Water feeder comes on, but doesn't actually feed water to boiler

Eric Scheidler

Hi there!

Last winter I asked this forum for help with a water feeder that was sporadically overfilling my boiler. It was suggested that I clean the LWCO probe, which I wasn't able to get to until today. (I just kept a close eye on the water level through the season and emptied water out of the boiler when it randomly got too high.)

So I cleaned that probe today (McDonnell & Miller Model # PS-802-24). It didn't look too horrible to me, but was pretty thoroughly coated with rust. I cleaned it off with steel wool, and reinstalled it. BTW, I did not know until doing research recently that this probe is to be cleaned every 5 years; I've been here 17 years without touching it.

When I turned the boiler on, the red light on the LWCO came right on, and the boiler snapped off. A minute or so later, the feeder (McDonnell & Miller Model # WF2-U-24) came on and ran for a few minutes. However, the water level sight showed no movement. The low water light remained on.

I tried manually feeding for several minutes. Nothing.

Now, last winter it did seem to me that the feeder was operating much slower than I remembered, so perhaps there's some kind of clog or something. But it was still working at the end of the season.

Here's a 15-second video
I shot so you can hear how it's coming on. Sounds to me like water is flowing, but it clearly isn't.

The family are really keen for me to fire up the boiler for the season. Grateful for any advice on how to proceed troubleshooting and fixing this problem!

— Eric (handy homeowner)

EBEBRATT-Ed

Your going to have to take the feeder out and troubleshoot and see if it is clogged, or a shut off valve is not open (stem broken) etc etc.

For now so you can get the heat on get a garden hose and hook it to a water supply (at the washing machine maybe?) and hook it to the boiler drain and fill the boiler through the boiler drain.

Your going to need a female-female garden hose coupler (or steal a hose off the washing machine)

Make sure the low water cutoff works and make sure to close the boiler drain and water supply valves

STEAM DOCTOR

Obviously make sure appropriate valves are open. You might have a backflow preventer that is clogged

Eric Scheidler

Thanks, guys. I filled the boiler today with a garden hose. Found a female-female coupler for the hose.

If you had to guess, would you think the clog is in the backflow preventer, or the feeder valve? Now sure where to start my troubleshooting. Or perhaps I should ask which is likely to be easier to check (all things being equal, check the easier option first, I reckon?).

Jamie Hall

My first guess would be the valve in the water feeder. It's small, and solenoid powered -- and notorious for sticking either open or closed. It could also just be the filter screen in the feeder is clogged, if there is one.

Eric Scheidler

Thanks for the advice, Br. Jamie. And thanks again for your help last year getting a cold radiator firing red hot last winter!

mattmia2

pictures of how the feeder is piped? Is there a separate manual bypass valve?

Eric Scheidler

Here's some photos of how the feeder is piped. No, I don't believe there's a manual bypass valve, but I'm inexperienced enough to be sure.

mattmia2

that valve under the feeder is off. turn the handle parallel to the pipe to open it. make sure it isn't off because the auto feeder wasn't shutting off, watch the level for a while to make sure it doesn't overfill

Eric Scheidler

In another thread on a similar problem, it was suggested to "clean the strainer," which was described as "the plug on the back that is at an angle." Is that this?

And if so, should I try to remove it and clean it out?

mattmia2

That is a strainer, but it isn't going to feed with the valve between it and the boiler closed.

Eric Scheidler

mattmia2 said:

that valve under the feeder is off. turn the handle parallel to the pipe to open it. make sure it isn't off because the auto feeder wasn't shutting off, watch the level for a while to make sure it doesn't overfill

...

mattmia2 said:

That is a strainer, but it isn't going to feed with the valve between it and the boiler closed.

I should have explained when I posted the pictures that I shut off both valves — the one before the backflow preventer, and the one between the water feeder and the boiler — because I knew I would be working on one or the other of those parts of the system in order to solve this problem.

So to clarify, with both valves open, the water feeder comes on but does not feed the boiler at all, appears to be completely clogged somewhere along the line.

