Weil-McLain EG-85 cutting out mid cycle

speedbird

Hi everyone, have recently noticed from time to time that my boiler (one-pipe steam) seems to just shut off mid cycle, even while the thermostat is still calling for heat. It happened the first time last year, and I notice it happening now, maybe once a week.

Boiler was installed in 2004 and runs amazingly well, quiet balanced heat, people have said it's been installed perfectly. We have it serviced annually. The gas valve was replaced in 2019. Pressure seems fine. Water level seems fine. Automatic damper seems fine. Thermostat seems fine. Installed in an open space, so should be getting plenty of air.

Is there a heat/flame sensor that could be failing? Maybe gas valve wasn't installed correctly? Could there be an issue with gas feed/pressure? WH and dryer run fine. Any ideas?

Jamie Hall

This is steam… and I see that your pressure is set right down at the bottom of the scale. I'm going to bet that it's cutting out on pressure; the cutout is likely to be around 1.5 psi which won't register on the normal 0 to 30 gauge.

speedbird

Thanks @Jamie Hall

Yes, one-pipe steam.

That cut in setting (at bottom of scale) has been set like that since its as installed. Are you suggesting I try and raise the cut out setting? I don't see where to do that? I'm also concerned with changing stuff like that given how well it been's running for 20 years.

This seems to be a new phenomenon that started happening last year.

EdTheHeaterMan

Do not change the pressure setting

There are many things that can cause the flame to turn off on your Weil McLain boiler. The obvious ones are the pressure control. if the pressure in the boiler reaches the CUT IN pressure plus the DIFF setting (that is on the inside of the control) then the pressure switch opens and the flame stops. If that is the case, and it has been working fine for 20 years, then leave it alone. It is supposed to do that.

Another reason for the flame to stop during a call for heat is the low water cut off control. That control will shut off the flame if the water in the boiler drops below a safe level to operate the boiler. That will turn the flame back on when the water level rises back up to a safe level. (from the automatic water feeder or from the condensation returning to the boiler after the steam heats up the radiators)

Other things are the spill switch on the vent connector pipe that goes to the chimney. if the chimney is blocked and the fumes go inside the house you don't want the flame to keep making fumes that can make you sick or kill you. you fix that by having the chimney cleaned or a blockage removed. There are roll out switches near the flame inspection opening. If the boiler gets plugged up with carbon, and the fumes from the flame can't go up to the vent connector to the chimney, those switches will stop the flame from burning. to fix that you need to clean out the carbon from the heat exchanger (if that is the reason for the burner stopping)

Another reason is the flame sensor no longer detects the flame. After years of operating in the hot flame the sensor rod can become corroded or even burn away. The fix for that: you need to clean the flame sensor or replace the flame sensor if it is burnt away.  

EBEBRATT-Ed

I will bet it is the low water cutoff. Keep the boiler water level at 1/2 a glass and see if that helps. In your picture someone marked the glass with a black Sharpie your water level in the picture is well below that mark.

Keep track of how often you have to add water. Too much additional water means you have a leak or your vents are passing steam.

EdTheHeaterMan

I made an edit above with more details.

All of that can be handled with normal maintenance. when was the last time a professional maintenance was completed? the LWCO you have has a sensor insidethe boiler that can fet dirty and fail to operate properly. the flame sensor in the flame can be cleaned and there are some Steam Boiler items that you should look into, like flushing sludge from the wet returns and the bottom of the boiler. Cleaning the pigtail that the pressure gauge is attached to. There is a whole list of maintenance items that need to be completed on an annual basis or maybe every other year.

Have you maintained your equipment properly?

speedbird

Thanks @EdTheHeaterMan and @EBEBRATT-Ed, with regard to LWCO, I've always just assumed the water levels are ok because we have an automatic water feeder, that I hear running from time to time. So wouldn't those two devices (working together) be keeping the water levels high enough?

I also noticed when this happened yesterday the water looked especially dirty and was bouncing a bit. Maybe the bouncing is causing it to dip below the LWCO? Going to try draining it, and manually adding water to get it closer to the sharpie mark on the glass.

I don't think we have any leaks, all the vents are quiet and all the piping in basement is visible. I guess we could have a leak in a wall somewhere, but I don't think so.

EdTheHeaterMan

"I've always just assumed the water levels are ok because we have an automatic water feeder, that I hear running from time to time. So wouldn't those two devices (working together) be keeping the water levels high enough?"

That is the idea of that combination of parts.  The fact that your water is jumping up and down in the glass and that water in the glass is a little cloudy, tell me that your maintenance is past due.  When was the last time anyone tested the pH of the water in your boiler?

@ethicalpaul can give you some DIY tips here, and you should look at his latest video on making your steam boiler last forever. 

speedbird

hi @EdTheHeaterMan, have had an annual service since we moved in about 11 years ago. Here's a list of what was done this most recent service. I think this covers most things you listed.

EdTheHeaterMan

https://forum.heatinghelp.com/discussion/comment/1823979#Comment_1823979

Looks like you are up to date. I didn't see any water testing on that list. You may want to research @ethicalpaul and his steam boiler videos.

https://www.youtube.com/%40pb7379-j2k

especially this one

https://www.youtube.com/watch?v=Im1ipgVa6Yk

TKPK

I have very nearly the same boiler and had the same situation.

First thing I noticed is your water level is down near LWCO as others have suggested. My old feeder would just open until the lwco was satisfied and there was a renewed call for heat. That keeps you right at the minimum but not good operating level.

My new VXT lets me decide how much to add and I have found that 2 gallons above LWCO is the right amount. It also lets me delay 4 minutes so I know (most) all the water is back from the returns and equalizer.

the other thing that I changed is a setting on my thermostat. It was reacting to a 1.2F change in temp with “fast” setting. I changed it to the “slow” setting which is a 1.5F change in temp.

Doesn’t sound like much but it has completely changed how the boiler is being asked to fire. Before the single call for heat would be interrupted 2x. Now I have one continuous burn.

I might change out the thermostat to a middle level Honeywell model that allows only one call for heat per hour but since it is behaving nicely now, why bother.

I would sit and watch the boiler and could see that the water level was above LWCO and have a 0-5” water gauge so I knew it wasn’t pressuretrol. Only other possibilities are flue and spill as far as I know.

Robertw

There is also the intermittent level test to consider. I believe this shuts the burner down after 15 minutes of operation regardless to just confirm there is water.

EBEBRATT-Ed

@speedbird

If you have a water feeder that feeds very often then you have leaks. Don't forget you don't need to water to have a leak. A steam leak is a water leak. You can lose water from steam vents, packing nuts around valves under floor returns if you have them.

Its important that you don't add too much boiler water it can shorten the boilers life.