Boiler water loss during off season

geemalar

Woke up to some cooler temps this morning so I decided to turn on the heat this morning. Prior to turning it on I went and checked my water level and I noticed it had dropped about 5 inches in the sight glass from the normal level since sitting unused since about April? I don’t recall that ever happening before, or at least not that much of a drop. I added the water (manual feed only) and ran the system. Everything seemed to work fine.
How concerning is it having dropped that much over the past 6 months?

While on the subject, I had plans to flush the boiler this year as it hasn’t been flushed in quite some time. Should I add any cleaning product to the system in order to help clean out the boiler? Thanks for any assistance………

Steamhead

There's a leak somewhere. Do any of your return lines run underground?

Jamie Hall

and the leak has to be in a return or in the boiler itself. Critical question: was the water level below the Hartford Loop?

geemalar

None of the return lines run underground. The water level was right about at the same level that the Hartford loop returns to the boiler line. The return line is behind the vertical pipe, you can faintly see it in the second picture directly below the 90 degree elbow

mattmia2

is the return overhead until it gets to the boiler?

geemalar

The return starts out about 4 feet high at the opposite corner of my basement. It has a slight downward angle as it works its way back along 2 walls to about 5 feet from the boiler. From there it drops 90 degrees down to about 6 inches off the floor. Proceeds to run back to the Hartford loop line seen in the picture. Turns 90 degrees back up and the makes another 90 degree turn that’s shown in the second picture.

109A_5

The water level should have stayed where it was in the Spring, assuming the boiler is not used to also heat DHW (Domestic Hot Water).

It may be a coincidence that the water line stopped at the Hartford loop level. Even so I would inspect (very carefully with adequate lighting) under the boiler, the bottom of the boiler's block and the short wet return for any evidence of leaking, like any disturbed dust where water was dripping or any corrosion on any of the metal parts and piping.