Steam Boiler Sight Glass Q&A #2
FAQS: clean, use or fix the steam boiler sight glass

Steam boiler sight glass questions and answers, set #3.

This article series describes how to find & use the sight glass (or sight gauge) on a steam heating boiler to check or set steam boiler water level.

Steam Boiler Sight Glass Repair FAQs #2

These recently-posted questions & answers about the sight glass on steam boilers appeared originally at SIGHT GLASS, STEAM BOILER - be sure to review that article.

On 2018-11-11 by Mike F. - Bad ball valve floods steam boiler

So.. It was discovered that one of the new on/off ball valves was defective, allowing the water to by-bass the VXT auto feeder.

The water feeder is not bad, as first thought. I'll check the water level in an hour or so to make sure that it's not rising again. Hopefully this will be the end of this nightmare. I'll say a prayer.

On 2018-11-11 by (mod) - Bad ball valve floods steam boiler

Mike what are the diagnostic things I forgot to ask you is whether or not this boiler includes a tankless coil for making domestic hot water.

If it does and if that coil is leaking that would be adding water to the boiler independent of a problem with the automatic water feeder.

Other problems that we look for are delayed condensate return because of the kind of said return blockage or clogged,

And other steam boiler flooding problems that you will see in our article on flooded steam boiler repair

STEAM BOILER FLOODING / SURGING REPAIR

On 2018-11-11 by Mike F.

I can't believe this, but I checked the boiler and it's still slowly filling up with water !

Placed another call for the service guy to come back and try again to figure out what's happening. Thhe glass tube was filled all the way. I drained out about 4 buckets of water. This seems to be an unending nightmare.

On 2018-11-11 by Mike F.

I drained about 14 buckets of water out of the boiler earlier this morning, until I could see a true water level in the glass tube ( half way up ).

I fired up the boiler and watched it for about 20 -30 mins. The water was slowly rising again. I shut it down, and drained two more buckets out of the boiler.

After a few hours of rest I took a look and the tube was all the way up again.

Drained 18 buckets out and found some bad flooding by the radiator in the basement. Second time I had flooding this week.

First time was after they installed the new LWCO and Auto feeder earlier this week. Steam and water was leaking out of the top of the viewing tube, and a new joint that they installed by the water feed was also leaking. This morning the repair guy arrived and after some testing he discovered that the new VXT 120 auto feeder is defective.

It was allowing the water to slowly enter the boiled, but showed no gallons being used. He has bypassed it for now until they can come back and install a replacement later this week.
I not feeling to good about these guys.

I hope they can really fix this thing for good. I already sent them a check for the full amount of the installation of the new equipment that they installed ( $ 942.00 ).
Do you think I have a case to ask them for a credit on my account for the all of the problems ( flooding, no heat or hot water )? If so, what would a fair amount be?
Thank You,
Mike F.

On 2018-11-11 by (mod) -

Mike that sounds like an installation or adjustment error that may have flooded your steam boiler. I'd ask the company to return, drain the excess water from the boiler, and check the adjustment of the automatic water feeder and the position and operation of its water level sensor.

Other possibilities are a tankless coil leaking into the boiler OR a bad control or valve or water feeder leaking into the boiler.

Let me know what you're told, and post a photo of the full sight glass, of the boiler, the LWCO, and the VXT water feeder (one image per comment) if you can; that may permit us to comment further.

On 2018-11-11 by Mike F. - my steam boiler is flooding after installing a new Safeguard 450 LWCO

I just had a new safeguard 450 lwco installed, and a vxt auto water feed installed on my steam boiler. The old mechanical lwco failed.

The water level in the tube is now all the way up, and there seems to be no steam reaching the radiators. The pressure gauge reads zero. The basement is very warm though. Is the boiler over filled with water? Should I call the service company back to look at this?

On 2018-10-30 by (mod) - it is normal for the sight glass to look empty

No, Gloria. Perhaps there is a condensate return clog.

On 2018-10-30 by Gloria Vergel

it is normal for the sight glass to look empty when the boiler is running, or it has to have water always while is on or off

On 2018-08-18 by (mod) - Should the sight gls control valves ne opened or closed

Normally opened so that you can monitor the water level in the boiler.

Closed if the sight glass is broken or leaking - pending repair.

On 2018-08-18 by Karen Snyder

Should the sight gls control valves ne opened or closed

On 2018-04-15 by (mod) -

Check the float condition and float level - the float that senses boiler water level could be improperly placed, or installed, or may be slow in responding.

On 2018-04-15 by james

MY glass gets over filled by my automatic refiller is there aything I can do to adjust it

On 2018-03-24 by (mod) - when to check the sight glass water level

Richard:

When the boiler has been off for a time after you added water, check the sight glass again. If water level has risen above the point to which you added water, then we think there is a blockage and a delay in return of condensate to the boiler.

If that's not happening I'd look for a problem with steam vents that are not closing when the rads are hot, or for a leak in the condensate return line.

On 2018-03-24 by Richard

I have a Crown Boiler, all Of a sudden the water keeps emptying out of the sight glass which in turn shuts of the heat to radiators, Can anyone help, I keep filling it up to the mark, when I run the heat for 30 Mins the glass empties

On 2018-02-22 by (mod) - You can add water to a hot boiler but WATCH OUT

You can add water to a hot boiler but WATCH OUT: don't add much nor too fast or some boilers (cast iron in particular) could be cracked - costly or ruinous damage.