So this being the case, should I remove that plug and see about cleaning out that strainer?

mattmia2

Yes. Depending on how the strainer seals you might need to find a new gasket for it or get creative with some teflon tape. Also, if you put a bucket or cup or something under the opening for the strainer and slowly turn on the valve, water should come out, you can at least show you have flow to there and flush out anything in the strainer chamber.

pedmec

i would start at your backflow. the backflow has a screen on the inlet which will get plugged all the time. just loosen the nut on the down stream side of the valve and then turn the water on. if you get flow you, reassemble, move on downstream.

neilc

I'm curious,
what's the deal with the plywood corner table on the water feed line?
vibration/shock isolation

mattmia2

Looking at it some more, that angled cap might be how the innards of the valve are installed in the fitting. If you remove it, just be very careful you get everything that comes out of it, it probably is spring loaded if it is the valve.

It is a strainer, here are the instructions:
https://s3.amazonaws.com/s3.supplyhouse.com/manuals/1351002065510/84641_PROD_FILE.pdf

Eric Scheidler

neilc said:

I'm curious,
what's the deal with the plywood corner table on the water feed line?
vibration/shock isolation

That's actually a little shelf where I place a couple of bike lights for recharging (extension cord that hangs down to that spot was moved out of the way for the photo).

Eric Scheidler

pedmec said:

i would start at your backflow. the backflow has a screen on the inlet which will get plugged all the time. just loosen the nut on the down stream side of the valve and then turn the water on. if you get flow you, reassemble, move on downstream.

Okay, just did that, and with the valve completely open there is flow, but it's just a dribble:

Eric Scheidler

Okay, took the backflow apart, and there was a lot of crap at the strainer. This is as clean as I could get it. A little more than half clear; the rusty patch there I can't clear, and it's already getting damaged from being removed.

I figure I should replace this strainer (along with the green cardboard (?) washer or gasket that I had to remove to get access to the strainer. Is this a hardware store item, or do I need to go to the pipe supply store?

neilc

that screen will probably work good enough now, if the washer's ok,
or soak it in vinegar for an hour or 2,
i don't think you'll find the screen or washer in a franchise hardware store, maybe if you have an ole school store left in town,
and if you go to supply house, just buy the whole thing, it's easier, and not that costly.

Eric Scheidler

Okay, well, I got that strainer quite clear with CLR and found a suitable gasket at the hardware store. Reattached the inlet side, flipped the valve, and got powerful flow.

Then reattached the outlet side, and opened both valves. However, the feeder is still not filling the boiler. So we must have a clog in there, too. Damn, thought I'd solved this one.

So what's the best next step? Remove that plug from the 45º angle piece coming from the feeder and see what's in there?

neilc

yup,
see what's on that screen also,

keep chasing that water flow

pedmec

Did you hear the rush of water flow into the piping when you opened the ball valve before the backflow? Just want to make sure its letting water thru after you sealed it up. I would have preferred a replacement because its not guaranteed to work and with a new backflow you can eliminate it as a trouble maker.

Keep working downstream and clean the wye strainer at the feeder. After you clean the strainer disconnect the union after the downstream ball valve and test. If no water there is possibly two causes. Solenoid stem is broke or the flow restrictor after the strainer is plugged. The restrictor looks like a faucet washer and limits the amount of flow into the boiler. On the outlet side of the wye strainer sits the flow restrictor. Just unscrew the nut and the restrictor will be exposed.

Actually, you could have one more restriction. that black pipe and fitting after the water feeder.

Eric Scheidler

Success!

I wasn't able to solve this issue last season, so I had to continue keeping the boiler filled by way of a hose connected to the boiler drain. Pain in the ****, but it worked.

Today I took the water feeder apart, cleaned the solenoid gasket and all that, and still no flow.

Then I tried the last possible answer, suggested by @pedmec above: "Actually, you could have one more restriction. that black pipe and fitting after the water feeder."

That was it! That little black pipe was all filled with gunk. Screwdrive and air compressor cleared it out, and now it's feeding furiously!

Thanks Pedmec and all who helped me isolate and repair this blockage!