Ideal Vac Vent 822

dedminster

I live in a house built in the 30’s. There are two of these vents on a “T” that I want to replace. What would be the modern equivalent?
Thanks for your help.

phillipsjasona

What did you end up using?  I have the same vent and want to replace it. 

motoguy128

There is no equal needed because your system is no longer coal fired so it doesn’t need to drop into and hold a vacuum. Better to use more and faster main vents like a BigMouth and if needed a vacuum relief to stop whistling at the radiator vents (big mouths stay closed one hot) as the system shuts down and rapidly draws a vacuum.

https://www.supplyhouse.com/Barnes-Jones-BJ-3BM-3-4-Big-Mouth-Main-Air-Vent

That being said, they do make a Hoffman 76 vacuum vent. But it’s not a very fast vent. You’d Normally use it only on Certain vacuum specific 2 pipe system, most likely where there is a supplemental vacuum pump.

https://www.supplyhouse.com/Hoffman-401432-76-1-2-x-3-4-Straight-Main-Steam-Vacuum-Valve-11742000-p

clammy

If your systems is a vapor vacuum system I would think about installing a Hoffmann 76 the reason being that even though they vent slower the upside is they close so vacuum can form which shortens distribution time on start up when in vacuum . Another plus is they will help your system produce steam at lower temps . In my closing thought is that most vapor vacuum systems never see or have to vent much air and when switching to say above big mouth or any standard vent the system will be breathing and sucking in air on the off cycle . So when start up come round you will be waiting for the air to vent out of the mains Andy radiators . I know I’m kinda alone on this but if the boiler is properly sized for the edr and piped properly and clean . I feel it can still be usefully to keep it a vacuum systems as long as it holds a vacuum which indicates a nice and tight system ,if so why let it suck in air and increase potential for corrosion . Of course a vaporstat should be used and if gas and oversized then a 2 stage gas valve would be in order . It s really amazing when you run a vapor vacuum system that still operational and holding vacuum the distribution cannot be beating it’s quick and quite . I know that those 76 are not cheap but I always have one on the truck of course w a big mouth and gortons . Peace and good luck clammy

motoguy128

No need for a 76 unless 2 pipe or all the 1 pipe vents are vacuum vents.

FWIM, a big mouth will act like a temporary vacuum vent As it stays closed once hot until it cools off. I actually had to add a vacuum relief because they stay closed on shutdown.

PMJ

clammy said:

If your systems is a vapor vacuum system I would think about installing a Hoffmann 76 the reason being that even though they vent slower the upside is they close so vacuum can form which shortens distribution time on start up when in vacuum . Another plus is they will help your system produce steam at lower temps . In my closing thought is that most vapor vacuum systems never see or have to vent much air and when switching to say above big mouth or any standard vent the system will be breathing and sucking in air on the off cycle . So when start up come round you will be waiting for the air to vent out of the mains Andy radiators . I know I’m kinda alone on this but if the boiler is properly sized for the edr and piped properly and clean . I feel it can still be usefully to keep it a vacuum systems as long as it holds a vacuum which indicates a nice and tight system ,if so why let it suck in air and increase potential for corrosion . Of course a vaporstat should be used and if gas and oversized then a 2 stage gas valve would be in order . It s really amazing when you run a vapor vacuum system that still operational and holding vacuum the distribution cannot be beating it’s quick and quite . I know that those 76 are not cheap but I always have one on the truck of course w a big mouth and gortons . Peace and good luck clammy

Gee Clammy you are brave man saying stuff like that around here. Watch out or you may join me on the soon to be cancelled list. Independent thinking that doesn't follow the party line seems to have become a liability generally these days. When I was growing up it was clearly viewed as an asset and welcomed. Kept people more on their toes and forced to actually think about stuff - even stuff they thought they already knew all about. That's what I like about my steam project - always something new to be learned. The lab is right in my house and I can fuss around whenever I want. Life is good.

All the best, Peter

Steamhead

@phillipsjasona , I must have missed this when @dedminster started it. So I'll ask the standard question- how long are your steam mains, and what pipe size?

If you want to see what @PMJ is talking about, go here:

https://forum.heatinghelp.com/discussion/181044/goin-up-the-country-milvaco-vapor-megasteam-rescue

Joe_Dunham

You can install a 1/2" or 3/4' swing check in line with any vent you want and make it hold a vacuum. Just put it horizontally