Steam Boiler Water Feeder Valve FAQs

Diagnostic & maintenance questions about water feeder valves

Steam Boiler Flooding: Too Much Water Feeds into Boiler?

Water feeder is over-filling my steam boiler?

Got a steam boiler that the psi was set way too high, about 12psi.

I think the guy who did the maintenance never turned it down after leak checking.

NOW it seems the auto water feeder is leaking cause the boiler FILLS up in a day or 2 and it starts banging. Can you change the solenoid valve alone or do I need to change the entire auto water feeder?

Also, the reading on the auto feeder hasn't changed at all. On 2020-12-08 by Robert

by (mod) - excessive residential steam pressure & water feeder valve leaks?

Setting the psi over the typical residential pressure of around 0.5 psi or less on a residential steam boiler is, I agree, a mistake, sometimes also an indicator that someone was trying to force steam past a blockage somewhere in the system - and unsafe.

It's also possible - this is just a guess - that operating at abnormally high pressure pushes more steam out of steam vents, so increases water consumption rate, so increases the automagic water feeder operation.

I'm unclear on how that would itself cause the water feeder to leak - the water feeder needs to be repaired or replaced - depending on exactly what is leaking. (Sometimes proper flushing of the water feeder and LWCO will stop leaks).

You can change the solenoid or electrical parts of a water feeder valve without replacing the whole valve, but before doing so I'd want to be confident that we've properly identified the problem - to avoid the cost and trouble of having to do the job twice.

Steam Boiler Water Feeder Won't Stop Feeding Unless I Turn Power Off

I have a one pipe steam system. Peerless cast iron boiler with McDonnell & Miller Model No. 101-A electric feeder valve.

It's now snowing here in Vermont.

When I turn on the boiler's propane burners the water feeder makes a loud noise and won't shut off until I flip off the emergency burner switch(red box attached to unit).

When boiler is turned off I can push down button on electric feeder valve and it delivers water to boiler and shuts off when I release. Any help would be appreciated.
regs, On 2020-11-02 by Joe

by (mod) - Peerless cast iron boiler with McDonnell & Miller Model No. 101-A electric feeder valve.

Joe

With the apology that of course there can be a condition there that I do not understand, usually the water feeder is not controlled by the burner being on or off but rather by a float that senses the water level in the boiler and turns the feeder on when water is needed.

Yes let's start by observing the water level in your boiler. If the water is at a normal level such that the water feeder should not be feeding then the problem is with the feeder or its control circuit and you may need to turn it off and monitor your boiler and keep the water level up manually until you can get the water heater repaired.

Doing that will allow you to turn the boiler back on and have heat. Keep me posted.

Steam boiler water feeder McDowell & MIller won't stop sending water into the boiler [McDonnell?]

i have a problem with my water feeder a mcdowell & miller when it calls for water it sends it but it will not stop do i need a new water feeder??? thanks - Will

Reply:

Will, you might need a new automatic water feeder, but it's an expensive part to buy and install. I'd try flushing the valve thoroughly to see if that clears up the trouble.

If that doesn't work, before replacing the valve ask your steam heat service tech if s/he can open and service the valve.

Frequent cycling of water feeder: found leaky steam piping in hidden condensate return line

You advice on looking for a leak in the return lead me to a length of pipe that looked like swiss cheese on close inspection.

The system is over 100 years old and the old return in the basement behind a wall was leaking where I couldn't see it. I had the pipe replaced with copper and all is well. No more low water cycling. Thank you for your good advice. - Bob Q from Brooklyn

Reply-DF:

Thank you for the follow-up Bob, your report will help other readers who are trying to track down steam boiler water loss problems.

Have problems with filling the water to right level in a steam boiler

I have 3 year old peerless stam boiler. i use to fill with water maybe once a day. now im filling this boiler every 2-3 hours! i see no leaks no smoke . i even filled the boiler turned it off and came home from work to find the glass valve showing only 1/4 full! where is this water going? (Jan 3, 2013) mgrant

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I have a Weil-Mclain gold oil system. Think it's pretty old as it is manual fill. (Bought house in August) I know I also have a tankless hot water coil. (Jan 25, 2013) Lani

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When tank goes out. (I'm assuming that I'm not filling this often enough.) I then flush the system & fill the water level up in sight line. Then within about 4 hours it shuts itself off again and have to re-boot the thing. This has happened every time the system shuts off. Probably about 1 a month.

Also--I noticed that after I fill sight line, turn back on-the sight line water level fluctuates heavily. What does this mean?

