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Steam boiler - water overfilling

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mike212
mike212 Member Posts: 50
edited December 2017 in THE MAIN WALL
I have a mystery that I need to solve. It might be as simple as I just need a new automatic water feeder, but I prefer to avoid the expense of changing it and finding its not the issue.

I've been in the house for 1.5 years, this is my second heating season.

Oil heat
Steam boiler (Weil McLain)
small section of baseboard heat runs in basement off the boiler. Taco circulator pump.
Mcdonnell&miller low water cut off

On a rare occasion, the boiler water feeder runs way too long and fills 20 to 30 buckets worth of water. First time water leaked out of the main valve (which I then replaced). Another time water leaked out of the lowest rad valve after the main. In the past I have only caught it after the water stopped filling. Today for the first time I caught it as the issue was happening and stopped it when it only got 2 buckets over filled.

Today when I saw what was happening I turned off the boiler at the switch and the water stopped filling. I drained 2 buckets out so the water back back at the proper level, flipped the switch and the water started again so I flipped the switch off. I turned off the water valve and flipped the switch back on. In less then a minute I began to hear a motor running - i think it was the auto water feed trying to supply water but failing due to the valve being shut. I flipped the switch back off.

A couple hours later, with the boiler cooler, I switch it on and the water is not feeding in.

I have yet to isolate a reason, its happened about 6 times in the last 2 heating seasons (2 this year and the rest last year). Both last year and this year it happened on the first day we turned on the heat.

Today when it happened the heat was already on and the rads were already luke warm before the boiler run so it wasn't a cold start. The only thing different from a normal day today is the baseboard heat was turned on, but I don't believe it was currently pumping when this happened. The baseboard heat is quirky so I don't normally leave it on. It will stop pumping after about 10 minutes if the boiler is above 190. I guess the pump overheats. It doesn't reset until I turn the thermostat off wait 10 minutes (always need to wait even if the pump has since cooled) and then turn it back on. Today the baseboard thermostat was on, but I'm 99% certain the water wasn't pumping, but I'm not sure if it wasn't pumping because the pump stopped or the thermostat was no longer calling for heat.

Just before I heard the automatic feeder running, I noticed a radiator was producing a lot more heat than normal and it seemed slightly steamy. This is in the attic, far as possible from the boiler. My wife heard the automatic feeder running too long and called me and that is when I got to the basement turning it off.

I will take some pictures and add them to this post in a few minutes. Any ideas?




Comments

  • mike212
    mike212 Member Posts: 50
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  • Fred
    Fred Member Posts: 8,542
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    When was the last time you took that MM #67 LWCO apart and cleaned it? It has a float inside and that float could have a small leak in it but most likely is hanging up on crud that builds up on the inside walls of the unit itself. They should be scraped out once a year. You need to order a gasket set before taking it apart.
    mike212
  • mike212
    mike212 Member Posts: 50
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    Ripping that LWCO apart and getting it all back together may be well beyond my skill set. My heating oil company came out as part of the service contract, opened up a nut on the top, stuck a metal stick in and tried to move things around. They said maybe its the LWCO but its not cheap to replace.

    I'll wait and see what happens. If it does it again I I'll do some research into how to take the LWCO apart and clean it. Then if I can't get it back together I'll just need to have them install a new one which is the same place I'm in now.
  • Fred
    Fred Member Posts: 8,542
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    It really isn't a big job, if you have any mechanical where-with-all and pay attention to how it came apart. You are correct, if the float has a leak and is water logged, that float cost almost as much as a new MM #67. I doubt it is that though. If it were, the problem would be more consistent. Probably just needs a good cleaning and sticking a wire in the top is not the fix.
    Don't put off a relatively low cost repair until it fails when you aren't home and you have that to fix plus a lot of plaster, floors, carpet, and whatever to also deal with due to water damage.
    mike212
  • EBEBRATT-Ed
    EBEBRATT-Ed Member Posts: 15,616
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    1. #67 is not that hard to clean
    2. #2 your service company is an idiot,
    Call the service manager and complain or call another service company. Sticking a rod down through he 1/4" pipe plug hole does nothing but possible damage.

    This is a safety control that need service. It needs to be taken apart and cleaned or replaced. Screw around with it not knowing what to do, lazy service technicians could cost you a boiler

    Your choice
    mike212
  • mike212
    mike212 Member Posts: 50
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    Okay thanks, I'll look into cleaning it.