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. .
--
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

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. .

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. .

I did mine differently...

On the engine expansion tank (now no longer the high point in the
system) I installed a 14 lb radiator cap, replacing the 7 lb cap. Then
at the high point in the system (approximately...) I installed a small
expansion tank (from Summit Racing, but could have been from anywhere),
and put the 7 lb cap on it. Air collects in the tank (a little is
necessary to accommodate the expansion when the coolant gets hot), and
the engine expansion tank is now full to the brim.

This cost more than your approach, but it doesn't have any moving parts...

bob



Glenn Ashmore wrote:
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.

Well, it is brass with a high temp polyethylene float. It has to be mounted
close to vertical to open. I was worried that when the engine cooled and
the pressure dropped it would act as an anti-siphon valve and let air back
into the system but after playing with it that does not seem to be a
problem. I do believe however that after the system is purged it would be
a good idea to close the outlet valve just in case and just open it when I
am changing out the coolant.

--
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

"Glenn Ashmore" wrote in message
news:VANBf.13635$Dh.2158@dukeread04...
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. .

Glenn, when the system cools, air will re-enter the system thru the
radiator cap - it is designed to do that

Glenn Ashmore wrote:
Well, it is brass with a high temp polyethylene float. It has to be mounted
close to vertical to open. I was worried that when the engine cooled and
the pressure dropped it would act as an anti-siphon valve and let air back
into the system but after playing with it that does not seem to be a
problem. I do believe however that after the system is purged it would be
a good idea to close the outlet valve just in case and just open it when I
am changing out the coolant.

"RW Salnick" wrote in message
...
Glenn, when the system cools, air will re-enter the system thru the
radiator cap - it is designed to do that

The way I read the shop manual it won't if the overflow tank is set up
right. It will suck the coolant back in that was pushed out as the engine
heated up.

--
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

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.

Thanks for the info, Glenn... I'm going to invest in a few
of these myself!

DSK