steam boiler sight glass

[Battis]

The sight glass on my steam boiler is filled with water. Draining the boiler doesn't move the level at all. The furnace works fine but I can't tell how much water is in it. The heating company is pretty booked this time of the year - they can be here in December. Not a big deal - I have a wood stove.
Anyways, how hard is it to remove and clean the glass? Any tips?

[JSH]

They can be tricky to get out.
With water not moving in the sight glass, tells me there are a lot of other possible issues. Sounds like a water quality issue.

[Battis]

I mostly use the woodstove so the boiler isn't used that much. Last time I used it was probably in March, so I'm guessing the sight tube gets clogged up. I drained the boiler from the bottom until the low water level light came on, then I added more water. It works fine but I'd like to clear that tube.

[redhawk0]

The tube that feeds the sight glass is clogged. If you can get the top of the sight glass holder off...pull the tube (clean it out its probably rust colored)....then try to clear the tube feeding it. I'd be willing to bet its clogged with rust.

Now...if its an old boiler....and if it is that rusty...you may run into issues like rust through that can't be resolved without replacement parts.

redhawk

[Battis]

The boiler is about 8 yrs old. The water in the tube is clear, but it is probably rust and stuff in one of the valves. I've watched videos on how to remove the tube, and it looks easy, but with my luck...

[rancher1913]

there should be a valve on the top and bottom of the site glass, could be just a sloted head screw that you do a quarter turn on or a thumb turn or an actual valve handle but there will be a valve there, after the valves are off you can unscrew the nuts on the top and bottom of the glass, these compress a seal onto the glass, pull the seal down at the top after you have losened both nuts, the glass tube will slide up into the top housing just enough to pull the bottom out and then you wiggle the glass tube down and out. you might check that the valves are just off and thats the reason you cant get the water out, most of the time the valves are kept off in case the glass gets broke and only get turned on to get a reading.

[NyFirefighter357]

I'm betting your boiler is well over filled, I find it often. An easy way to check without disturbing anything is use a hose attached to the boiler drain as a water level. Raise the hose end above the boiler & lower it slow, when water starts to come out that's the level of the water in the boiler. I've seen those glass gauge valves clog up as well but I'd start there. Now why did the boiler over fill? If you have a flushable low water cut off it's hanging up and needs to be disassembled and cleaned out. If you have an electronic type the probe may be dirty. Also flushable styles have floats that fill with water over time and sink but this would usually result in your boiler continuously filling if it's sunk that bad. Also a bad domestic water coil can fill a boiler with the smallest leak over time. If the boiler uses an electronic solenoid valve a manual valve or a manual bypass feed valve they may be leaking through.

[NyFirefighter357]

there should be a valve on the top and bottom of the site glass, could be just a sloted head screw that you do a quarter turn on or a thumb turn or an actual valve handle but there will be a valve there, after the valves are off you can unscrew the nuts on the top and bottom of the glass, these compress a seal onto the glass, pull the seal down at the top after you have losened both nuts, the glass tube will slide up into the top housing just enough to pull the bottom out and then you wiggle the glass tube down and out. you might check that the valves are just off and thats the reason you cant get the water out, most of the time the valves are kept off in case the glass gets broke and only get turned on to get a reading.

Those valves should be left on so the water level can be seen at all times.

[rancher1913]

to each his own, around here they prefer them closed so that if the glass breaks you dont end up with a mess. with auto fills it could cause all kinds of problems. like the op said, his boiler has a low water light that is independent of the site glass, personally I would rather error on the side of caution.

[Hossfly]

If you don’t know where the water level is you do not run the boiler.

[NyFirefighter357]

The glass is easy to remove & clean but over time the bottom end gets thin and may break while removing it. Also the washers should be replaced if they are old. The compression of the washer with the heat of the water destroys them over a short time. If the bottom valve is clogged you can clear it by lowering the water level below the valve and removing the valve stem if you have the rods that protect the glass use one to push the clog out of the valve.

[NyFirefighter357]

to each his own, around here they prefer them closed so that if the glass breaks you dont end up with a mess. with auto fills it could cause all kinds of problems. like the op said, his boiler has a low water light that is independent of the site glass, personally I would rather error on the side of caution.

Electronics & safeties fail that is why you have a sight glass for water level inspection at a glance!

[Battis]

I attached a hose to the drain at the bottom and emptied quite a bit of water out of the boiler, enough to make the low water light come on, but the water in the tube still did not move. When the low water light is on, the furnace will not start. I added water, the light went out and the furnace kicked on. Luckily it hasn't been very cold and I mainly use the woodstove. So, as it stands now, there's enough water in the boiler to run it, and I know it's not overfilled. If the water level drops, the light will come on and the furnace will shut down. I'll probably wait and let the pros clean that sight glass.

[NyFirefighter357]

I attached a hose to the drain at the bottom and emptied quite a bit of water out of the boiler, enough to make the low water light come on, but the water in the tube still did not move. When the low water light is on, the furnace will not start. I added water, the light went out and the furnace kicked on. Luckily it hasn't been very cold and I mainly use the woodstove. So, as it stands now, there's enough water in the boiler to run it, and I know it's not overfilled. If the water level drops, the light will come on and the furnace will shut down. I'll probably wait and let the pros clean that sight glass.