Also am I suppose to maintain some kind of psi pressure even when I have the tankless hot water coil? I dont know how to maintain this. It's usually at 0 then after a episode it might go to 2-3 psi. v

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Newly installed (within the last week) Williamson OSB -3 Checked the sight glass, there is a misshapen piece of metal in the glass. It looks like it might be solder that broke loose. Should I call the installer on an emergency basis? This is Saturday night. (Jan 27, 2013) Giovanna

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I have a steam boiler. The problem. After a day the sight glass is full to the top with water. I have to drain 2 pales of water out of the boiler everyday just to bring the sight glass back to the half way level. The next day the same thing. The sight glass is all the way full. Now I flushed the bioler, it did not work. Next I replaced the waterfeeder, it still did not work, and last I replaced the low water cut of part. And it still does not work! What else can it be? What else can I try. (Mar 23, 2013) Lisa

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I just bought a home and in the inspector's report it says that I should the boiler is equipped with an automatic water feed unit.

It goes on to say that this type of unit is prone to malfunctioning and could cause flooding of the system if not cleaned and checked periodically. My question is, how often should I have it checked? or cleaned?

Reply to all of the above:

Everyone: see STEAM BOILER FLOODING / SURGING REPAIR

Giovanna,

It sounds as if an automatic water feeder on your steam boiler needs cleaning, adjustment, repair or replacement.

Lisa,

I'm surprised that a home inspector would suggest that an automatic water feeder is a bad idea on a steam boiler - the device is a significant safety improvement as well as one that reduces the amount of homeowner maintenance and attention to the steam boiler.

But she is right if the inspector told you that the system needs periodic inspection and flushouit. Usually the low water cutoff valve or LWCO is flushed on a residential steam boiler once a week; some homes can go longer, some need more frequent attention.

The difference depends in part on how much water your boiler system consumes and thus how much new water is fed into the system.

If I were buying a new home with a steam boiler I'd ask my heating service company to send out one of their steam experts to go over the boiler with me, giving me a more clear explanation than I seem to have gotten from my (your) home inspection report as well as to give advice on how often this particular boiler should have its LWCO flushed.

Daniel Friedman

McDonnell & Miller Unimatch Water Feeder Won't Stop Feeding Water into the Boiler

Installed 24v Unimatch water feeder. Worked for past ten years. Now feeder will not stop feeding water into boiler.

Replaced the Unimatch with new one, and still have the same problem. Took wires off of unimatch from safeguard lwc and feeder is still powered and is feeding water continuously.... any ideas? On 2017-12-20 by john

Reply by (mod): Start troubleshooting at the LWCO then check the water feeder control manual

I suspect that you've made a wiring error.

Watch out: the wiring for these WFE Uni-Match water feeder controls varies depending on the low water cutoff LWCO Model that is wired to work with the Water Feeder valve. A table of wiring diagrams for each WFE - LWCO combination will be found in the installation and instruction manual for your water feeder.

But first check your LWCO Low Water Cutoff control as that device may be stuck in the "send water" mode. LWCO valves need periodic flushing / cleaning.

See LOW WATER CUTOFF VALVE NOT WORKING 

If you don't already have it, review these M&M Uni-Match water feeder manuals

• McDonnell & Miller WFE Uni-Match 323 ELECTRIC WATER FEEDER INSTRUCTION MANUAL [PDF] (2008) (at Sid Harvey, an HVACR Supplier) - local copy saved as MM-Uni-Match-323-Water-Feeder-Manual.pdf
• McDonnell & Miller WFE Uni-Match 323H ELECTRIC WATER FEEDER INSTRUCTION MANUAL [PDF] (2019) (at Xylem.com) - local copy saved as MM-Uni-Match-Water-Feeder-Manual.pdf

If you need a different Installation / Operation Manual for your water feeder valve

see STEAM BOILER WATER FEEDER VALVE MANUALS

If you don't have the manual for your LWCO

see LOW WATER CUTOFF CONTROL MANUALS

McDonnell & Miller WFE-24 calls for water when below water level but it just jerks on and then off immediately.

Hi, My Steam boiler was losing water pretty fast the past 2-3 weeks. I think I have it nailed down to radiators hissing constantly.

FInally tracked down replacement valves.

Problem now is that the McDonnell & Miller WFE-24 calls for water when below water level but it just jerks on and then off immediately. INdicator light and gauge glass let me know it is still sensing low water condition. Could the thing have loveped out from overworking so consistently the last couple of weeks? Meant lucked out" from overworking. On 2017-03-05 by Kevin N.

Reply by (mod) -

Agree, Kevin: if the radiator never stops hissing then its steam vent is probably clogged, not closing when it should, and we're wasting water.

It also sounds as if your water feeder or low water cutoff or both need cleaning.

Water feeder valve won't stop putting water into the boiler

I installed an automatic water feeder on my steam boiler but when I open the water valve, water continues to flow through the water feeder and never stops can somebody tell me which one is the problem. On 2017-12-03 by Jorge

Reply by (mod) -

Jorge,

Watch out: Overfilling a steam boiler will cause loss of heat and risks damage to the system.

Normally a steam boiler will have a line or mark on the boiler face or on the sight glass in front of the boiler showing you the recommended water level when you are manually filling the boiler.

