Steam Main line Vent Question _ beating a dead horse

MaxGNaidu

So I have read few artricles on here and official documentations and everyone on here seems to be on the same page, either go with a Groton No 2 (long line) or No 1 (Short Line) vents or one of Hoffman 401413/16/29/32/34/37 depending on the cofig/setup of the system. but apart from this info what are we as consumers should be aware of ? how big the vent port should be ? I am looking for specs, which seems to be missing from the literature out there. Emerson Swan was kind enough to inlcude the specs of their vents in their brochure and looks like their #77 model main vent is the one with the biggest vent port with a size of 1/8inch with a neat price tag of 100$, all the hoffman main vents are a standard between 150$ to 240$. groton no1 and 2 are 110 and 60. so seems like all the main vents are priced above 100$. but the ones in homedepot and Lowes branded Durst A883 for 12 or 15$ also seem to have the same fitting size as a main vent but the hole is literally puny. Lowes even goes and brands then as a main vent when clearly they are not. it clearly says on the package that its a radiator vent. just venting.. hope someone who needs this info finds this article and it makes their life easy.

Mad Dog_2

Gerry Gill and Steamhead could tell ya. Mad Dog

Jamie Hall

This handy dandy publication: https://heatinghelp.com/assets/documents/Balancing-Steam-Systems-Using-a-Vent-Capacity-Chart-1.pdf has a table at the end which lists the actual measured flow capacity at various pressures of a wide range of vents (thanks, @gerry gill !).

For the purposes of this question, it isn't just the size of the visible opening -- nor the size of the attaching thread -- which is important. The way the innards are built is critical.

Mad Dog_2

There you go! Thanks Jamie. Mad Dog 🐕 

ethicalpaul

> groton no1 and 2 are 110 and 60

I think you have those backwards, but that's OK I knew what you meant.

But where are you seeing those prices?

The #1 is currently $36 (up recently from about $30): https://www.supplyhouse.com/Gorton-G14-Gorton-No-1-3-4-x-1-2-Air-Eliminator-Main-Vent-Valve-3522000-p

The #2 is about your quoted price, I see it $115 on supplyhouse

I used to recommend the nearly identical maid o mist #1 because it used to be only $18 but now it's $28 on supplyhouse.

Main venting is great, but don't throw money away. Time how long your system takes to fill the main with steam with an open pipe at the main vent attachment point, and then throw a #1 on there and see how much longer it takes. It won't be very much different I bet.

MaxGNaidu

oops, looks like I got my pricing mixed up, yes, No 1 is the cheaper and smaller one and No.2 is the big daddy. infact I went ahead and bought the no.2 to piece of mind thing. will install over a weekend.

ethicalpaul

You should be in good shape, good luck!