Help identify this air vent, manual or automatic?

sixplex

So this guys was leaking, it's labelled RA-RICH N1-W. It is extremely old. Is this a manual or some sort of automatic vent? There is a screw at the top.

JUGHNE

I think I have seen something like this, it was considered automatic.
Vents air but when water gets to it, some material inside swells up and closes the port.
I just replaced with manual vent and operate as needed.

hot_rod

It may be a hydroscopic cap. Some are both manual and automatic. As @JUGHNE mentioned, they have a stack of cellulose fiber washers inside. When they are dry air expels. As soon as water hits they swell and shut off.

JUGHNE

The ones I came across were hiding inside of a convector.
They had obviously been leaking for some time.

The system I speak of had an old school "compression tank" and should not have any auto air eliminators anyway.

I put manual key vents on for start up purposes.

sixplex

It's exactly what it is, i cut the sucker open with a reciprocating saw. There is also this type in the same system labelled as "duo vent". They haven't worked for over a decade ca

JUGHNE

What type of expansion tank is on this system?
Something of this vintage may have the large hanging compression tank as mentioned above.

Pictures??

hot_rod

In reality those discs should be replaced about every 3 years.

Or turn the cap down and seal them off Use it as a manual vent only is probably how most hydroscopic vents are used, as not many are easy to identify. Usually when you see a tall cap like that, there is something going on besides just a sealing cap.

We actually sell quite a few of these. The Caleffi has a ball check, so the guts can be easily replaced without losing a drop of fluid.

retiredguy

Wow, I haven't seen this type of vent in years. I hated them and yes I replaced them with key vents. Since you guys have identified them to a TEE you must be older than I thought you were. HA HA