Sight glass installed too high? No water visible in glass

bipbap

I recently found a real steam guy in my area and am prepared to follow his advice but just wanted to get a second opinion for safety sake.

There are times when my boiler will be running and the water will become not visible in the sight glass. I immediately shut it down and add water once it’s cool.

My steam guy said in my case, no water in the glass isn’t a true indicator of the water level in the boiler because the sight glass pipe isn’t reading straight out of the boiler because the pipe elbows up a couple inches, throwing off its accuracy by a couple inches of water height which means if the glass was dropped down a couple inches it would probably read right in the middle of the glass where it should.

Check out these photos and let me know if this all makes sense. Again I trust this guy and he seems to really know his stuff so I’m just trying to get a second opinion for my own peace of mind.

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Big Ed_4

The old feeder was raised to bring up the water level. Maybe aside arm or condensation loop in the past ? The water level is now controlled by the electronic unit now … You can cut that old unit out , it is not wired in , and lower the glass back down …

bipbap

ok thanks

So then it does make sense that in this particular setup the water disappearing out of the sight glass isn’t as worrisome as it would normally be?

(Tho obviously still somewhat worrisome since I don’t have a way to read just how low it goes)

Just fyi- once the boiler cools down the sight glass is about 20% full.

109A_5

Hello bipbap,

Yeah that is odd.

I would say it is accurate but not showing the proper range of water level.

Looks like there is two LWCO (Low Water Cut Off) units, M&M electronic and a M&M cast iron LWCO. What they did is they wanted the shut off water level (or auto fill) of the M&M cast iron LWCO a bit higher for some reason, is there an auto feeder.

EDIT: I looked at the other picture, looks like the OLD auto feeder was disconnected.

So instead of connecting the sight glass to the Tee port directly off the boiler where the plugs are in the Tees for a normal view of the boiler water level they connected it to the M&M cast iron LWCO's tee assembly. Very odd.

So both the M&M cast iron LWCO and the sight glass is offset up maybe about 2 inches the actual water level shown is the same as in the boiler. If the sight glass was in the correct position connected directly to the boiler tapping provided by the boiler manufacture the water level would look more normal.

If it was mine I would either move the sight glass in the off session or just add a second one to the correct spot.

Kind of a poor picture edit but maybe you get the idea.

EdTheHeaterMan

Nice cut and paste @109A_5. I noticed that extra tee and street elbow that lifts the water line 1.5" based on the old M&M 47-2 LWCO and feed. BigEd noticed the probe LWCO is doing the job at the lower water level.

109A_5

If the old LWCO is not wired as a redundant, but totally out of service I would remove it and put the sight glass where it belongs. Less weirdness.

ethicalpaul

There are times when my boiler will be running and the water will become not visible in the sight glass. I immediately shut it down and add water once it’s cool.

So I'm not clear. Where is the level when the boiler is at rest? And then you say "there are times" it goes lower below the bottom of the glass? Is the level moving considerably during a call for heat?

bipbap

Thanks for all the comments guys, real helpful.

Ethicalpaul, the inactive water level is about 20% of the sight glass. It does move considerably, going down the full 20% so to be not visible in glass. Another issue in this is water loss which I haven’t been able to figure out and that this boiler is oversized I’d imagine for its current setup.

My guy suggested dropping the sight glass to the proper level and adding another electric LWCO as I think it may be code in my area to have a backup. I think he disconnected the old float LWCO.as it was unclear if it was even working properly.

Jamie Hall

Well, in my opinion your steam guy is right…sort of. The sight glass should be more or less centred on the operating water level in the boiler — which should be marked on the boiler. And then the water should always be visible in the sight glass. I would be uncomfortable if the sight glass was set like yours, with part of the safe operating range effectively out of sight — and since changing it is pretty simple, I'd do that at the first opportunity.

Big Ed_4

So you need two LWCO on your system ..

I like 109A's option of moving the gauge glass assembly down to the run of the tee .. You may want to instal a short shaft gauge to get it closer to the actual water line…

JUGHNE

Could the intent of adding the Tee's and nipples have been to add clean outs for that port and to get the sight glass above the lower sludge point?

BTW, there are some boilers with a label/sticker line, below the lower sight glass connection, that say "Lowest acceptable/operating level".

Like a gas gauge on your dash board that has "1/4 tank" as the lower point of indication……you don't know what you got.

109A_5

JUGHNE

" Could the intent of adding the Tee's and nipples have been to add clean outs for that port and to get the sight glass above the lower sludge point? "

With that type of gauge glass, properly installed, you can just remove the valves and usually do clean out with the a gauge glass protection rod. With the added vertical offset it would make total clean out harder.

