STEAM BOILER OVERFILLING

cliffpotter

I have a single pipe steam boiler. When my boiler runs constantly I have no problems. My problems occur when the boiler goes off and on in the warmer weather. The Warm Weather Sensor shuts the boiler down. And of course when it cools off the boiler comes on. I check the water level twice a day. The water level constantly is too high. The boiler has shut down on occasion from the High Level. If I did not lower the water level every day the boiler would shut down every day. Any help would be appreciated.

Jamie Hall

You need to figure out where the extra water is coming from before you can fix it. Possible problems include domestic hot water coils which can leak, leaking makeup water bypass valves, poorly adjusted or malfunctioning automatic water feeders...

For reference, a steam boiler should not use more than a few quarts a week, if that (systems in really good shape may use no water at all in a whole season).

A high level shutoff is a little unusual on a residential steam boiler. Can you describe it further?

cliffpotter

If the boiler gets too full of water it shuts down. Would this not be a high level switch?

JUGHNE

I posed a similar question a few years ago, several answers came back that the water pressure would open the pressure switch.

How do you heat your hot water for the sinks etc?
As Jamie asked a coil inserted into the boiler could be leaking.
Or your water feeder is over filling. You can shut off the auto water feeder as long as your low water cut off safety device is working.

Pictures would show a lot....floor to ceiling showing all the piping.

Jamie Hall

cliffpotter said:

If the boiler gets too full of water it shuts down. Would this not be a high level switch?

As @JUGHNE says, if the pressure switch is mounted on the front of the boiler block or on the sight glass, it doesn't take a whole lot of extra water to open it and turn the boiler off. It's not really a high level switch, although it does act that way -- it's intended to shut off the boiler if the steam pressure gets too high.

EBEBRATT-Ed

@cliffpotter What @Jamie Hall said,

you need to figure out where the extra water is coming from before you can fix it. Possible problems include domestic hot water coils which can leak, leaking makeup water bypass valves, poorly adjusted or malfunctioning automatic water feeders...

Fred

I would also like to understand what he/she is referring to with the "warm weather sensor". Other than a thermostat, in the living space, I'm not sure what that might be?

cliffpotter

This is not a residential boiler. This is a commercial boiler in a 12 suite 3 floor apartment block

JUGHNE

All of the suggestions above still apply.
You may have slow condensate water return.

Do you have a condensate pump.....or a feeder pump?
Or you might have gravity return with no pump.

Pictures would still be good.

cliffpotter

I will get pictures. There is an autofeed and there is a condensate return pump. I do not think the autofeed is the problem. Is there any way water can backfeed from the outgoing steam supply lines. I appreciate all the help. Thank you.

Fred

cliffpotter said:

I will get pictures. There is an autofeed and there is a condensate return pump. I do not think the autofeed is the problem. Is there any way water can backfeed from the outgoing steam supply lines. I appreciate all the help. Thank you.

What triggers the pump? a float? if so is it properly set? Does the autofeed feed a tank or directly into a wet return/boiler?

JUGHNE

So your pump turns itself on when it fills with return cond water?

Or does the boiler level control start the (feeder) pump?

Jamie Hall

This ^^^ is absolutely critical for advice... also what, exactly, tells the autofeeder to feed?

DanHolohan

@cliffpotter are there zone valves at the boiler?

dopey27177

Most likely the auto valve is worn and leaks.
Dan asked a question that's not answered.
My question is, is this a new problem or has this been going on for a long time?
I ask this question because there is a thing called condensate time lag. this means something is causing the condensate to return to the boiler or pump set to slow.

So you need to provide some pictures of the pump installation and wet return piping to the pump set and boiler.

Jake

roncook

Possibly partial blocked returns causing condensate to back up in the system. Then the feed pump fills boiler, and finally the condensate makes it way back to the boiler overfilling it.

Joe_Dunham

You may have a condensate pump OR you may have a boiler feed pump. They both feed the boiler but a condensate pump discharges when it is full regardless of whether or not the boiler needs the water. A boiler feed only feeds when the boiler calls for water (the pump control is mounted to the boiler (BWLC). This could be the scenario; the boilers firing for steam, and the water level drops, the auto feeder fills the boiler, then the condensate eventually comes back to the pump which come on whether or not the boiler needs water and you wind up with a flooded boiler. Very common, especially when old large volume boilers are replaced with low volume boiler. The feed tank acts as a reservoir and allows water level to fluctuate in the tank rather than in the boiler. Then of course the auto feeder can be passing a little water or a tankless coil is weeping into the boiler. But if the later is the case it would flood 360 days a year

dopey27177

Still would like to see a picture of your condensate pump>

Jake