Is there such thing as too much air venting?

Bcos17

I'm in the middle of re-piping my Williamson 66k BTU hot water boiler. The system previously had no air elimination and that's one of the things I'm trying to fix. I have purchased and will be installing a 1-1/4" Caleffi Discal air separator. My question is about the small pipe circled in red in the attached photo. I believe this is supposed to be the location of one of those small can air vents. Something like this:

https://www.supplyhouse.com/Caleffi-502243A-1-2-High-Capacity-Auto-Air-Vent

My question is, if I am installing a large air separator, do I also need to install one of these smaller vents on this pipe? or should I just leave it capped? If I need one, is there one model or brand that's better than the others?

Mustangman

That nipple and cap simply plug a hole in cast iron. If you were going to use a large compression tank you typically see in the basement ceiling, you would have used that 3/4 tap to connect the boiler directly to the compression tank. There is a baffle in the boiler casting which diverted air from the boiler to that 3/4 tap, right up to the compression tank. No worries on the cap

Bcos17

I'm planning on mounting the expansion tank (Amtrol ex-30) directly below the air separator. Does it benefit me to also install a small air vent on this pipe?

Alan (California Radiant) Forbes

Your new air separator will take care of any air in your system as it passes by. Why would you want to install an additional air vent?

EdTheHeaterMan

Bcos17 said:

I'm planning on mounting the expansion tank (Amtrol ex-30) directly below the air separator. Does it benefit me to also install a small air vent on this pipe?

The benefit will be that it will start to leak at some point and perhaps you can make some money on a future service call in a couple of years. Other than that, I would leave the cap in place.

Disclaimer: click on spoiler

I do not recommend putting stuff in a heating system that will fail in short order in order to make $$ on future service calls. That was a Joke for April Fool Day

hot_rod

One air purger or separator at the boiler us adequate 

some times auto or manual cents are added at high points in the system 

Bcos17

Thanks for all the answers! I guess I don't need it since I'll have an air separator. I was only going to add it if it would help or I needed it.