[DeTomaso] electric heater valve - UPDATE INFO

[Larry Finch]

 All,

The OPEN/CLOSED plastic body 12 VDC valve I referenced yesterday had a stated
maximum temp rating of 195 F. This caused us a bit of concern.

I have spoken with the seller, who is also the company owner. I gathered he is an engineer,
and actually knows his wares rather than being just a vendor of items he knows nothing about.
I learned this valve also has other shortcomings, but have in turn found another valve offered 
by this seller that is properly suited for our heater coolant shut-off duties.

The plastic valve was only design-rated at 176F. The seller, like some of us, reasoned
the valve's component materials were easily suited for a higher rating, and he thus
listed the 195F rating. Soooo, the over-designed fudge factor has already been taken.
Over time, the seller feels the elasticity properties of the diaphragm might degrade and
diminish sealing properties. Additionally, that valve's opening motion is dependent on the
pressure of the coolant. As our coolant system operates around 14-18 psi, the pressure
is not enough to guarantee full opening.

This valve however should perform the task without any reservations:

http://tinyurl.com/high-temp-valve

It is $20 more, but is a brass housing with a Viton diaphragm; rated at 266F. In addition,
this valve is suitable for gravity feed uses, meaning the open position is spring-assisted;
the low system pressure in our cars is not a concern.

The seller feels while this valve is a 1/2" size, it is better suited for our 5/8" hoses than
a 3/4" size would be. It comes with 1/2" FNPT threads. The use of two 1/2"MNPT x 5/8" barbed fittings
would easily adapt it for our use.

Full specs are available by using the links in the auction.

Larry