Boiler Overfilling

Old 12-30-06, 05:07 AM
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Boiler Overfilling

Hi all,

I found this forum while searching for some answers to my steam boiler.

I first found this thread:

It is somewhat like my problem.

A little background:

Older home, three floors plus basement. Steam boiler with LWCO & Autofeed.

Recently, I've noticed that there would be water dripping out of the autofeed valve, which was due to overfilling. I would drain the system down to half the sight tube, and everything would be fine. This morning when I got up I heard a slight dripping or pi$$ing noise coming from the dining room. I found that there was water being forced out of the radiator steam valve, and when I removed the valve about a quart of water poured out of the valve opening.

Went to the basement, and there was water dripping out of many places along the system, the boiler was shut down and the pressure gauge was up to 5-6. (It's usually around 1.5-2)

I shut down the ball valve ahead of the feeder, started draining the boiler off, and drained out a good 10 or so gallons or more before the sight tube was in line.

What else do you folks think?

Strainer in the water feed needs cleaning?
LWCO needs attention?

The water feeder is off for now, and the boiler seems to be firing just fine. The water level is bouncing around in the sight tube while the boiler's firing.

I don't have any banging or waterhammering, and really not even any out of the ordinary sounds. I hear air being pushed out of the radiator and the rad valves snap shut, but no teapot whistling even. I think that's a good thing.

Thanks for the input.

Old 12-30-06, 05:41 AM
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What type of LWCO do you have? Float or probe? Does the water feeder only make noise when the boiler is running, or is it all the time? If you have the float type of LWCO, Flush it while the burner is running to verify that it is working properly. The burner should shut off while flushing, then come back on after. When was the boiler installed? Service history? How often do you have to fill it when the AWF (automatic water feeder) is off? The leaks you found when the boiler was over filled, are they easy enough to fix? Leaks are not good to have. Also, when air vents get flooded, they will often not work right after that. Check to see if they are working properly.

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