If you have to add water to a hot boiler, add it SLOWLY and you'll be ok.

On 2018-02-22 by Sean

Do you have to have the boiler off and cold to add water or should it be hot and running to add water?

On 2018-02-11 by (mod) - steam boiler can run with no sight glass - but ...

Yes, Dennis, the steam boiler can run with no sight glass - you have to turn off the upper and lower valves and then confirm that there is no leakage. That's a reasonable emergency measure to keep heat on while waiting for the repair person to replace the sight glass.

Watch out: with no sight glass you cannot visually monitor the boiler to assure that the water level is proper and safe. Some steam boilers using automatic water feeders may still work just fine.

On 2018-02-11 by Dennis

Can boiler still run without sight glass? Do I turn off upper & lower valves on sight glass, I also counted to 50 to reduce water in boiler, so it doesn't overflow boiler.

On 2018-01-25 by (mod) - Leak on valve of sight glass

Anon:

TEMPORARILY you can close the valves at the sight glass - to see if that will stop the leak while you wait for your service tech to replace or repair the leaky valve.

On 2018-01-25 by Anonymous

Leak on valve of sight glass

On 2018-01-06 by (mod) - The water level sight glass is hot. Is that ok?

Thats normal

On 2018-01-06 by John

The water level sight glass is hot. Is that ok?

On 2017-12-10 by Denise

Boiler temp gauges levels. What should be be set at.

On 2017-11-07 by (mod) - Should the both the top and bottom sight glass inlet valves be fully open to operate prooerly

Nice question, Paul, I will do some research, but I'm guessing that as long as the valves are open at all the boiler water level gauge or sight glass, whose purpose is only to show boiler water level, will work fine

. It's possible that people close the valves to reduce surging in the sight glass;

It's also possible that a partly closed sight glass valve may be more prone to clogging.

I suspect some people might stop down the valves to reduce surging of the water column in the sight glass. In my view that's not the best "repair" even though we discuss it in the article above on this page.

If the boiler is surging that might cause other trouble. More on surging is at STEAM BOILER FLOODING REPAIR https://inspectapedia.com/heat/Steam-Boiler-Flooding.php where we point out that surging can foul the water feeder.

Also at CHEMICAL TREATMENTS, BOILER https://inspectapedia.com/heat/Boiler_Chemicals.php we discuss boiler chemicals added to control surging.

And if the valve is closed too much, a nearly-closed inlet valve crud in the boiler could more easily block water entry into the sight glass, rendering it inoperative.

I think the main use of those little valves is to permit changeout of a broken sight glass or to keep the boiler running (by closing the valves) while waiting for a broken sight glass to be repaired.

On 2017-11-06 by Paul

Should the both the top and bottom inlet valves be fully open to operate prooerly

On 2017-09-07 by Umar

Can a boiler work without Qatar lavel indicator

On 2017-04-23 by (mod) -

Anon:

Thanks for the question. Please see my very detailed reply now found at

https://inspectapedia.com/heat/Steam-Boiler-Flooding.php

On 2017-04-23 by Anonymous

What causes high water level readings in the site glass.

On 2017-04-22 by (mod) - Is there water in the pipes when the boiler is not running

Steve:

no, not if your heating system is steam heat: heat rises in the form of steam passing through the supply piping and as the steam cools and condenses back to water that condensate reuturns to the boiler.

When the boiler is OFF the condensate should have returned and the only pipes that would contain water would be the condensate line where it is lower than the boiler's water level (Search InspectApedia for HARTFORD LOOP to see how that condensate line is arranged)

If you have a leak at a flange connection then you should be able to replace the gasket.

yes if your heating system is a hot water (hydronic) heating boiler and radiator or baseboard system.

On 2017-04-22 by Steve

@Steve,
If there is a dresser coupling that is dripping can I just replace the o ring

Is there water in the pipes when the boiler is not running

...

Continue reading at SIGHT GLASS, STEAM BOILER - topic home, or select a topic from the closely-related articles below, or see the complete ARTICLE INDEX.

Or see SIGHT GLASS, STEAM BOILER FAQs-3 - more-recent Q&A on how to diagnos and fix problems with the boiler sight glass and water level

Or see these

Boiler Water Control Articles

• BOILER CLEANER CHEMICALS / TREATMENTS
• BOILER LOW WATER CUTOFF CONTROL LWCO MANUALS
• LOW WATER CUTOFF VALVE, BOILER
• LOW WATER CUTOFF VALVE NOT WORKING
• LOW WATER CUTOFF CONTROL MANUALS
• SIGHT GLASS, STEAM BOILER
• STEAM BOILER FLOODING / SURGING REPAIR
• STEAM HEATING SYSTEMS & CONTROLS - home
• WATER FEEDER VALVE, HYDRONIC BOILER
• WATER FEEDER VALVE, STEAM

Suggested citation for this web page

SIGHT GLASS, STEAM BOILER FAQs-2 at InspectApedia.com - online encyclopedia of building & environmental inspection, testing, diagnosis, repair, & problem prevention advice.

Or see this

INDEX to RELATED ARTICLES: ARTICLE INDEX to STEAM BOILERS

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