Sight glass leaking

KayMac

I recently had my boiler serviced (also had 2 Big Mouth vents installed) and now the sight glass is leaking water and steam when it runs when it didn't before. I tightened it on the top and bottom and it didn't help so I assume that the washers are shot. The old main vents never shut so I wonder now that I have these new awesome vents that close when they should it blew out some crummy old washers.

Is it safe to run this way? Should this be a service call or can I replace the washers myself? I am keeping an eye on the water level and adding as necessary (I know this isn't a good thing).

BobC

You can do that yourself, pick up a new sight glass and a set of rubber washers and the thin brass washers that go with them. Do not take anything apart till you have all the parts in hand. make sure you get the right diameter and length of sight glass.

This is best done with the boiler off. Turn both valves off, loosen the nuts and remove the old and replace with the new.

https://www.amazon.com/Crown-Packing-everything-repair-leaking/dp/B013ID4M40/ref=pd_bxgy_328_2?_encoding=UTF8&pd_rd_i=B013ID4M40&pd_rd_r=AWVCA5A8RTWZ5BWE3T2B&pd_rd_w=pa7Kg&pd_rd_wg=CzP7Z&psc=1&refRID=AWVCA5A8RTWZ5BWE3T2B

Bob

Ironman

Close the red valves, loosen and move the compression nuts and lift the glass upward and the bottom will come out of its socket. Then pull it downward and out. Check the washers. If they're still flexible and not cracked, try re-assembling after cleaning everything.

Koan

Agree with @Ironman, on removal technique - I did mine that way but had to cut the new glass myself - easy to do. Make sure the new glass has a little play like the old one

You can try this also as a supplier, this is where I got mine to replace it. First work I did on a boiler.

supplyhouse.com/sh/control/search/~SEARCH_STRING=gauge%20glass

or here:

supplyhouse.com/sh/control/search/~SEARCH_STRING=boiler%20gauge%20glass


Agree with @BobC , don't start until you have the new glass, new compression washers and new brass washers at hand. If you have to cut a length of gauge glass it is really easy. You can use a gauge glass cutter or a triangular file to score it just once and then snap it away from you. Low cost and for piece of mind. My glass cracked on removal (or already was and came apart) but I taped it back together to use as a template for the new glass length.

https://youtube.com/watch?v=-X0AcjyCXZ0

Abracadabra

just in case it's not obvious, remove the protection rods to get easier access to the nuts.

KayMac

Thanks for all your help. The weather finally let up here and I was able to shut the boiler down to cool for a bit. With all your excellent directions I was able to carefully remove the sight glass, the washers were very brittle and crumbling. I replaced them, cleaned the glass and reassembled everything safely without breaking the glass. It is running now and not leaking...Yay!

marcusjh

I've noticed that over time, the glass deteriorates and gets really thin. I replaced mine not long ago, and i could not believe how thin the bottom edge was. It was like the tube had been sculpted down into a razor thin edge. I'm guessing it's from the calcium in the water. According to the service tech's notations, it shows 5 years is about the max we can go on a sight glass.

Fred

Yes, I've seen that on mine glass to. I assumed it is just erosion from the water moving up and down that half inch or so on each heating cycle. I suppose it would be more or less aggressive depending on water hardness.

KayMac

I noticed that on this sight glass also, it looked like the glass was shaved down. I guess I am very lucky it didn't break when I put it back together.

BobC

I always keep a spare sight glass on hand, you never know.

Bob

MilanD

William McLane glas I have is very thick. I just had it cleaned when we had the section replaced, 7 years, the thing is rather thick.

Fwiw, I did notice WM replacement glass from supplyhouse.com was more expensive from several other ones offered. Perhaps it's bc it's thick.

Fred

I keep a spare on hand too. It is a really thick one too. When I need to replace the one that's on the boiler, I will use it. It's not much of an issue. They regular ones last typically five or more years.

PinkTavo

My boiler is circa 1981...the previous owner (when it was a commercial use building) likely never did any service to it. I have lived in the place since 1996. I don't believe the sight glass has ever been changed. Maybe I have one of the thick ones!

EBEBRATT-Ed

@MilanD , @Fred . We had a job once that we couldn't keep gage glass's in without leaking. 25psi HP steam.

they wouldn't last a month. Turned out it was the PH of the water etching the glass

ChrisJ

Friends, let's call it a gauge glass.

KayMac

Thanks. I'm just a home owner and not sure how to describe what I was looking for but it brought some awesome answers and helped me correct the problem.

nicholas bonham-carter

What's wrong with sight glass?--NBC

ChrisJ

nicholas bonham-carter said:

What's wrong with sight glass?--NBC

Perhaps nothing and I could very well be mistaken but my understanding is a sight glass is typically what is used in refrigeration, or to view the oil in a crank case of a pump etc being nothing more than a flat glass window.

At least from what I've seen the manufacturers seem to always call what we have a gauge glass.

Of course, both terms could be both 100% correct, I don't know.

Gauge glass sounds cooler?

ChrisJ

https://en.wikipedia.org/wiki/Sight_glass

Perhaps both terms are correct.