One or both the valves are plugged. Don't know why it would take 2 months to get service though. The LWCO is working no real harm in running the boiler. Here you need 2 LWCO on steam boilers and 1 on a hot water boiler. Clearing the valves yourself is easy.

[Battis]

I could get them here sooner, but the furnace is scheduled for a service/cleaning in December. Like I said, I use the woodstove mostly, but it's been getting in the 30s some nights and if we're not here to keep the stove going, it's good to know that the burner will kick on and run properly. Maybe if I run the furnace more the gunk will work itself out.

[NyFirefighter357]

I could get them here sooner, but the furnace is scheduled for a service/cleaning in December. Like I said, I use the woodstove mostly, but it's been getting in the 30s some nights and if we're not here to keep the stove going, it's good to know that the burner will kick on and run properly. Maybe if I run the furnace more the gunk will work itself out.

We service 3,000 oil customers from single family homes to large apartment buildings in 3 counties with 4 of the 10 largest cities in NY. This is done with 4 guys. Scheduled cleanings start in mid April and go through Sept., this is were we get the majority of cleanings & installations done as well as any service calls that come in. Any left over cleanings go on a list to be filled on slow days. If there is a hole in the schedule they will try to fill it with a leftover cleaning throughout the fall, winter & spring. Some may not be gotten to until late spring. We do anywhere between 3-5 cleanings each a day in the summer & up to 16 service calls each on the busiest days or a combination of both. We work 6 days a week from Oct.-May. along with OT almost daily. 99% of our work is oil with the remainder being gas units. It is not uncommon to be gone from home 16-20hrs at it's peak. We service 100+ year old coal units converted to oil to the newest technology. I'm senior man and do most of the trouble shooting as well. Stay warm, Jason

[Martin Luber]

Sight glass' are interesting....l work with high pressure boilers, 2500# . All their sight glasses tell you is that yes or no, you have water in the boiler. This is because there is no flow through it and that leg is cold. Without temperature and pressure correction you hane no idea what's really in the drum. Just 2c for fun.

[NyFirefighter357]

Sight glass' are interesting....l work with high pressure boilers, 2500# . All their sight glasses tell you is that yes or no, you have water in the boiler. This is because there is no flow through it and that leg is cold. Without temperature and pressure correction you hane no idea what's really in the drum. Just 2c for fun.

That's a whole other beast. Power plant?

[David2011]

If you have to take crusty steel/iron apart Kroil or Aero Kroil is your best friend.

[Martin Luber]

Yes, combined cycle

[rancher1913]

little off topic but the thing I always found funny on boilers was tube repair. when we would get a leaky tube that rerolling did not fix it was welded and we always had to hire a welder even though we had several good ones on staff because we did not have the state stamp or insurance policy needed. the funny part was the hired welder did work that looked like an apprentice would do compared to our welds and they always leaked when we did the hydro test afterwards and had to be re done. boilers were always easy to understand but those dang absorbshun chillers were a convoluted mess.

[GL49]

little off topic but the thing I always found funny on boilers was tube repair. when we would get a leaky tube that rerolling did not fix it was welded and we always had to hire a welder even though we had several good ones on staff because we did not have the state stamp or insurance policy needed. the funny part was the hired welder did work that looked like an apprentice would do compared to our welds and they always leaked when we did the hydro test afterwards and had to be re done. boilers were always easy to understand but those dang absorbshun chillers were a convoluted mess.

We're lucky, the welders that come in to repair tubes/headers/whatever on our boilers are dang good welders. Maybe that's what makes them so s-l-o-o-o-w. They don't even move fast when a hot piece of slag, weld, used rod, anything, gets in their underwear. But doggone, they can sure weld.
Back on topic, sounds like you've got plugged lines to the sight glass. We don't run our boilers if the sight glass doesn't work, but then we've got a completely different animal than yours. We've got one level sensor that is dedicated to keeping the boiler water at it's targeted level, it also acts as a low level/high level shutdown. Backing that up are secondary switches in case the first one fails. The water level at shutdown is still viewable in our sight glass.
And just a heads-up, everything looks easy on you tube. Been there, tried that......:D

[kodiak1]

The tube that feeds the sight glass is clogged. If you can get the top of the sight glass holder off...pull the tube (clean it out its probably rust colored)....then try to clear the tube feeding it. I'd be willing to bet its clogged with rust.

Now...if its an old boiler....and if it is that rusty...you may run into issues like rust through that can't be resolved without replacement parts.

redhawk


What he said is where I would start. Been a long time since I played with a boiler but those tubes do have tendency to clog.
We were rigged so we could blow down those tubes every so often.
Ken.

[Battis]

Yesterday I was determined to remove and clean the glass tube. I asked the hardware store down the street if they had replacement tubes, and they did - they even offered a cutter if I needed one. I went into the basement, studied the setup, then for the heck of it I tapped on the bottom of the housing that holds the tube, knowing that it was probably clogged, and bingo - the water started flowing out of the tube. I know there's still gunk in there but I'll leave that for the pros next month.
Thanks for all the help and tips.

