water low in steam boiler

We just bought an old house with one pipe steam radiators. We have a Burnham boiler circa 1991. About 3 weeks ago, I went over the system with the heating technician. At the time, the water level in the sight glass was about n inch from the top.

Today, I noticed the thermostat was calling for heat, but the boiler was off. I noticed also that there was only an inch of water in the sight glass. As soon as I added water, the boiler came on. What would cause it to drop like that?

There are no leaks near the boiler, and I replaced most of the vents at the radiators.

Thank you
Dave

 

The only thing that comes to my mind is the water is trapped in incorrectly pitched pipes. After you refilled the boiler.... how did the heat work ?

 

It worked great after I filled it.

 

Do you have an auto fill? If not the boiler will use water and need to be filled at times.

 

Are any of the valves on the radiators only partially open, they should all be fully open, all the time. Do you get any hammering in the steam lines when the boiler comes on? What is the model number of the old and new steam vents? When the service tech was there did he make any adjustments to the boiler or the gas input? Did he take apart all the water line devices to make sure that they were cleaned out, check the pigtail syphons to make sure that they were not plugged, and did he check to make sure that the automatic feed unit worked correctly? If the boiler had been off for an extended period of time, maybe 2-3 hours, the sight glass should have been full, to near the top. Do any of the return lines run under the floor? I would check closely for water leaks in any and all piping especially any piping that runs under ground, or any piping that is hidden from direct sight. You probably have a leak somewhere or you have overlooked something.

 

Auto fill is the way to go on those things.

 

All valves are open. We do not have an auto fill. I opened the valve manually, and it filled the boiler. None of the radiators make hammering sounds. Just the typical metal expanding. I did find one radiator that was dripping a bit from the connection near the valve and tightened it. I’m not sure how often a steam system should need water. I would think it would be rarely. The old vents look like Hoffman. The new ones are Vent-rite. The tech did not take any piping apart. The boiler is oil fired.

 

I know that you don't have auto fill. I was in a house built in the 20s that didn't have it either & I had it installed. It was well worth $500. You would think that it rarely needs water after you 'fix' everything but that wasn't the case.

 

Thanks, I’ll look into it. Any brand you’d recommend?

 

I accepted whatever they brought.

 

Boiler is running now. Is it normal for water in sight glass to pulsate rapidly up and down a couple inches as it runs?

 

If the water fluctuates a lot that means the boiler is dirty and needs to be skimmed.. Look it up....