Bad LWCO?

Jason

I'm a new HO with a one pipe steam system in a 3000sf 3 family house. The system has been fine (except for the fuel bills) for the 3 months I've owned the house and all floors heat well. But two days ago after I shut off 3 of 4 3rd floor radiators due to vacancy, my boiler started flooding!? I shut off the system and waited an hour or so, drained the water to the appropriate level and enabled the system. Next day the boiler is flooded again. I drained the boiler and shut the auto water feeder valve so it can't flood the boiler.

I observe the following during system operation. Boiler fires and runs normally. Water line moves +/- 1 inch in the gauge glass around the water line mark on the boiler. It never drops near the bottom of the glass. After boiler stops firing, the auto feeder tries to feed the boiler even though the water level is perfect. The auto feeder cycles a few times and eventually the boiler comes back on and appears to run normally. But the auto feeder tries to flood it after it stops again.

The near boiler piping looks very good. Just like it says in Lost Art and WM installation manual. It doesn't appear to me to drive water into the returns. The Hartford loop is piped just right at 2in. below the water line. Other than the auto feeder trying to flood the boiler, the system is still working fine and the house is warm. To my novice eyes, it seems like something in the LWCO is getting confused and is telling the auto feeder to fill the boiler even though the water level is perfectly fine.

Service company is coming this afternoon but I'd like to have any opinions from the wall regarding what might be the root cause of the problem. After speaking to them on the phone and describing the above, they told me that it would require 3-4 hours to replace the auto feeder and cost $400-500. It doesn't even sound like there's anything wrong with the auto feeder to me. The LWCO seems to be telling the auto feeder to run. But I don't know the specifics about the control of the auto feeder.

Any advice appreciated. I really enjoy all the topics about steam on the wall.

Jason

DanHolohan

What's the

model number of the boiler?

hot_rod

low water

Jason,
Something feels funny about this...Is the top gauge glass cock open and not plugged up?

If it is clear, is the top pipe to the LWCO open and working?

It might be that the glass is not showing an accurate indication of what's happening in the boiler, but the LWCO is actually doing it's job. When you removed some radiation in the house, the boiler might act overfired, which would give those symptoms, all except the glass not dropping it's water line. Try shutting the bottom glass cock and blowing out the glass from the top cock. It is a quick test that costs nothing.

I'm not sure this is the problem, but I had to mention it.

Noel

Dale

Noels comment

Is good, do check the gauge glass for open valves, open the boiler drain and watch the gauge glasss water lever fall. Closing the 3rd floor rads isn't a good idea, they can leak in and hold water which can cause the feeder to feed and then slowly drain back flooding the boiler. If the feeder is controlled by the LWCO bottom contacts fill to 1/2 a gauge glass, open the boiler drain and see where the feeder starts and stops. Feeders can and often do leak through so do a broken union test to check for a smalll feeder leak.

Steamhead

And is the LWCO

a float-type (as McDonnell & Miller #67, attached to the sight glass on the boiler) or a probe-type?

If it's a float type, the short 1/2-inch pipes between the boiler and the LWCO tees may be partially obstructed. This would cause a delayed reaction to the actual level in the boiler, which would keep the feeder on longer than needed. Try removing the sight glass fittings and sticking a long screwdriver or wire thru the tees as far as the boiler. If you get a lot of dirt, you've located the problem- set the boiler up again and try it. If the pipes between the boiler and the LWCO tees are of steel, replace them with brass ones.

If you have a probe-type LWCO, the probe that sticks into the boiler probably needs cleaning.

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Jason

bad switch

Thanks for all the suggestions. The service guy came today and checked things out. He replaced a switch in the LWCO. I guess there are two sets of contacts in there. One that operates the water feeder prior to the one that cuts out the boiler on low water. The first one that controls the feeder was always on. He replaced it and everthing's fine. I guess it was a coincidence that the boiler flooding started around the same time I turned off the heat on the 3rd floor. The service guy recommended that I not shut the heat off just as Dale said so I intend to turn them back on this evening.

Some details. The boiler is a WM SGO6. I can't remember the mfg of the LWCO but it's the standard one that comes as part of the boiler package. The bad contacts were the lower two sets of terminals. This whole thing is simple enough to troubleshoot if you know what to expect from the different pieces. I just didn't want to take things apart without knowing what I was getting into. Turns out it's relatively simple once somebody that knows what they're doing explains it....

It was nice to learn that my fuel company's service staff knows all about Dan's books and seminars. Gives me some confidence that there are good steam people close by. Jim from White Fuel could pretty much recite from the Lost Art.

Thanks again,
Jason