[Hossfly]

I’ve changed these sight glasses many times, with pressure and with out, as long as the valves hold with pressure your good. Agree this can be done by the home owner but cutting a round glass tube is an art and if you don’t have experience doing this best left to the pros. I’ve cut them perfectly at times and other times made a mess out of that. You can buy that glass in different lengths but best to carry to store and try to get close to correct length or let store cut it so if they screw it up you don’t end up paying for more than you need. I have on my truck sight tube glass from 11”-36” and 2 cutters and still screw up every once and a while.

[Battis]

I had my boiler serviced last month and the tech told me to drain the boiler from the bottom and refill it with clean water, and that should clear the tube. I also tapped on the bottom of the tube before he got here, and that dislodged the junk.

[.429&H110]

Nobody mentioned shut it off first.
A hot, waterlogged steam boiler can be exciting.
Don't refill a hot cast iron boiler with cold water!
Low budget installs leave you a faucet on the bottom of the boiler, steam or hydronic, the cheap valve will plug up and leak. I used a brass nipple, quarter turn valve, hose adaptor on the drain of everything I serviced or installed, water heaters, well tanks, boilers, anywhere you would find a hose bib. Nowadays I marvel at plastic valves on water heaters.

At the bottom, underneath the gage glass bottom valve, is usually, not always, a drain. Use a flare wrench to free it, it's soft hollow brass, a quarter turn will open it. If you close the top valve, you can blow water and rust through the drain. Close the bottom valve, open the top will blow down steam if you're steaming. Then close the drain, open both top and bottom and you will see a water level. Fine by me if you leave the gage valves closed, to be opened only if curious. I found a few gage glasses victims of hockey pucks but usually their daddy had it shut off this time.

youtube has some great videos of steam explosions.

Late one winter night in South Randolph Vt I found an old lady in a cold farmhouse with an old steamer. I could smell the sick oil burner from the driveway. American Standards have a window to admire the flame, I could see the combustion chamber was wet and destroyed, water coming out everywhere, no water in the glass, target wall had a big horizontal crack.
So I called my boss, asked him to drop off a new boiler. We didn't have one that big, boss said he would be right over, meanwhile for me to clean out the chamber debris, and refire the gun to it's minimum firing rate. This was forty years ago, and Roger was old back then. He showed up with a shoebox of sheep poop, the little balls kind, slimey and fresh. I wound the relief off and funneled the poop in, put the relief back on. Reset the pressure switch to minimum. The water level was halfway up the flame with sheep poop coming out the crack, smelling like a burning barnyard. Roger slowly added water, the flame melted the poop and sealed the crack, sent steam upstairs. I installed a new boiler the next day, and Roger got the bonus because he showed up... dratted Yankees.

Customers would ask me to teach them to clean their own boiler. I answered:
If you would replace your truck's brakes and let your wife test-drive it, you are good to go with oil burners. Some people cannot, should not, and must not, but that's also true of some techs I've met.
You get judgement from experience
and experience from poor judgement.

[Battis]

Turn off the furnace...well, ya.
Add cold water to a hot boiler...ah, never. Same with a cast iron woodstove - bring it up slowly.
Work on my boiler, other than draining it periodically...nope. Not Ever.
I just got a notice yesterday from my heating company - they're raising their prices for servicing to over $300. That might make people try to fix their own.

[Three44s]

Here is a steam application I bet few of the members here at “Boolits” did not know existed:

https://staheliwest.com/

Enjoy

Three44s

[Battis]

Interesting video. Heck of a steam machine. Love that wide open country.

[Three44s]

I do not raise enough hay to justify buying one but I need steam on my hay none-the-less. The cost of the one for big balers is north of $200,000. I run small balers and they finally came back out with a small unit, $100,000 (I believe).

For a big baler it would pay off quickly if you hay 500 acres or more.

Having a fire tube boiler right behind your rear tractor window gives me the hebee jeebies though!

To me a water tube style makes more safety and dollar sense for smaller amounts of portable steam in a home spun setting.

Three44s

[Battis]

I was in ND a few years ago and got talking to a nurse at a hospital about her "small" farm. I asked how big it was and I can't remember the exact acreage but it was in the thousands. Small?

[Battis]

There are videos online showing how to clean or replace the sight tubes. I never did it but it doesn't look that hard. Like I said, I drained the bottom of the boiler and tapped above and below the glass and it loosened the crud, for awhile at least.

[MT Gianni]

I was in ND a few years ago and got talking to a nurse at a hospital about her "small" farm. I asked how big it was and I can't remember the exact acreage but it was in the thousands. Small?

Large ranches are generally referred to in sections not acres. 640 acres in a section. The small family farm is long past.
Old Montana joke "Whats the difference between a ranch and a farm?" "The size of the mailbox".
Farmers generally get every federal subsidy check that is issued, ranchers don't so they have the small mailbox.

[Battis]

We drove from Rapid City to Minot and back. I was starting to believe that the earth really is flat.