressure on the supplied gauge. That's there to keep the insurance people, the building inspector, and sundry others of that ilk happy. If you want to see what the boiler is really doing (and it's not a bad idea) get a 0 to 3 psi gauge and put it on the same pigtail as the pressuretrol.

And keep looking -- that water has to be going somewhere.

SeymourCates

@jeffg

Without any obvious leaks, the issue is typically a relatively low volume available for phase change to steam relative to the size of the system. It's quite common with the new boilers and it has nothing to do with leaks and it has nothing to do with plugged returns. You can confirm this as follows:

Make a note of the waterline on the sight glass. Mark it with crayon. Be sure the level is at least 3/4 of the way up on the glass. Operate the boiler until the LWCO trips. (may take at least 45 minutes). Do not add water. Wait for 15 minutes. Now make a note of the level in the sight glass and compare to original level. If the level returns close to the original level, the problem is insufficient volume available. There are a few tricks to overcome this situation should it be confirmed.

midiman143

@SeymourCates

Great info semour, but if that was the case wouldnt the system hit the low water while running instead of hitting the LWCO after days of use? AKA the water level is dropping off over time vs a rapid drop off. Am I understanding this concept correctly?

@jeffg
may want to take a look at my post earlier about losing water as I have the same issue, and still due but its much better. Alot of test ideas thrown around to help diagnose your issue.

Kahooli

Was this the first time this system has been run in a very long time? 5500sqft house, lots of pipes and radiators - maybe you just have 15 gallons of condensate now sitting in the radiators. And if the boiler was shot, it's a good guess that many air vents are shot too. Leaking air valves on a system that large can lose a lot of steam too with how cold it's been.

MilanD

Hmm, well, did you pressure test the boiler with air after the install to make sure it's tight? Probably not, and why would you - it came assembled from the distributor. I wouldn't either.

As it was said above, there may be bad casting (not likely) or seal that's leaking in the fire chamber above water line that won't be seen and will go up the chimney. Fill the boiler with water above the takeoff (making sure it's cool to touch before adding fresh water), then see if it drips anywhere. I had something like 13 gallons make-up on our 2000 edr boiler over 3 days on a pin-hole leak no bigger than a pencil eraser. Flooding the boiler found it right away. For what it's worth, I could hear the boiler sounding like a kitchen faucet when it was steaming with my ear close to the draft hood. If you hear the "shhhhh" sound there, that would be a tell-tell sign too.

Was this house empty for a while and not heated a few seasons? It may be likely your packing around inlet valves dried up and is slowly letting the steam out through the valve stem. Again, you don't need much of a hole for a lot of steam to escape, and a few of those or a few vents not closing, with cold weather we had and boilers running a bit more, it's all it would take. Get the system going then go around with a mirror or a piece of glass and place it over the vents and valves, under rad unions. Some small water leaks on radiator unions can also evaporate on the hot pipe as they leak before they show up as a wet spot on the floor. Again, a few of these around the house and it's all it takes. Ask me how I know.

A steady drip over 24 hours will leek out a surprising amount of water. Check all your exposed joints be it fittings or radiator connections.

Frustrating, I'm sure.

Fred

That works out to a pint of water per hour, if the boiler ran 100% of the time. Assuming, in this weather, the boiler runs about 50% of the time, that works out to about a quart per operating hour. I would be looking for :
1) a Main vent that isn't closing
2) a couple supply valves or radiator vents that are leaking/steaming
3) a pipe coupling/fitting that is leaking/steaming Are your mains insulated? If so, a fitting could be leaking and steaming away with no obvious stain on the outside of the insulation. Do you have any flange joints on the old mains? They have gaskets in them that deteriorate, over time, leak and the small leaks actually steams away without notice.

jeffg

OK, since this discussion, we have:
flooded the boiler, no leaks
replaced all the radiator vents with new Hoffman 40s and 1As
found three radiator unions that had slight steam leaks(tightened them and they stopped leaking)
removed 1 new Big Mouth main vent that was leaking steam(need to order a replacement)
and skimmed the boiler for a couple of hours, since the water was dirty/bouncing

Everything appears to be working good, except I have a couple of very small leaks at the threads of a King valve and a flange on my near boiler piping. These are very small and only appear once the boiler has been on for a couple days. I also have a very slight steam leak at the stem of one radiator.

But I still lost 6 gallons in the last week, granted it has been very cold and the system ran alot, but this still seems excessive.

Fred

That is an unusual amount of water. Given the boiler is new, you have to have a leak somewhere in a wet return or elsewhere. Do any of the pipes rise into an unused attic space that may have a vent on it that is stuck open?