How much water can go out the shutoff valves

HarryL

I have a 15 year old steam boiler for our small house. Last year I was losing water and had to refill about once a week. I discovered that the emergency pressure valve had a leak. I replaced that and also put two gorton #2s on my mains. Water loss was fixed, though I was getting a little hammering I hadn't heard before. This was towards the end of the season. Unfortunately once summer came I didn't pay much attention to the system.

This year we turned on the furnace now we are losing a lot of water, even more water that last year. For example, I filled up to the normal mark on the glass and in 24 - 48 hours it is down to the cutoff. The emergency pressure valve is working correctly. When I close all the valves the system comes up to pressure then shuts off. I've tried to check the chimney but I don't really see steam coming out. I'll check again, but I have noticed that six of nine radiator shutoff valves are leaking varying degrees of steam.

Can this much water be lost through the shutoffs alone? I don't think it is backing up the wet return into the dry, but I suppose that might be possible. The wet return doesn't have a good way to clean it out so I suppose it could be clogged after 15 years

I've got some graphite packing string so will try to fix up the shut offs. Anything else I should look at?

Thanks,
Harry

Jamie Hall

An amazing amount of water can escape from leaking valves and vents. It's worth repacking them.

A clogged wet return would slow the water coming back to the boiler, but unless it's hopelessly plugged -- unlikely -- the water will come back.

Your comment about the emergency pressure valve bothers me, however. That is a last ditch everything else has gone wrong safety device, and should never, ever leak. If it pops and releases water or steam, the cause of the overpressure must be found and fixed before the boiler is put back in service -- and I advocate replacing the valve at that time.

Which leads me to... what pressure is your system set to cutout at? Check the pressuretrol or other pressure limiting switch. It should be set to stop the burner -- cutout -- at no more than 1.8 psi, and then allow the burner to restart -- cutin -- at about .8 psi. Too high a pressure can make even small leaks much worse, not to mention burning extra fuel -- and destroying vents and traps in the process.

Fred

If the boiler builds pressure, it likely isn't steam going up the chimney. 6 of 9 valves leaking steam is a source for lost water. How much is a tough question to answer. Repairing those will tell that story. Check the piping and/or radiator where you hear hammering. It sounds like maybe a pipe or radiator is out of pitch too. I'm doubtful the wet return is clogged. If it were, I'd expect the water level to be low after each heating cycle and, at some point, when the boiler has been idle for a few hours for it to be over-filled, between the added water and the slow return water.

HarryL

Jamie Hall said:

Your comment about the emergency pressure valve bothers me, however. That is a last ditch everything else has gone wrong safety device, and should never, ever leak. If it pops and releases water or steam, the cause of the overpressure must be found and fixed before the boiler is put back in service -- and I advocate replacing the valve at that time.
.

I couldn't see anything coming out, but I noticed the basement floor was discolored under the copper pipe. I put clear plastic bag around the bottom of the pipe. A day later water had collected in the bag.

I replaced the valve. No more water collecting.

Jamie Hall said:

Which leads me to... what pressure is your system set to cutout at? Check the pressuretrol or other pressure limiting switch. It should be set to stop the burner -- cutout -- at no more than 1.8 psi, and then allow the burner to restart -- cutin -- at about .8 psi. Too high a pressure can make even small leaks much worse, not to mention burning extra fuel -- and destroying vents and traps in the process.

1.5 / .5

HarryL

We just filled the boiler up to the headers and water started running out. The boiler guy is here and despite his youth is very much into doing steam the right way and a big follower of @Dan Holohan and the dead men.