sight glass issue

rayians

Hello all,

I recently acquired a home with an oil fired steam heat boiler/furnace. The boiler has a sight glass on it. I have never had to deal with one of those before.

To make a long story short, the house is vacant so I shut the furnace off to save some heating oil. I walked past it a few days later and noticed I could not see the water level in the sight glass. I was assuming it was empty. I ran water into it for a good minute or so and to my eye, the level didn't change. I checked it the next day, and the top of the sight glass was leaking. Apparently, shutting the furnace down raised the level in the sight glass and did not lower it. Therefore it most likely didn't need water, now I've apparently severely overfilled it.

A few questions on this, first of all, if I tried to turn the furnace back on, would I cause any damage or create a dangerous situation? Also, how can I drain some of the water out? How do I know what a proper level is if the level changes when the boiler is dormant?

Any advice whatsoever would be tremendously appreciated. Thank you all in advance!

delcrossv

There will be a drain valve near the bottom or lower 3rd of the boiler. Usually lookls like a hose connection.

You can drain until you see the waterline in the middle of the glass. Thats the normal operating level.

Overfilling seldom causes safety issues. You should be fine to start the boiler after adjusting the water level.

Probably good to get someone to look over your system before next fall.

Lastly, get the book " We've got Steam Heat" available on this site. Very helpful for a new owner of a Steam system.

rayians

Would I be correct that the water level in the sight glass raised simply due to my shutting the boiler off and letting the system cool down overnight?

ethicalpaul

No.

delcrossv

Not usually. With the boiler cold, drain until the waterline is in the middle of the glass and then operate the system.

Keep an eye on what the level does and report back.

Do you have an automatic water feeder?

109A_5

The water level should not rise excessively by its self. The water feed system automatic or manual may have a slow leak overfilling the boiler.

If you have an automatic feeder it should periodically raise the level to maintain a safe working water level, but not over filling it.

You really need to figure out if it was under or over filled. With the boiler off and cool, drain it than refill it so you know how the sight glass looks. Once at the proper level run it at least once to help push out the excessive oxygen to minimize corrosion.

EdTheHeaterMan

Since your water level is moving slowly in and out of the glass, there is most likely a blockage in the connection to the boiler. That is common on steam boilers, especially when there is no maintenance performed for some time. There are other locations that can get blocked or partially plugged including the piping that feeds the high limit pressure control (usually a Honeywell Pressure-trol), and the pipes that connect the pressure gauge to the boiler.

The book https://www.heatinghelp.com/store/detail/we-got-steam-heat-a-homeowners-guide-to-peaceful-coexistence/ is a must read instruction manual for the new homeowner that has never had a steam heating system before.

As far as turning off the electricity to the boiler is concerned, that does not add any water to the system and would not cause the water level to go up the gauge glass.

rayians

I did find the drain valve and was able to drain it down to the point that it is in the middle of the sight glass. I was still a little skeptical whether I should attempt to fire it up or not, but apparently that would be advisable at this point. I do not have an automatic feeder, it is a manual ball valve. I do have a low water cutoff so I am assuming there isn't much to worry about at this point. I will report back once I fire it back up.

ethicalpaul

See if over time the water level goes up, indicating the manual ball valve is leaking by. But I would bet that someone just overfilled it at some point.

Yes you can fire it up.

For what it's worth, i don't like automatic feeders. You can definitely be fine without one.

mattmia2

Does the boiler also make domestic hot water?

rayians

I only ran it for 10 minutes just to see if I would have some sort of obvious problem. No issues at all to this point. I'll be curious to see if after a day or two the level creeps back up again. The boiler is also the hot water heater for the house.

mattmia2

If the tankless coil or coil in the indirect, whichever it uses for DHW, is leaking, that will add water to the boiler.

ethicalpaul

https://forum.heatinghelp.com/discussion/comment/1850659#Comment_1850659

Good to know!

rayians

As luck would have it, I took a look at it today and the sight glass was full again. Apparently I have some sort of a leak. I shut off the ball valves for the hot water to see if that changes anything.

Intplm.

https://forum.heatinghelp.com/discussion/comment/1850806#Comment_1850806

1-Manual valve is leaking by

2-Auto-feeder is leaking by

3-Domestic hot water coil is leaking into the boiler.

I'll bet its number three, and hopefully not a combination of the three. 🙄

rayians

There is no auto feeder. My untrained guess is #3 as well. Since I've shut off the ball valves into and out of the coil, If the level does not rise tomorrow, would my guess be correct that the coil is the likely culprit? How else can I be sure?

delcrossv

https://forum.heatinghelp.com/discussion/comment/1850810#Comment_1850810

That would be pretty definitive.

mattmia2

Note that there should be a relief valve on the DHW coil, especially if there is a valve on the outlet. In fact I would leave the valve on the outlet open and leave a hot water tap open somewhere or at least let some air in to the dhw system or you might have a leak in the coil that wasn't there before once the water in it heats with it valved off.

EBEBRATT-Ed

Close the cold water inlet to the coil and leave the hot water valve open to the coil. If you don't have a pressure relief valve on the coil you will have a hole in the coil if you run the boiler with both valves closed