How much water is a hissing radiator losing?

david_and_heather

EDIT: Meant to post this in "Strictly steam." Can't figure out how to move it. My apologies.

The first year in my house, the water meter on my boiler ticked up a couple gallons for the whole season. The second year, it used about 20 gallons in the season. Last year, it was using one gallon a week. Each year, at the annual tune-up, I'd mention it to the plumber, who'd shrug. It's a one-pipe system and the boiler is 10 years old.

This year, it's going a lot faster, and I'm worried. I set the thermostat to full blast. In the first 20 minutes, it added two more gallons, and then it didn't add anymore by the time it stopped firing, which took another 45 minutes or so. A half hour after the cycle had ended, the water level was steadily rising without the water meter registering any added, so I don't think the system is blocked.

A few radiators were hissing pretty loudly by about 15 minutes into the test, but all but one of them stopped after another 10-15 minutes. The one that kept hissing did not make any visible steam, and the room it was in did not feel noticeably more humid.

There does seem to be a slight drip out of the 3' hose that my plumber left on the drain valve so it would be easier for me to clean, but we're talking maybe a few drops an hour--nothing like gallons.

It seems far-fetched, but is it possible that these hissing radiators (the transient ones and the one that keeps hissing) are the culprit? Could they lose that much water in such a short time?

Fred

Those radiators (vents I assume) shouldn't be hissing. Do you have good Main vents on each Main? If not, those small radiator vents have to remove the air from the entire system and they hiss in the process.
What pressure is the Pressuretrol set at? It should be set at .5 PSI Cut-in (scale on front) and the white wheel inside the Pressuretrol should be set at "1" facing out. Make sure the Pigtail (looped pipe the Pressuretrol is mounted on) is not clogged. Take it off and clean it otherwise the Pressuretrol can't see the system pressure to control it. You really need a 0-3 PSI or 0-5 PSI gauge on the same pigtail as the Pressuretrol to see what is happening. The standard 0 _30 PSI gauge is useless, except for meeting local code requirements.
If the water level increases after the boiler has shut down, you aren't losing water, it is out in the system somewhere. It could be a slow wet return or it could be high operating pressure where condensate can't return to the boiler until it has shut down.
Is there a lot of Bounce in the water, in the sight glass (more than 3/4" to 1")? It is also possible there are oils on the surface of the boiler water making it difficult for steam bubbles to burst through the surface of the water which will then push some water out into the wet returns until the boiler shuts down. If that's the case, the boiler needs to be skimmed.

EdTheHeaterMan

Can you see all the piping? I had a case where I replaced a steam boiler that had dry returns in a crawlspace partially buried under the sandy crawlspace floor. The returns did not drop below the water line until they got back to the basement. After the second month of operation the water meter on the feeder maxed out at 999 gallons and they had no heat.

I thought 999 gallons was a bit much for 2 months so I investigated the piping and discovered the partially buried pipe was 1/2 gone... the bottom half!

Replaced the pipe and now the boiler uses about 10 to 15 gallons a year. Depends on how ofter the LWCO is flushed.

Big Ed_4

Repairing the leaks that you can see would be your first step , check the chimney for escaping steam for possible leaks in the boiler ... Buried return pipes tend to rot out after 60 years ... Start with the simple

Erin Holohan Haskell

david_and_heather said:

EDIT: Meant to post this in "Strictly steam." Can't figure out how to move it. My apologies.

I've moved it to Strictly Steam.

david_and_heather

Thanks, everyone. The two main vents are new. I had the ceiling off in the basement recently, so I saw a lot of piping I hadn't seen before (asbestos everywhere, had to be remediated and reinsulated).

The pipes I can/was able to see seem fine, and no wet patches at the floors, walls, or ceilings. Doesn't mean that there isn't a piping leak somewhere. I am not aware of any buried piping, but I've never had the basement floor off. No visible steam coming from chimney.

The condensate pump (is that what it's called?) on the return side does seem to either run for a very long time (10+ minutes) and very rarely, and it doesn't sound really sound like it's pumping anything, but what do I know. It did not run at any time before, during, or after the experiment I described, but I heard it running today.

How much water loss per week is enough to warrant calling in a plumber at peak season? This has been the first cold week in my region, so I'd love to wait a bit.

JUGHNE

Pictures showing all piping at boiler....floor to ceiling.
Include the pump and all of it's pipe connection.
Thanks.

neilc

Can you, have you, followed all your returns, either from the boiler, out to where they meet the mains or rad drops?
or from the ends of mains, back to the boiler?
and do any of them go underground, or to hidden areas?
Are there any pipes running down into the slab?

where you have hissing vents, mains or rad vents,
while firing up,
try holding a small mirror, or shiny salad spoon there and see what you see for condensation,

the boiler, while shut down and cooled down a bit(hour or two),
raise the water level, up above the top of the boiler, and let it sit a bit, an hour or two,
then check the floor and burner area for wet,

drain it back down to normal water level before firing back up.

david_and_heather

I love this forum, seriously. You guys are so awesome.

