Hydraulic separator question

CBRob

I have seen the light and can appreciate the simplicity of a hydraulic separator from caleefi.
I was wondering what this little fitting was at the top of the separator. Kind of looks like a check valve? It's where the air vent goes.

There's also a brass screw on the front that is an opening for an accessory port I think.
Is that meant to put pressure gauges and temp gauges in?

CBRob

This fitting 

hot_rod

That is a service check. Screw a 1/2" air vent into it. Then you can remove the vent for service without draining pressure.

CBRob

Is there a check valve in the thermowell on the front?

EBEBRATT-Ed

If it is a thermowell why would you need a check valve?

GGross

I believe they are just plugged and if you want to use the well for a sensor you buy one one of these

CBRob

Can you simply thread in a pressure / temperature gauge into that thermo well?

GGross

I think its a straight thread not standard NPT. Although between you and me, and definitely do not tell @hot_rod. I saw a guy pipe his expansion tank off that well port before, and it still hasn't leaked yet.

hot_rod

I have heard of people, like myself, wrapping a number of turns of teflon tape to seal a male NPT into a female BSP thread.

But you cannot go the opposite BSP male into NPT female. Easily

Check is for the top port where the air vent goes.