I suspect that your installation is incorrect or you have left a valve or control in the "open" position instead of in the automatic position.

Start by finding the installation instructions for the specific automatic water feed valve you've installed, and there you'll find, usually at the end of the manual, troubleshooting tips.

See STEAM BOILER WATER FEEDER VALVE MANUALS

For safety I urge you to have your system inspected by a trained Steam Heat service technician. The tech got also review with you the proper operation of the boiler including when and how to feed water.

 

What are the consequences of over-pressure in a gas fired steam boiler (too much water) ?

Tell me the consequences of having too much pressure in a gas boiler (refill tap left on ) - (Feb 15, 2015) Edd

Reply: boiler flooding, no heat, unsafe

Anonymous

That sounds unusual; on a steam boiler if there's a leak that's losing water that fast it'd most likely be close to the boiler.

If you don't find a leak I suspect a debris-clogged water level sensor or a failing switch; I'd call for service. Also check the level in the boiler.

Some things to check

Blocked condensate returns
Condensate return leaks
Steam vents that do not close when the radiators are hot

Watch out: When you flood the steam boiler by putting in water above the water line indicated at or near the sight glass, the boiler can't produce steam or if it tries to boil all that water it's boiling water up into the steam distribution piping. Steam can't reliably rise to the radiators and the heating system may be unsafe.

You or your heating service technician will drain the boiler back to the proper level.

How do I drain an over-filled steam boiler?

What can you do if there is too much water in glass tube. How can you drain the water to appropriate level ? (Oct 2, 2015) debbie

Reply:

With the boiler COOL so as to avoid SCALDING BURNS the boiler drain might work.

Watch out: even touching a boiler drain that hasn't been touched for years can be a catastrophe: you may open it and find it won't close again.

Leaks at Steam Boiler Water Feeder or Low Water Cutoff?

How do I Find & Fix Leaks at the Steam Boiler Low Water Cutoff LWCO?

I replaced my leaky old low water cutoff valve in my steam boiler.

When I begun refilling the boiler to start the unit, the water started to leak again from the new low water cutoff valve after I added about 3/4 gallon or so. On 2019-03-03 by Samir

by (mod) -

Look closely to find exactly where the water is leaking: from the valve drain port (then the valve is not shut) or from a piping connection (improper installation) or from the valve body (damaged or modified valve)

by Samir

Thanks. I slowly allowed the water in. It is clearly coming off the front rim. from behind the 8-hole ring.

Worth mentioning is that I was unable remove the old brass housing. So, I am using as it seem to be well. However, there one old screw head that is broken in the rim holes and about 1 millimeter is protruding off the rim.

So, I screwed in the remaining 7 screws. Your advice is greatly appreciated. Please elaborate on how the valve can be shut. I am also trying to remove the lodged broken screw.

by (mod)

It sounds as if you need to remove that broken screw.

To do that you may have to drain the system, remove the control, and then hopefully that will be enough of the broken screw exposed that you can grab it with vise grips and unscrew it. You might try a little liquid wrench on the screw first.

by Samir

Thanks again, I was able to install the LWCO as I made sure the rubber washer ring was in place. No leak is there. Now my problem is that the electric connection is not working properly as the unit will not start as I turn the switch on.

Reply by (mod)

Is it possible that the switch float is stuck? Did you try flushing the valve?

by Samir

Mod, Thanks, I had the LWCO lined up with the existing electric box port direction.

This caused the float to be east and west instead of north and south. We had to correct that and it worked. I am guessing the new LWCO was designed different than the old one. It was an error on my part.

by (mod) - proper installation of low water cutoff fixes float jamming

Samir

WAY TO GO in finding and fixing the problem of float movement that caused the LWCO to fail to work properly.

I'm actually surprised that it was even possible to mount a control such that its float movement would not respond properly to boiler water level, and I'd appreciate seeing some sharp photos of the valve and boiler (you an attache 1 photo per comment using the Add Image button.

Danel Friedman

Automatic water feeder going on every 4 minutes - is this too frequent

The automatic feed turns on every 4 minutes on my steam boiler to add water. Is this too frequent? Do I have a leak? (Feb 11, 2015) Anonymous

Reply: yes, something's wrong

Yes, something is wrong: either the feeder is not actually feeding water or there is a leak. Check the water level in the sight glass.

Broken boiler gauge, leaky boiler, no water, no heat

My gauge broke on the boiler and I have a leak and heat will not work. What do I do? - (Feb 13, 2015) russ

Reply:

Wow - this is more than one can fix by an e-text. You need an on-site service call to see what repairs are needed for your steam boiler.

Watch out: with the boiler sight glass broken, unless valves into the top and bottom of that sight glass work and can be closed completely, you can't even put water into the boiler - as it will just leak out. In that condition the boiler cannot be operated and is unsafe.