I will go by Grainger this morning to pick one up. They are only about $7.
It is made by Watts Regulator so it is probably red brass but in a normal
engine room environment on the closed side of the cooling system it should
be OK. I will dissect it and report back.

--
Glenn Ashmore

I'm building a 45' cutter in strip/composite. Watch my progress (or lack
there of) at: http://www.rutuonline.com
Shameless Commercial Division: http://www.spade-anchor-us.com

"RW Salnick" wrote in message
...
I would sure be interested in how this device works out, Glenn. Is it made
of material suitable for marine service (that is, no mild steel, etc?

bob

Glenn Ashmore wrote:
OK. I have hung the water heater hose from the engine room ceiling. I am
still worried about trapped air but just discovered Grainger part #
4A820. It is a float type automatic air vent made specifically for
removing air from hot water heating systems. It vents air until if fills
with water. Says it is glycol compatible, 240F max working temperature
and works to 150 PSI. The vent can be sealed with a little screw so once
the system is purged I can seal it off and it is only 3" high. Looks
like the perfect solution. .