Steam Boiler flooding

Mark_H

Good morning,

I have a Slant Fin steam boiler that is apx 16 y/o. This season Ive noticed that the boiler is calling for an unusual amount of fresh/new water. Its gotten to the point where I can hear water sloshing about when its running. So bad that I have turned of the water supply to the water feeder. It seems that the sensor probe is impatient and wants to top off the boiler before my condensate has had time to return. I don't get any water hammer though, just sloshing water as if Im below decks of a boat. After a few days, the system finally shuts down as there is not enough condensate that has returned and there is no automatic water feed, so the system shuts down. Thats when I open the water line and let the boiler fill once, then cut the water supply. It will then heat for a few days before I repeat this process. The house is heating fine.

My immediate fear is that while the water source has been shut off, when my electric water feed calls for water, and gets none, I'll burn up the feeder?

The 2d issue is how to remedy the problem.

~Mark

Mark_H

As a continuing thought, perhaps my steam valves at the boiler returns have failed? If the vacuum doesn't break, they would be holding back the condensate, correct?

nicholas bonham-carter

If you observe the full cycle, with the auto feed valved off, at what point do you see the water level drop enough to turn off the boiler?
My guess is a plugged wet return, preventing a quick return of condensate. Is there any point on the wet return for a valve to enable a good flush out of the piping?—NBC

KC_Jones

When was the last time you flushed out the wet return pipes?

Fred

Pictures of the wet returns (pipes below the boiler water line) would help.
- Is there one or more long wet returns, near the floor or just a short one near the boiler?
- Is this a one pipe or two pipe system?
- How many times have you had to refill the boiler so far this season?
- Where do you hear the sloshing? In the pipes or in the radiators?
At some point, if you continue this process, you will have water blowing out of all of your radiator and main vents. Not a good thing. There is always the possibility that the boiler block has a hole in it, above the water line and the water is steaming out of the chimney but the sloshing causes me to believe it may be a blocked wet return. Do you see white clouds coming out of the chimney when the boiler is running?

Mark_H

Chances are they have never been flushed? There is no way to get to them. I do blow down every month, or rather as I remember to.

Mark_H

Fred
I'll post pics when I have some time. My system is a two pipe 1st floor, one 2d. As far as the boiler feed Ive lost count, but my guess is well over a dozen. Sloshing is in the steam/feed pipes, not the rads. I know not to let everything over fill to the flooding point. That happened once years ago and it aint pretty.
I will check the chimney for steam escaping and get back to you.

***Anyone have ideas regarding letting the McDonaldMiller water feed run w/o having water feed through it?***

Mark_H

NBC-
Boiler runs for about two days before the low water cut off shuts things down and I have to turn on the H2O long enough for it to rise back to the fill line.

I should point out that the house is staying warm and I get NO water hammer.

Mark_H

I should also mention that all the 2 1/2" horizontal feed pipes in the basement were replaced this past summer. The were starting to fail. I did not replace any of the return condensate lines. They all seem good yet.

KC_Jones

If you are filling every couple days that is excessive water usage, very excessive.
You are losing water somewhere. Once a month just to maintain the normal water line maybe, but certainly not due to actual low water.

Are the return pipes buried under the floor?

Also failing steam lines could be an indication of other issues such as wet steam. The steam pipes typically don't corrode unless something is wrong. Did the person who replaced them mention this?

Mark_H

KC-
I agree Im losing H2O, but where? Has to be in the lines somewhere. Pipes are above ground and I'll try to post up a pic ASAP.

The replaced pipes are original to the house that was built in '23 so they were pushing 100 years old.

KC_Jones

Mark_H said:

The replaced pipes are original to the house that was built in '23 so they were pushing 100 years old.

That's normal and not necessarily a problem. My house was built decades before that and still no issues with the piping. Like I said corrosion (to replacement) isn't typical on steam supply pipes. Return pipes are a completely different story.

The loss is somewhere, have you checked the chimney for steam outside? Have you checked and repacked all the steam valves? Many times it isn't one smoking gun, but a bunch of little things that add up to massive water loss.

If the returns are plugged solid it could be the water is just out in the system and you aren't losing that much. I would be suspect of the return lines from your description. If you have no service valves to drain or flush the return lines you may need to call in a pro to open them up. At that point you could have some service valves added to help in the future.

Where are you located? We may know someone competent in your area that can take a look for you.

Fred

If you hear sloshing in pipes, those pipes either have a sag in them or are pitched the wrong way or your pressure is way too high. Like I said earlier, if you are adding water every couple days, and all your pipes are visible, steam must be going up the chimney, or vents aren't closing. Is your house or any areas of your house unusually humid?

Mark_H

Im in N W Ohio. None of the rooms feels humid or steamy. I think I may start by buying new air valves for the returns

nicholas bonham-carter

Check for a leak in the boiler first by switching off the boiler, and then overfilling, while not hot, until the header feels cool from the water rising up in it, and then let it sit for an hour or two.
any leaks will show up in the firebox, or on the floor.
Any trapped water in the returns will eventually come back, so there must be a leak somewhere.--NBC

Mark_H

I'll have to do that on a warmer day, we're below freezing for a few days. I like the idea of this though. I see no steam up from the chimney BUT, I have a cap over it and that may cause condensing on the underside?

Mark_H

OK so I had a thought. I un-screwed the Hoffman air vent on my wet return that gets most of the return condensate and water came gushing out. My guess is the STEAM TRAP that is connected to it is the trouble maker, not allowing the H2O back to the boiler. This part of the house is where most of the gurgling is coming from...It seems. Im thinking of having the STEAM TRAP removed and seeing if that fixes the problem.

Has anyone ever seen this set up? Why would there need to be a STEAM TRAP on a return?

Kahooli

im confused.... could you zoom out? show what all is connected there schematically even?

EBEBRATT-Ed

part of his system is two pipe and part is one pipe as he said.

@Mark_H , you most likely have some trap(s) that have failed closed.

You can buy the parts to rebuild the traps yourself if your handy. I would rebuild all your traps. Most of them are probably radiator traps. Look on the trap cover for manufacturer and model etc

Start with the traps that are on the piping where you here sloshing, but you should rebuild all the traps. A partial replacement may cause other traps to fail

Fred

The purpose of a trap on a return is to prevent steam from getting into the main and hammering. That trap in your picture??? I don't know why that is there. It looks like that is just a vent off of the return but the vent looks way too close to the floor. That Hoffman 75 vent should be up near the ceiling.

Mark_H

Fred Its just the pic. Its about 6' off the floor.

I removed the plug under the vent in the pic and got NO WATER! I was very surprised. Now what?
I have a ball float steam trap that I think may be plugged up. Its been in about 15 years. That too may be causing my blockage