Leaky siteglass

TwoTones

Just had the site glass on my steam boiler replaced 2 yrs ago.  Noticed today it is leaking from top packing nut down the glass when under pressure.  My question is, should I try tightening the nut or am I going to break the glass? I don’t have extra glass and have never installed one….  It is a small leak, wondering if I should just have a pro come after holidays or if I should try and fix myself?  

109A_5

Hello @TwoTones,
Not a good weekend to intentionally break your boiler. If you are not prepared to repair it if the sight glass breaks, I'd wait for a pro.
Or wait and order the almost unbreakable thicker glass version and then you have a spare if it does break.

ethicalpaul

Or if you break it, you can always close the two valves on it. You won't be able to see your water level but the boiler will run.

Pumpguy

IME, its unlikely you'll break the glass by giving the compression nut a slight tweak.

On vacuum systems I sometimes see bubbles rising from the bottom up to the water level. This indicates a slight air leak at the bottom grommet. A bit of tightening on the lower compression nut stops the bubbles.

I have yet to break a glass doing this.

Dan_NJ

Pumpguy said:

On vacuum systems I sometimes see bubbles rising from the bottom up to the water level. This indicates a slight air leak at the bottom grommet. A bit of tightening on the lower compression nut stops the bubbles.

When I had a one pipe steam system and serviced the sight glass I would wait around long enough after a call for heat - the minute or thereabouts after shutdown when that system would drop into vacuum briefly - to make sure there were no such bubbles. Also keep in mind you won't see any bubbles if it's the top grommet leaking under vacuum. So if you have a vacuum leak like this and bubbles, probably a good idea to repeat whatever tightening you need to do on both the bottom and top grommets.

EBEBRATT-Ed

@TwoTones

I sometimes hesitate to give homeowners advise on some repairs but this is something you can easily do and save some money.

Order some 5/8 gauge glass and some gauge glass rubber washers and a gauge glass cutter. You might find them in a big box, a good plumbing supply store or some hardware stores.

If not you can get them from supply house.com shipped to your house:

1 pkg. #H1-10 gauge glass Quantity 6 x 10" long

(3) H7-23 gauge glass nuts, rubber washers and steel washers

(1) 1801006 Cutter

The above will cost you $60 + shipping and you will have enough for 10 years

If you old glass is only dripping a little let it don't touch it until you get the new stuff. As @ethicalpaul said you can run the boiler with the glass shut off temporally but you do need to see the water level.

Once you have the stuff you can tighten or replace as needed.

The way to get the glass the right length is to (shut both valves and remove old glass) insert the glass into the top valve until it bottoms out. And make a mark at the bottom of the glass with a black sharpie where it will just meet the top of the threads on the bottom valve. Cut the glass about 1/16 shorter than your mark. Or measure against the old glass if it is the correct length.

Assemble with nuts washers etc.

Just go hand tight then just 1/8 of a turn with your pliers.

STEAM DOCTOR

Typically, measuring face-to-face and then adding 3/8 of an inch will do it.

STEAM DOCTOR

But that's typically and that's why you always have extra glasses on hand 🤣🤣🤣

TwoTones

Thanks for all the advice, going to wait until after holidays, thanks to useful supply house list I will change it myself and have extra glass on hand. Only a small leak, only noticed it bc it whistles when the boiler first shuts down and goes into slight vacuum… 

TwoTones

This is a testament to how great this forum is, successfully changed site glass to discover the plumber who installed it did a terrible jagged cut.  Had to be leaking from day 1 and just got worse.  When he installed it, the top of the glass fogged up with a lot of condensation on inside.  When I asked the  plumber said I was just actually seeing what’s going on in boiler bc glass is new and it will clear up.  

   So thankful I can talk to people who actually know what they are talking about on here and do simple jobs correctly….  Never hiring that plumber again..   

pecmsg

Things happen it's how they deal with it that counts. This plumber handled it wrong.

TwoTones

He replaced the whole gate valve site glass assembly.  My guess is he got a kit that came with one piece of glass so he tried to make it work..

EBEBRATT-Ed

@TwoTones

The plumber probably showed up with one glass. Once it is too short your screwed.

Some people may be better at cutting the glass to fit than others. It's a good idea to have some spares. even with the correct cutters thy can be difficult and you will break one occassionally.

My success rate is probably 70%

ChrisJ

STEAM DOCTOR said:

But that's typically and that's why you always have extra glasses on hand 🤣🤣🤣

I've tried to get @ethicalpaul to have a few on hand but he keeps breaking them 

pecmsg

EBEBRATT-Ed said:

@TwoTones

The plumber probably showed up with one glass. Once it is too short your screwed.

Some people may be better at cutting the glass to fit than others. It's a good idea to have some spares. even with the correct cutters thy can be difficult and you will break one occassionally.

My success rate is probably 70%

Im still 50/50

ChrisJ

I cut one a hair long but ground it down on a belt sander.

Chris_L

My supply house cuts them to length, which is a great help.

retiredguy

If you are going to cut your own gauge glass I would recommend that you use a "chain cutter" and not one of those with the long shafts that cut on the inside of the glass and make sure that you use oil on the cutting wheels. Remember this, your success rate is never 100% when cutting gauge glass.

JUGHNE

I save the scraps so I can practice before cutting the real one.
Use a chain cutter maybe once a year, so need to practice.

EBEBRATT-Ed

I hate the chain ones. I was told they are for electrode porcelains' although people use them for gauge glasses.

I have better luck with the small ones that look sort of like a tubing cutter.

ChrisJ

I think this is the same as what I used

https://www.amazon.com/dp/B07QBMRHQ3/ref=sspa_mw_detail_0?ie=UTF8&psc=1&sp_csd=d2lkZ2V0TmFtZT1zcF9waG9uZV9kZXRhaWwp13NParams

TwoTones

Guess I got lucky because I am not experienced but I got a great cut my first time.  Used the 1/4 turn wheel cutter.  

109A_5

Hello @TwoTones,
Years ago I went with these products, with the hopes of it never breaking again or otherwise needing to be replacement if I removed it for cleaning. The glass was custom cut for my old boiler. So far no leaks and I have not had to take it apart.

PYREX TUBING SIGHT GAUGE GLASS 5/8" 16MM OD X 9MM ID EXTRA HEAVY WALL 4MM
https://www.ebay.com/itm/362675380047
TEF-LON GAGE GAUGE BOILER SIGHT-GLASS PTFE GASKET WASHERS SET - WILL NEVER LEAK
https://www.ebay.com/itm/370994428128

And it seems there is even thicker wall products out there now.
'HEAVY-WALL' (5.56 mm) Boiler Sight Gauge Glass 5/8" OD, 8-1/4"~12" w/ 2 Gaskets
https://www.ebay.com/itm/363963239522