TKPK

for years my system operated at LWCO and would refill only enough to satisfy LWCO. It was always short bursts of water fill and probably a lot of interrupted burns because of low water

there was no water line marked on the boiler that I bought new in 1991. WM EG-65.

Now I operate the boiler between 65-75% of sight glass range. The boiler and I are much happier and now all burns are 15+ minutes and occur ever 70-80 minutes. I installed a VXT and set the refill to 2 gallons which takes it from LWCO trigger level to a nice operating level. It would only get interrupted cycle one time before it got put back to its “happy place”.

It has not filled at all this season but I did test it a couple of times when I was skimming and treating the water.

Just because your LWCO is very low on the sight glass does not mean it should operate at that level but as others have said, you should be able to see the water level all the way through the operating range.

EBEBRATT-Ed

Just so everyone is aware of this. A sight glass has to be mounted straight shot into the boiler with no elbows. You can have couplings and tee off to a LWCO (like a #67) but you can't turn the sight glass.

You can't put a sight glass on a boiler and come out of the boiler with a nipple into a 90 and put the sight glass on the 90. Can't put the sight glass on the branch of a tee either.

This is an ASME code thing.

being able to see the water in a steam boiler is pretty important. Putting in a bunch of 90s or 45s just makes it more libel to plug up. And you certainly are not supposed to change the elevation of the sight glass.

That has always been the rule with steam if you can't see the water level it's not safe to run.

EdTheHeaterMan

@TKPK said: there was no water line marked on the boiler that I bought new in 1991. WM EG-65.

Yes there was. The original installer was supposed to affix it to the boiler at 23-13/16" above the boiler floor. If you still have the manual in the original envelope it was shipped in, back in 1991, you might find it stuck inside there.

If yopu cant find it, you can go to Staples and get a Sharpie marker and draw a line at 23-13/16" off the floor. It will serve the same purpose.

bipbap

Thanks for all the insight guys, really very helpful. This place is such a great resource.

JUGHNE

I meant that perhaps the Tee installer was concerned with the boiler ports getting plugged and therefore added "clean outs".

Yes, I have cleaned/replaced numerous sight glasses.

And I add the " Gordo/Silent Steam Team" blow down valves to all the sight glasses I service.

109A_5

I think they wanted the old LWCO / auto feeder to operate at a more normal water line level, instead of the typical close to minimum level, so they raised the old LWCO. Where they kind of went wrong is they should have kept the sight glass gauge in the normal position.

Now since the LWCO / auto feeder system is probably just using the newer newer electronic LWCO and is mounted in an actual boiler taping the water level when minimal is out of range of the old sight glass position.

I'd normalize the whole thing, and remove what is not being used. In the mean time I'd figure out where the 50% point is where the sight glass gauge should be and manually keep the water level close to that point and not rely on automated minimums.

pedmec

Old timers used to do this when we had the old everhot side arm tanks to flood the coil to get more hot water. Gets more of the coil under water so they can get more hot water out of the system. use to see this every now in then.

TKPK

@edtheheaterman
I’m just saying the water line sticker wasn’t installed by WM or by Williams (or Williams removed it which I don’t believe) who was the installer. The sticker is not in the still very complete package of manuals of absolutely everything that is installed on the boiler that I keep within 10’ of the boiler.

As I said, for 33 years of its life the LWCO and the water feeder that fed only enough to satisfy the LWCO decided how much water was in the boiler. The techs that came and serviced the boiler for the 1st 10 years never put on a label or said a word about water level.

I did the basic servicing for the next 23 years and it operated the same way. My boiler flooded a few times during the last season and I decided to replace my very rusty water feeder and bypass valve that had a hodge podge of galvanized, brass and copper, I will post a picture when I get to my phone.

Only by coming to this site and reading a few of DHs books have I understood this was not correct. I wish that wasn’t true because I could have saved several hundreds to maybe $1000+ per year for those 34 years. As I have seen with almost every HO post, how it should be installed and how it is installed is not always the same, even by the “pros”. Shame on me for not reading the manual more thoroughly each of those 34 years.

I know where the designed water line is now and it is marked and monitored, even with a camera as I spend the winter season away from the boiler.

I cannot express how much I appreciate the help and insight that is provided by the pros on this site.

EBEBRATT-Ed

If you don't know exactly what the mfg wanted for a water line you run 1/2 a glass. It's been that way forever.

Does anyone think the old asbestos covered coal fire robots or snowmen had water level marks? Maybe under the asbestos and they also (some) had try cocks to verify the water level if they did not trust the gauge glass.