main vent #40

alanm

I am having some water in radiators, some radiators not heating (pitched and new vent)---all after a new boiler and skimming with chemicals! anyway, as I try and figure out problem, how do you know if the main Hoffman 40 vent is bad? it is about 15 years old...no water stains around vent.....thanks

nicholas bonham-carter

The way to test a main vent would be to:
Turn the boiler off,
Remove the vent, and see if you can blow through it, while holding it vertical.
If it is plugged, then replace it with a Big Mouth vent.
What chemicals were used in the final cleaning? Skimming properly does not use chemicals, which will sink to the bottom, and adversely affect heat transfer. They may also cause unstable boiling.
There should be a skimming port installed, (check the installation manual).
Post some pictures of your near boiler piping for more advice.—NBC

alanm

not sure of chemicals, but after water was in system and coming out of radiators, I had them come back-- they since re-skimmed 2 more times! but still water in radiators.....any suggestions...see photos of boiler

Dave0176

You should probably get that copper replaced with steel. Copper is not good above the water line.

Also the No40 vent is really waaay too small to vent a steam main, it only vents about .04 cfm you need something like a Gorton No2 that vents about 1.1 cfm or a Barnes & Jones Big Mouth that vents around 3 cfm.