Furd,

That's my intention- however I have a similar problem of boiler overflowing. I do blow down low level cutoff valve weekly and try to keep the system clean. I noticed, when I do blow down, automatic water feeder turns on for while until the level reaches about 1/3 of the glass. Then it turns off for a few minutes, and then turns on again filling the water up to 3/4 of glass. At this point I just have to close the manual valve to stop further feeding and keep it closed. Sometimes when I stop by the boiler, I see green light on water feeder, which means it would feed the water even when the level is already high. My concern is if I miss a low level and cutoff valve would malfunction and would not shut down the boiler, it could lead to very bad consequences.
Does the above look like a problem of the feeder or a stacked float in the cutoff valve?

 

I'm glad someone read my long-winded reply.
[I read ALL your long-winded replies! - NJT ed.]

Without knowing what type (float or probe) of low water cutout you have or how it is piped to the boiler I can't offer anything concrete. Please post some pictures of your setup and include the manufacturer and model of your feeder and low water cutoff(s).

To post pictures you need to first upload the pictures to a photo hosting site such as photobucket.com or villagephotos.com. and then post the public URLs for the pictures (or album) here. More pictures are always better than fewer. Please have CLEAR pictures and have both close up pictures and ones from a far enough distance that we can see how the various parts are interconnected.

 

Hi, Furd,
Thank you for your reply. I uploaded some pictures to Picasa Web Albums - Lazar - Water feeder

They show McDonnell and Miller low water cutoff (model 67) and water feeder WF2.
It used to work for years, it's just this year it began overflowing, so I had to close the output valve of the auto feeder. As I mentioned, I noticed even when the level in the glass in high (above half) the green light on the feeder sometimes is on. When I am testing the feeder by blowing water down, it turns on, feeds some water, then turns off for a few minutes, and then turns back on even though the level is already normal. I am trying to figure out if it's a problem of the float in low water cutoff or a faulty feeder.
Thank you for your time.

 

Hi Lazar, Как дела?

I don't know much about steam stuff... but I'm wondering if the 'off levelness' of the feeder has anything to do with it malfunctioning?

How those things work?

 

Yeah, the pipefitter who installed that baby must have really tied one on the night before.

Here is the instruction manual for the latest incarnation of that water feeder. http://www.bellgossett.com/literature/files/7423.pdf As you can see it has a few features to prevent overflowing and I suspect that your unit also has at least some of these features.

It is possible that the valve assembly inside the feeder is leaking but I'm more than a little afraid that you have partially obstructed passages in the connections between the Model 67 and the boiler. It looks like the Model 67 has been removed and replaced in the not too distant past. If this is true do you know if the passages into the boiler proper were cleaned?

BTW, if that pressure gauge doesn't have an "internal siphon" (it will so state on the gauge face) it is toast. Gauges don't like steam internally.

 

Quotes of note from that I&O manual:

 

Furd and NJ Trooper,
Thank you for your replies.

Yes, the 67 low water cutoff was already replaced several years ago. I don't know if the pipes from 67 to boiler were cleaned. The manual in the link you provided states "Feeder will be deactivated when water level is restored to level as determined by LWCO. NOTE: McDonnell & Miller Series PS LWCO's have a 15 second DOM (Delay on Make) to restore water level in boiler to an appropriate level without overfeeding."
I've been checking the system today and caught a moment when the boiler was off, the pressure was zero as shown by the gauge [which means the burners were off for quite a while], the level in the glass was higher than half, and yet, the feeder's LED was steady green, which means as the manual says open solenoid [so it would feed if I did not keep its output valve closed].

I don't know what circuit WF has to control the solenoid, but I understand it is supposed to be activated only by a signal from LWCO. This makes me think either float stucked inside, or water level in the LWCO is lower that in the glass because of an obstraction, as you suggested. So, for now I'll concentrate on LWCO area.
A side note: I did not see any reference to "internal siphon" on pressure gauge. Maybe that's the reason the gauge shows up to 6 psi while my pressure valve is set to 2 psi.
Thanks again for your input.

 

Probably... and you can mount the gauge on a tee next to the pressurtrol, or it's own siphon tube to correct that.

 

Yeah, the feeder piping is skewed. I don't know if it affects anything though, since the signal to the feeder comes from low water cutoff valve- the feeder itself does not "know" what's the water level in boiler.

 

I did read up on that a little after I posted that. You are probably right... it does sound like the LWCO is telling it to feed.

 

There is no question that the LWCO is sending a signal to the make-up water valve, the question is WHY is it sending the signal.

In my opinion it is either a failing float, failing switch or plugged connecting piping. Since the Model 67 is fairly new I vote for the plugged connections.

One possible, but I think unlikely cause could be damaged insulation on the connecting wiring. If this was fifty years ago when rubber/fabric insulation was more common on wiring I would say it was definitely something to look into but unless someone used ancient wire OR forgot the anti-short bushings on the armored cable I rather doubt it is a wiring problem.

 

Take the end cap off the LWCO where the wires are at. There is a roller switch in there.
Those roller switches can come apart. inspect this switch. you can take a screw driver and
operate the float up and down. This will tell you if the float is working freely. You could have a pin hole in the float so it is taking on water, if so float would get to heavy, switch would stay made. This switch is what makes the feed valve.
You can buy the parts separately to rebuild that LWCO. There are open contact points on that roller switch that can get bad and stick. Later Paul

 

It's good info and all... but please allow me to point out that the original poster may not even be monitoring this thread from last year.

 

Paul,
Thanks for the useful suggestions. I'll try to do it, probably by the end of the heating season- I am afraid to mess with LWCO at the middle of the winter. At least it shuts down the boiler when water is low. For now I keep feeding water manually.
Regards,
Lazar

 

Yes, this was the case. I drained water, removed the LWCO back panel, disconnected four wires and removed the float. It was very greezy and greeze was inside the chamber too. So, I had someone replace the float assembly (for reference, it's McDonnel & Miller p/n 6667) and it now works fine (so far...).
Thanks again everyone for your input.
Lazar