My vents are whistling

Steamhead (in transit)

if the vents whistle after the boiler shuts off, they're sucking air in. Rapidly condensing steam in bare pipes can cause this.

Steve Garson

My vents are whistling

My new SGO-4 boiler is now running daily.

The vents on my radiators are whistling, which they never did before. But they get hot much faster than the old boiler.

I notice that the whistling starts when the steam pressure hits 0.3 psi and gets louder until the cut-off at 1.5 psi.

I also notice that the watch glass has occasional drops of water dripping down from the top when the water boils.

The piping seems correct, with a 27-inch distance from the water line to the bottom of the header. All is done per the WM specs. The mains are well vented with per Steamhead's recommendations.

Can anyone advise me what is going on and how to resolve this?

Steamhead (in transit)

Probably needs skimming

Water carrying over the top of the sight glass usually means it's dirty or has oil laying on top of it. If you're only getting a few drops it may be borderline, but should still be cleaned.

Steve Garson

Should I just skim for an hour or so, or do I need to add TSP?

patrick linhardt

I agree

Sounds like the boiler needs a good cleaning, by skimming or chemical treatment. The space above the waterline in the glass, like the inside of the boiler itself, should be full of dry steam, without droplets of water. Oil on the waterline creates excess surface tension which prevents the steam bubbles from cleanly releasing from the water.

A second possibility, and this could go with the whistling vents, is burner over-fire or boiler over-sizing. How was the burner set-up and the boiler sized?

Best regards, Pat

Steve Garson

The boiler is sized properly and is using the burner and nozzle that shipped with the WM SGO-4. My heating system has 450 sq ft.

Steve Garson

I just spend a couple of hours cleaning my boiler: TSP at 180* for two hours and then continuous flushing from the drain while refilling at the same rate. Then I completely drained it and refilled to the water line.

First steam cycle had no water dripping down the top of the watch glass. My vents did not whistle on the steam cycle. BUT, two vents hissed after the pressure dropped. These are new sounds since getting the new boiler. The vents are new.

What shall I do now?

Steve Garson_2

The radiator is question has twenty feet of pipe in above a finished ceiling. The pipe is not insulated. So I guess there isn't much I can do. All the assessable pipe are well insulated.

I must thank you for all your advice over the past year. I've become a steam fanatic. This weekend I am changing a return pipe that isn't pitched adequately, for no other reason than it should be pitched more. It's been like that for 70 years:)