@JUGHNE, photos are in the Dropbox folder below:

https://www.dropbox.com/sh/h369tm67471ie5w/AADe31TZlhKddR_bH0TrvK1va?dl=0

I also made a video, as it seemed like it would be easier to capture the entirety of it that way than with photos. You can see it below. Sorry for the 20 seconds in the middle where I'm hunting down the pull chain for the light under the main vent.

https://www.dropbox.com/s/paz674gilp6506s/20191110_185024.mp4?dl=0

If it wasn't clear from the narrative: I saw 100% of the piping that goes to the two mains and it is all intact. One main was recently replaced, and both get plenty hot.

@neilc Any risk I could break something by doing what you describe? Do I fill it up just by manually running the fill valve, and drain it from the same faucet on the condensate side that I use to remove sediment weekly (where I have that hose I mentioned)?

JUGHNE

What you refer to as a condensate pump is actually a hot water circulator pump. It is pumping the hot water out of the bottom of the boiler thru, most likely, the indirect water heater tank sitting next to it, and returning it to the boiler bottom. The boiler fires as needed to give you your domestic hot water.
OR, it is pumping water to some form of hot water heater unit such as baseboard etc. My guess is the HW tank.

This is often a cause of too much water in the boiler....that is overfilling the boiler. The indirect water heater tank has a coil inside that the boiler water flows thru to heat up the city water inside. If the coil develops a leak the 60 or so PSI of city pressure will enter and come back and over fill the 2 PSI boiler system.
This is not your problem.

You need to do the overfill boiler test as Nelic recommended.
Just do it when the boiler is nearly cold.
Fill until you feel the pipes above get cold from the water fill.
Do not go beyond that. Wait an hour for water to appear on the floor. If dry then some other problem.
Drain back down to water level and be sure to fire up to steam to drive out any oxygen that came in with the fresh water.

JUGHNE

You mentioned you have seen all the steam supply pipes and know there are no leaks.
How about any return pipe that might come out of the floor or walls that you can not see all of the piping??
Those are the most suspect leakers if there.

david_and_heather

Hi @JUGHNE, it is absolutely possible that there is a leak inside one of the walls. We haven't seen any wet spots in the house, but it doesn't mean it's not happening. I'd be surprised if there were a leak in a floor, as we'd notice it in the ceiling of the level below.

Now, three perspective-getting questions:

(1) If I do the test that you and @neilc recommend and do not find anything, is this level of water loss (1-2 gallons a day) something that can lead to a sudden loss of heat and/or other catastrophic malfunction?

(2) If not, will it appreciably accelerate the deterioration of our boiler? The boiler was installed in '07, and I've been hoping it would last at least 20 years.

(3) If there is a leak in a wall somewhere, is there some way I (or my plumber) can find it other than either ripping the house apart or discovering one day that a wall or floor is wet?

ethicalpaul

1. no
2. yes
3. Well you can do a static leak test. You already did the overfill the boiler test to see if the boiler has a hole, right? So if you have the boiler off for a day and the water level in the boiler doesn't drop (you wouldn't be able to tell then until the next time you steamed the boiler since it's the wet return that would be low and that would be hidden until the condensate started flowing) then you know the leak is not a steam leak, and it must be in a wet return. Maybe you know this already...

JUGHNE

Do you have a full basement or partial with craw space?

Your hidden pipes that are potential leakers are most likely return lines.
Every steam carrying pipe must have a way for the condensate water to return.
Some returns in the same pipe that the steam traveled, this is called counter flow piping. Each radiator will probably have the pipe sloped so that the water can drain back to the main pipe that it is connected to.
Some of the main pipes may also be counter flow design....that is steam in the upper part of the pipe and a small water stream flowing back on the bottom of the pipe. These pipes will slope to drain back to the boiler. This water may or not run back into the boiler. The correct way is to drain/drip that water out of the pipe down to the return of the boiler.

Your main suspect for leaking would on a parallel flow steam main pipe. The high point of this main would be at the boiler.
The steam and water flow in the same direction.
At the end of that main there is a return pipe coming back to the boiler. It may be above the water level of the boiler and you could track it physically back to the boiler.
But, if it dives down into the ground and pops up thru the floor or inside wall of the basement, that is the one to look at.
Water could be leaking into the dirt under the floor.

Do you see any pipe that you cannot account for the location of the other end ?

david_and_heather

I wanted to provide the end of this story, as it was a zinger. I did the overfill test--took the front cover off, shut the system down, put cardboard all under the boiler, and added a good 30 gallons of water. Not a drop. (MAN does it take a long time to drain 30 gallons from a boiler using a bucket...)

When I told my plumber all this, he said he wanted to look at it right away because he "wanted answers sooner instead of later." He spent four hours crawling all around the house, rubbing his forehead, muttering.

Finally, the only thing left to question was whether all that water really had been fed into the boiler. His idea was to disconnect the feeder, but if it had been leaking, that would have meant getting up at several times a night to refill the boiler.

So I suggested we shut off the valve to the boiler, open the return cleanout, and measure how much water actually gets fed when the feeder registers 1 gallon.

The answer: about 2 ounces.

The boiler was calling for water. It would barely get any, but since it was shut down, the steam was cooling off and returning as water, so it would fill back up just enough to reach the bottom of the low water probe. As soon as it fired back up, the water level would drop again, so it would shut down again and again call for water. Rinse and repeat. Every time, it registered 1-2 gallons added.

Solution: replace the automatic feeder. Boiler was fine.

ethicalpaul

It makes sense!