Boiler keeps calling for water, sight glass full

tmeric7

I was awake this morning when the boiler wanted to kick on. It started by calling for water from the auto feeder. That was weird. By the 3rd time it ran, I was in the basement. Sight glass is full, so it seems like ther is an error in the low water sensor? Just to get it to stop (and get some cloths on) I disconnected the signal wires at the auto feeder. I suppose I will investigate the low water sensing, but I am a novice here. Any help is appreciated!

JohnNY

Are you sure the sight glass is full? It looks empty. The low water cutoff is showing a "low water" red light condition, so it's making the feeder feed water. And you have some other problems like those two hose spigots: one at your shins and one waist high. They need to go. Have full-sized valves installed in their place.

tmeric7

The sight glass was/is definitely full.

Update:

I flipped the boiler circuit off/on at the breaker. The low water light went off and the boiler fired up. So I'm happy that I am warm, but a few questions remain:

1. Why would this happen/how do I prevent it in the future?

2. I drained a fair bit of water out after all the auto fill cycles. Is there something that will override the constant feed requests at some point? (Something to say "Oh God, no more water!")

3. I've noticed water draining slowly form the sight glass recently and with this episode there is now a bunch of crap in the last 1/2 inch of the glass. Is there a preferd way to clean that out?

4. @JohnNY I don't mean to defend the spigots (they were there when I bought the house), but what is the problem with them? They aren't seeing any significant pressure.

Thanks,
Tristan

Jamie Hall

Seems to me that it is time for you, if you are handy, or a really competent steam pro. to take the sight glass off and make sure that both openings from it into the boiler are really clear. Then check and make sure the pigtail is really clear. Then check and make sure the low water cutoff is clean and working properly.

Then see where you go from there.

No, there is no way that I know of for an autofeeder to sense that it's feeding too much water in too short a time. One can't use a simple count, after all -- it has to be a rate, and they don't measure that.

eclark

Regarding the autofill there are plenty of discussions on the wall about how they can mask a water loss issue for a long time by keeping the boiler topped off with fresh (oxygenated) water, which then can speed the demise of the boiler. The recommendation from many is to bypass or disable the autofill, and then to keep an eye on the water level and manually filling it only when needed. If that isn't practical for you, there are water meters you can add to monitor how much water is being added by the water feeder over time.

On my own system there wasn't an autofill when I bought the house. I had to leave my house unattended in the coldest part of winter for a couple of weeks so I installed one, and the one I used was a McDonnell Miller model that will run the fill cycle a few times over a certain period if called by the LWCO. If the LWCO continues to call for additional water beyond that limit, the autofill requires a manual reset to limit flooding the boiler. When I'm home and able to check the water level regularly the autofill is disabled.

tmeric7

Thanks Jamie! Since my last post I did remove the sight glass and clean it out. It was all full of crap. It's clean and clear now... very satisfying. I did also make sure the pigtail was clean. Check and check on those two.

As for the low water cutoff... I can pull that out and whip it down if it's cruddy, but is there anything else? Any way to test it besides draining the boiler, see that it turns on, then is satisfied on reaching water level?

Umm, so what happens if the auto feeder keeps cycling when I'm not around to notice it?!

Jamie Hall

It would be a good idea to pull the cutoff and make sure it's nice and clean, but when you reinstall it -- no tape! At most a thin smear of compound. It has to have good metal to metal contact on the threads.

The test is simple. With the boiler running and the autofeeder valved off, drain the boiler down and see if the burner shuts off (it should). The autofeeder should be trying to add water -- open the valve and see if it does. Further, the autofeeder should stop adding water when the low water cutoff is happy, and the burner should start again. Refill the boiler to the half way mark on the glass.

Now. Autofeeders. There is a diversity of opinions on them. On the one hand, if they are working properly they are nice to have. On the other hand, if they don't have a meter on them, they can conceal leakage and add water as needed -- but to the detriment of the system. Further, on occasion they will misbehave and add way too much water. What I would suggest is that you valve the autofeeder off and turn it off electrically, and then keep an eye on the water level in the boiler. That way you will know how much water your boiler is really using. If it isn't using all that much -- say less than a gallon a week or so -- you might be best off leaving it off, and just checking the level and refilling manually when needed. The downside to that, of course, is if you or another responsible party are going to be away for a while, you might run low on water -- at which point you are depending on the low water cutoff to work (you only have one?) and you would have no heat. And if the low water cutoff doesn't work, you might dry fire the boiler which is even worse. That can ruin your whole day...

tmeric7

Thanks. I removed the cutoff probe (it was in there tight!) and cleaned it, though it was not incredibly dirty. I also cleaned the electrical terminals at the probe. I knew not to use tape from the manual, but I didn't have sealant, so I just stuck it back in there.

Testing seems to indicate it works fine... now.

In my experience the autofeeder runs rarely, and only when a lot of steam leaves the boiler (starting up on a really cold day). Also, I'm very aware of when it runs (as long as I'm home) because I can hear it anywhere in the house. All this started with me lying in bed thinking... "hey, why is the autofeeder running?"

Thanks,
Tristan

nicholas bonham-carter

Why not leave it valved off for a few days to see if you have any excessive water loss. check it every day or so.--NBC

Gordo

I'd add a proper sight glass drain valve, replacing the not-very-good drain cock that is there now. It really helps with sight-glass maintenance and you will be less likely to be caught off guard in the future as to what your boiler's water level truly is.
https://www.youtube.com/watch?v=OgKAO8s8QBE

JohnNY

The hose spigots should be full size valves to allow for skimming of the surface-laden oils at the top of the water line, and at the lower tapping, for flushing of collected sediment.