Vent at end of main

HeatingHelp

This discussion was created from comments split from: main vent on return piping.

Laars66

what type of vent should I put at the end of a return line ?a gorton? What size?

Jamie Hall

What kind of "return" line? Some need no vent at all… some need a full size main vent…

alanm

thanks….it is a return line /cast iron…and right now there is a valve…. see at top upper right…valve is "green".

thanks alan

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ethicalpaul

The recommended size depends on the size and length of your main. Your current one is a Hoffman which I think makes a terrible main vent in terms of bang for buck.

One similar to that capacity is a Gorton #1 but depending on your main a Gorton #2 would be better. See this article by Gerry Gill and Steve Pajek

What size and how long is that main?

You seem to have a second main as well. Does that one have a vent?

alanm

thanks…..i think a unique system!…….one run handles all radiators except 3… that other run just handles 3 radiators (one on the first floor, one on the 2nd and one on the 3rd). the run that handles just 3 radiators does not have any return/valve. the main run about 85'….and i attached another photo…Hoffman 75 vent at the end of the main on that run. any insight will help! thanks

vent 1.jpg

vent 2.jpg

vent3.jpg

delcrossv

Both returns should have vents. for the short one with only 3 rads, the Hoffman 75 would work well on that. There's a convenient union on that one to place a tee with a riser for another vent.

The other main, that runs everything else, should have a larger vent.(which should also be on a riser)

alanm

ok….cant picture where to put that vent on the short one….piping from boiler for that short run….pipe heads off to the first floor radiator and then it continued to the 2nd/3rd floor ….see diagram…where would i put the vent?

thanks

delcrossv

Diagram?

If it's just one outgoing pipe that doesn't come back, it's counterflow . If it just feeds the riser, I'd put a vent at the top of the riser before the 3rd floor rad. That way you can make sure you're not overheating the rad while getting the air out of the pipe.

alanm

ok….is that why those 3 radiators dont seem to get hot unless i have temperature up high….and then it drops off when heat is on…is that because of no vent?

ethicalpaul

Yes that is a likely cause. All the air in the main pipe has to be expelled through the radiator vents which can take some time

delcrossv

Yep. and you don't want a big vent on the top radiator because that room will roast. Hence the two vents.

delcrossv

And get some insulation on those copper pipes. 😉

alanm

thanks…anything special…what type of insulation should i use? besides making my basement cooler (!)….what does that do to the rest of the system/radiators? thanks again Alan

delcrossv

I inch paper backed fiberglass pipe insulation. The more you insulate the faster steam gets to where you want it (instead of heating the basement)