Boiler over filling.
So this boiler probably went in in the mid 80s. It's piped wrong but has been working without issue until last fall when the VXT feeder started overfilling. It's not passing water through the feeder or the valve so it is actually calling for water. Delay to feed is maxed out to ten minutes. It's controlled with a vaporstat at 12oz.
I'm thinking the 1960s 1" return line is probably clogged. Could it be that this piping is suddenly causing the water to be pushed out even those it's worked for years? The house actually heats great, no banging, surging, or any issues other than this.
Comments
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So does the level go down during operation prompting a call for more water? What does the sight glass say as the boiler goes through its cycle?
Trying to squeeze the best out of a Weil-McLain JB-5 running a 1912 1 pipe system.0 -
When was the last time all of the controls were cleaned? Does it happen if you keep the boiler filled manually?
Could be the return is clogged, the float in the lwco is sticking and calling for water even after it is filled, possibly vaporstat pigtail plugged and pressure and pushing water out of the boiler.
Water surging because oil got in it, water priming from additives or change in water chemistry.
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I've only ever watched it for about two hours. Site glass may move down a little during that time. Ive never actually witnessed it feed. Seems to be almost random. I should add the LWCO is a Miller style float (67). It's 12 years old, they empty a cup of water every other week and it seems to function properly.
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Has the LWCO been taken apart and cleaned?
I'm saying that because a test is to turn off the auto feed and you really don't want to do that if you're not absolutely sure the LWCO is working and will turn the burner off.
Trying to squeeze the best out of a Weil-McLain JB-5 running a 1912 1 pipe system.0 -
You should blow it down in to a bucket until the float drops and turns off the burner when you test it then fill it back up. it may be getting stuck there or the connections to the lwco may be clogged so it keeps feeding once it trips. You should be keeping it filled without relying on the feeder.
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I had to replace the head on the MIL's Mod 61 LWCO this fall due to a bad switch. Same effect- overfilling but would trigger on fall just fine.
Trying to squeeze the best out of a Weil-McLain JB-5 running a 1912 1 pipe system.0 -
The low water cutoff does work. It turns off and on as it should. Pigtail is cleaned or replaced yearly. Vaporstat verified functioning properly.
Haven't tried to see what it does with the feed closed. It certainly won't overfill as I've visually verified no water passing the valves and it only happens with heat on. I know the easy answer is manually filling. It's an early woman who isn't physically able to go down and deal with it.
I'm assuming the water is being pulled or out not returning for some reason. I can't get it to do it for me though. My next step is to repipe the return through the finished basement and might as well correct the near boiler piping while I'm doing it.
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It could be the feeder float hanging up — as noted the proper blowdown is probably at least a gallon or so. It could also be that wet return clogged — they do…
Br. Jamie, osb
Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England0 -
I'm not sure what you mean by "I'm assuming the water is being pulled or out"
What would pull the water out?
NJ Steam Homeowner.
Free NJ and remote steam advice: https://heatinghelp.com/find-a-contractor/detail/new-jersey-steam-help/
See my sight glass boiler videos: https://bit.ly/3sZW1el0 -
That's what has me scratching my head a little. Theres been times when it has happened twice in 24 hours. I can't imagine it actually going off on low water and calling that quickly.
If the return was clogged I would think it would just be clogged not work so times and not others.
When this happened late last winter it was right after the previous owner moved out. I couldn't recreate it or find any obvious cause. my assumption was that the previous occupant set the thermostat at a temperature and left it. When the house was empty, they would let it cool down to 50°, come over for a few hours and crank the thermostat up to 75. I figured that coupled with the incorrect near boiler piping was somehow preventing the water from returning or pushing it out. Now with the new occupant, she says she set the thermostat and never touches it. So that theory is out the window. This boiler also did sit and run all summer for the domestic water coil without incident.0 -
That's what has me scratching my head a little. Theres been times when it has happened twice in 24 hours. I can't imagine it actually going off on low water and calling that quickly.
If the return was clogged I would think it would just be clogged not work so times and not others.
That does sound more like surging.
This boiler also did sit and run all summer for the domestic water coil without incident.
For hot water production it only heats up to 180 or whatever, it doesn't make steam and won't surge
NJ Steam Homeowner.
Free NJ and remote steam advice: https://heatinghelp.com/find-a-contractor/detail/new-jersey-steam-help/
See my sight glass boiler videos: https://bit.ly/3sZW1el0 -
I meant that if it was a leaking feeder or leaking bypass valve it would have still overfilled during the summer. The feeder itself is pretty much ruled out.
It could be surging but I'm not convinced. I've watched it run and that water level stays pretty solid. At worst it moves smoothly maybe a quarter inch up and down. No reports of any odd noises, banging, etc. nobody has done any work to it that should add oil or contaminants.
It's a small house. The main is just under 40' of 2". If this was the water getting pushed out of the boiler shouldn't it still make it back in ten minutes before it feeds? Just throwing thoughts out there. Maybe a combination of a slow return and surging.
