Diagnosing faulty feeder shutoff

Tad Wysor

...before dismantling the low-water cut-off unit? Thanks to the folks that responded .. I understand the system better, and I'll probably try cleaning out the low water cutoff. But sounds like nobody has an idea yet for how to check for faulty operation over time when I'm not in the boiler room? See, even if dismantle the cutoff unit and I think I might have freed up the switching mechanism, the only way I know it's fixed (or whether it really was that component and not the feeder unit)is if I turn the feed water back on and see if it floods the system (and my first floor radiators!) in a week or two!

I'm still hoping somebody out there can sugggest some ingenious way of recording the signals over time to catch the intermittent fault, and then see if the fault goes away after the guilty component is fixed or replaced! Then I could sleep -- with the feeder water supply turned ON!

Tad Wysor

My one-pipe home steam system has me and my contractor stumped. After several years of problem-free operation, it's started intermittently flooding, right up to the first-floor radiators. After a couple of visits and going thru the checklist at this site (thank for that!), seems it's either 1) my low-water cutoff sometimes does not send a signal that says "I'm satisfied, you can stop feeding water now" after it calls for a feed, or 2) or my feeder control is not always responding to the signal to stop feeding. We haven't been able to make this happen while we are watching -- everything works fine while we're there. Meantime, I've shut off the feeder water supply and am manually adding H2O every few days.

My contractor's gone back to the shop to scratch heads with his colleagues there, and I'm scratching heads with anyone who has an idea on this. He's not eager to change either the low-water cutoff (McDonnell No. 67) or the feeder control (Sensit Safegard by Hydrolevel Co., VXT-120) without knowing which is malfunctioning.

Any ideas? For example, is there any simple technology we could attach to either component for period of time to monitor for a failure for the cutoff to send an "off" singal to the feeder controller, or to monior whether the controller is failing to shut off the feed when it gets the "off" singal?

ed wallace

water feeder test

if its a line voltage feeder which it sounds like get a light bulb pigtail at hardware store wire it into l1 and l2 on feeder drain water and watch the light bulb to see when it goes off if its a 24 volt feeder you will need an led light which can be bought at radio shack and do the same thing

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Tad Wysor

Thanks,but not sure I understand. When I drain water in order to kick on the feeder, I can clearly hear when the feeder opens and then when it shuts off, which it always has done within a few seconds when we've experimented with it. Problem is when I'm NOT there and it fails to shut off and fills the system, which can be days after I checked it out. With your idea, wouldn't I still have to be there to see the light? If I did somehow catch the feeder not shutting off, still not sure how I would tell whether it was the signal to the feeder or the feeder itself?

Tom M.

feeder

A few thoughts: The #67 has two switches in it that operate at different times. When the float bowl is flushed to the point where the burner is cut out, you should hear two clicks as the float comes back up. The second click is the feeder switch. If the float has some water in it or a lot of dirt on top or in the bellows, it may not be coming all the way up under running conditions. When you test it, it comes up quickly and has slightly more momentum than it does when its being filled during normal operation. The float may be dropping slightly and not coming all the way back up. Hope this helps.

John@Reliable

Adding water?

You said that your adding water "every few days" if this is true,first must find where the water is going. Unless this is a BIG boiler adding water every few days is a sign of a leak in boiler or vents. I would find/fix leak then pull apart #67 to check and test float,auto-fill check for clean strainer & pos. valve shut-off. Alot of water thru auto-fill can cause pitting of seat letting small amount of blowby causing system to over-fill and also can cause float to rot out. P.S. This is why I don't like auto-fills on small home systems,they can mask a problem,steam systems are a "hands on" type of system that are great when maintain. Hope this helps John@Reliable

[Deleted User]

Why look for a high tech

answer to a low tech problem? Either the 67 is hanging up, or the feeder is leaking through, or there is a system problem that needs to be addressed. No matter how hard we try to dress up a steam heating system, it is still 18th (yes, the 1700's) century technology.

The 67 is a simple animal. A float, that may or may not, be sticking. And. A #11 switch. Check them out.

The feeder opens to an electrical signal from the 67. Or. As is possible with all water feeders, is it leaking through when it is supposed to be closed? Do a broken union test on the leaving side of the feeder. What? No union. Install one. While you're at it. Clean out the feed water connection at the return.

System problem? Maybe. Is the boiler water priming and surging? Is the wet return full of mud, or other detritis? Are the main line vents operating properly? Is someone turning 1 pipe radiators on and off? Have you recently removed some of that nasty white pipe insulation and not reinsulated? Something to think about when you wake up at 2 AM and can't go back to sleep.

If. Just if, it is the water feeder, make sure the new one has a time delay built in. Good luck.

Jason

wish i had read this thread

before i posted a very similar one called Bad LWCO? my service company came out today nd diagnosed a faulty switch in my LWCO and replaced it in less than an hour and showed me how all that stuff worked. almost had the exact same conversation with him that ron posted here. luckily for me, the feeder switch was 100% bad all the time. your's may be too and there may be a delay installed in the feeder that makes you think the problem isn't present all the time.

i found out that my feeder had not only the built in minute delay but a cheesily added 1-10 minute delay timer for exactly the system reasons ron mentions. i guess my system sometimes can trip the feeder switch (like when i shut off the 3rd floor radiators) for long enough to cause the feeder to add water. then eventually the condensate came back and flooded the boiler. so someone in the past installed this 10 minute delay in it and wrote on the side of the feeder to leave the delay at 10min.

luckily, my system works fine without the auto feeder enabled so that's how i have it set up now.

Tom Minzenberger

I agree with John. You shouldn"t have to be adding water every few days. First and foremost, find out where that water is going! Secondly, is burner cutting out at at the intended setting. All that fresh water means more than a usual amount of sediment/sludge build up in the controls. I've seen that sludge settle in the pigtail for the pressure control,there by isolating the control from the system. The result is the only thing controling the burner is the room thermostat. On a call for heat, system may be building up to much pressure and not allowing the condensate to return to the boiler. The feeder senses a need for water and does its job, ADDS WATER. While you are troubleshooting your problem, check the pigtail. It's quick and easy to do. Just a thought.

Dale

Besides the other posts

I would check your water pressure, feeders do best with lower water pressure, a water boiler pressure reduceing valve ahead of the feeder is a good idea.I think you have a BAD FEEDER the hydrolevels I see will only feed for a short time and then are locked out by a stacked bimetal time delay relay on the old stuff or a electronic circuit. Even if the 67 kept calling for water (bottom 2 screws closed) you wouldn't flood. I would definately pull the float and switch out of the 67 and scrape the sides and back with a large flat screwdriver, I think that may be a portion of your problem and not dropping on low water is MUCH worse than not coming up and flooding, I think the pipe on the hydrolevel is 3/8 and may be feeding so slowly a gummy float in the 67 isn't popping up to open the feeder connection this will get you if the feeder isn't shutting off with constant power applied. You can wire a simple clock or relay to the feeder signal but comparing to water flow would require a differential sensor or a timed water meter.