Losing Water

[Nofossil]

I appear to have a small leak somewhere, as I lose pressure over a day or two. (My boiler, that is - not me personally). I pressure tested everything when I put the system together, and there are no visible leaks anywhere. I have had a little seepage around shutoff valve stems - never enough to be wet, but enough to have some deposits of various colors. I've tightened all the packing nuts, but it seems like there must be a good deal more leakage than that could account for in any case. More details:

If I pressurize to 20 lbs, I'll be down to 15 the next day and 10 in another couple of days (all pressures with boiler near room temp). It won't drop much below that. I don't know the flow rate through my refill plumbing, but it seems like 10psi to 20psi takes several quarts at least.

Outside the boiler room, there are NO visible leaks or seepages. The basement and main floor plumbing is almost all exposed, but there's a fair amount of plumbing in the walls and ceiling for the top floor zone. Even so, I'd expect a quart of leakage would show on the sheetrock somewhere.

Anyone have any ideas or personal experience with this kind of situation? Any suggestions for troubleshooting steps?

I'm considering pressurizing to 20psi and shutting off a couple of zones for a couple of days to see if that can isolate the problem.

 

[taxidermist]

Can you close off ball valves on the boiler and pressure test just the boiler thru the drain on the back of it? If its leaking into the fire box you will never see the leak because it will turn to steam and go up the chimney.

Rob

 

[Donl]

I appear to have a small leak somewhere, as I lose pressure over a day or two. (My boiler, that is - not me personally).

I had a similar problem a few years ago. Turned out to be a faulty shreader (sp) valve on the expansion tank and a loose fitting there. I found the problem area using the soapy water method.

Don

 

[Fred61]

I had this problem with the Wood Gun. It took me a while to discover that the burn chamber walls had become porous and water was seeping into the box over a large area which made it nearly impossible to detect. It was going up the stack as steam. I hope your problem is something different.

 

[Bad Wolf]

If I remember you have unpressureized storage, could it be leaking into there? A couple of quarts might not be noticed untill it overflows. I don't know about yours but I actually have to add some water to my storage tank every now and then to make up for evaporation. There are a couple of spots where I can see vapor sometimes.

 

[kopeck]

I had the same problem last year and I'm 99% sure it was the packing nuts on a couple of ball valves leaking.

I haven't had an issues this year, I snugged them all up. What a pain it was t find them though.

K

 

[mmudd]

I have a friend who has had numerous leaks due to pinholes deveoping in the copper coils submerged in his open storage, EPDM lined tank. He had no issues until the systme had been in place more than 10 years I think. His storagetank would eventually leak from an overflow.

 

[Nofossil]

Thanks for the ideas. My storage needed about ten gallons added to it to maintain proper level - that's after five years. Don't think I'm losing it in storage.

I could isolate the boiler from the zones and pressurize it cold and see what happens. It really seems like a couple of quarts should be obvious.

 

[salecker]

Did you do anything to open the system this year?
Reason i ask is i upped the preasure in my expansion tank this year before the first burn,i checked the preasure and thought it was low,anyhow it blew out a bunch of water when it got up to temp.I let the preasure back down and replaced the water,or so i thought.I had to add some more water every couple of weeks,which continued for to long i thought.So my first thought was a leak then i began to worry,no signs anywhere of leaks.....
Finally it's been over a month since i'v added so i think the air is finally gone.
Thomas

 

[Nofossil]

Did you do anything to open the system this year?

I just replumbed half the boiler room and the whole main floor zone. I've had this phantom leak for years, and I hoped it would go away with all the changes. It didn't. The pressure doesn't seem to go to zero, but it definitely won't stay at 20.

 

[Nofossil]

Found it! Bad sweat joint of the top floor zone (at the highest point in the system). Apparently only leaked when hot, and not enough to drip. Of course, it would never leak below the head pressure of two stories height (about 8 or 10 psi).

 

[goosegunner]

That is good news, Glad you found it!

gg

 

[DaveBP]

Useful lesson, that.

A leak that stops at a given pressure greater than ambient is telling you the elevation above the gage to start looking. Never would have occurred to me.

 

[BoilerMan]

Good to hear you found it NoFo! I was talking to a gas/heating guy a few weeks ago as he was connecting the gas (LP) service to a boiler I was installing. I had the system air pressureized the first day he was there. He was asking me how much pressure I used and I told him 25 psi of air, and hold it for at least 24 hours with no drop (temperatures considered). He said they always do the same, but had an un-soldered joint hold the air for several days, and water as well, it was a few days later and 180 degree water that finally washed the flux out of the joint and a leak appeared. Who would-a-thunk-it????

TS

 

[Nofossil]

Live and learn. I'm really glad to have this one behind me. Took a day to flush out the last of the air bubbles. Pressure is stable and no air noises at all.

 

[kopeck]

Good to hear you found it NoFo! I was talking to a gas/heating guy a few weeks ago as he was connecting the gas (LP) service to a boiler I was installing. I had the system air pressureized the first day he was there. He was asking me how much pressure I used and I told him 25 psi of air, and hold it for at least 24 hours with no drop (temperatures considered). He said they always do the same, but had an un-soldered joint hold the air for several days, and water as well, it was a few days later and 180 degree water that finally washed the flux out of the joint and a leak appeared. Who would-a-thunk-it????

TS

Sometimes I think it might be a neat profession but chasing leaks, the small ones anyway would drive be crazy.

K

 

[heaterman]

Useful lesson, that.

A leak that stops at a given pressure greater than ambient is telling you the elevation above the gage to start looking. Never would have occurred to me.

Exactly. 1PSI =2.31 feet of head.

 

[Hydronics]

Exactly. 1PSI =2.31 feet of head.

Or the inverse: each foot of head = 0.433 psi