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More and more I'm thinking slow or clogged return…
Br. Jamie, osb
Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England0 -
My old tiny boiler would surge and the water would go below the gauge glass. It would return fast, but there were several gallons in the main at any given time.
NJ Steam Homeowner.
Free NJ and remote steam advice: https://heatinghelp.com/find-a-contractor/detail/new-jersey-steam-help/
See my sight glass boiler videos: https://bit.ly/3sZW1el0 -
A close look at the boiler shows a mixing valve just behind the set of instruction manuals hanging on the water feed pipe. That indicates to me that there is a tankless coil in that boiler somewhere.
Im going to go out on a limb here and say that VXT feeder is not over feeding at all. Im going to say that the tankless coil may have a pin hole inside the boiler. The test for that is to shut off the Domestic Hot Water cold feed valve and see if the overfilling stops. It is the orange handle valve in the photo.
If you still get overfilling, then you need to install a valve in the Cold In port where indicated. If the mixing valve holds the cold inlet closed (as it should) then closing the cold feed valve to the DHW coil will tell you if the coil is the problem.
Edward Young Retired
After you make that expensive repair and you still have the same problem, What will you check next?
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you are correct that the boiler has a hot water coil. It went all summer without overfilling. This leads me to think that the coil is OK. I suppose it's not impossible that there's some kind of leak which seals itself at 180 and opens up at Steam temperatures.
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We're all spinning our wheels unless you do some testing as recommended above.
Trying to squeeze the best out of a Weil-McLain JB-5 running a 1912 1 pipe system.
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When the coil springs a leak in a steam boiler does not depend on the date, or the weather, or the boiler temperature. A leak can start at any time. If that leak started at about the same time as the start of the heating season, that would only be a coincidence, not a cause and effect scenario.
I suggest that since you already eliminated the feeder as the source of the overfilling, (you did the broken union test), then you now try the "Leaking Coil Test".
You will all want to take your shower at one time (separately or together, No judgment here), then close off the cold feed valve to the DHW after the last shower. You will not have hot water for the duration of the test. Watch to see if the water level rises. If the water level does not rise, then open the cold water feed to the DHW. when the water level rises then you have found the coil has a leak.
Since your mixing valve cold inlet can not be turned off, and there is a possibility that it will not close off the cold inlet port 100%, you should add a ball valve where I indicated in the photo above before doing the "Leaking Coil Test".
Edward Young Retired
After you make that expensive repair and you still have the same problem, What will you check next?
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It was doing this in the early spring, was fine all summer and now it's begun doing it again that the heat is back on. It only happens when it's making steam. Thats why I don't think it can be the coil.
I think there's another valve above that will shut the coil feed and the boiler feed I'll give it a try.
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You are probably correct.
Edward Young Retired
After you make that expensive repair and you still have the same problem, What will you check next?
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Which tests? I'll try whatever but I think it's all been covered.
•Shutting off the auto feed will solve it as the boiler has no other source of water.
•Low water cutoff has been checked for proper operation.
•Pigtails and vaporstat been checked.
•Feeder has been checked for leaking through as has the bypass valve. It was actually replaced already.
•Pretty sure the coil is good as it only does it while heating but I'll check anyway.It's not impossible the low water cutoff is doing something whacky intermittently.
Could that 1" equalizer tied into the 18" or so run to the return drop be keeping water from getting back for as long as ten minutes?
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Is it surging? Your earlier description of what was happening made me think it might be.
it's hard to tell without a glass pipe, I'll give you that.
NJ Steam Homeowner.
Free NJ and remote steam advice: https://heatinghelp.com/find-a-contractor/detail/new-jersey-steam-help/
See my sight glass boiler videos: https://bit.ly/3sZW1el0 -
If the wet return were clogged, you'd get low water on every cycle.
Another thing to check: is every radiator valve open? Old closed valves can allow steam to enter, condense and then flow back to the boiler flooding it at some later time.
Try closing the supply to the auto fill and only fill the boiler manually .
Trying to squeeze the best out of a Weil-McLain JB-5 running a 1912 1 pipe system.
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This. Make sure the new occupant is opening the valves all the way or closing them all the way. Partially closed valves will tend to make the radiator collect condensate.
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Agree- I'd leave them all open for testing. "Closed" doesn't necessarily mean they're really closed.
Trying to squeeze the best out of a Weil-McLain JB-5 running a 1912 1 pipe system.0 -
Not visibly in the gauge glass when I r seen it run. It has maybe a quarter inch of smooth movement if that.
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This is somthing I haven't checked. I will look at it. All running smooth the last several days though.
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Well I believe I finally caught it in the act.
The McDonnell 67 is working fine. The float moves freely and it turns the boiler on and off as it should. It was calling for water with the boiler running and the water level well above the cut off. The switch in there must be doing something funky. Replaced the LWCO and we'll see how it goes.Thanks for the input everyone.
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