In a message dated 6/10/05 8:52:27 AM, rrecardo@webtv.net writes:

<< The rear heater won't do much without the fan on. Correct you are.>>

Obviously.

<<But crank that valve open on the front heater at speed and see what
happens.>>

Why?  I wasn't talking about a parallel heat exchanger which is sitting in a
forced air draught of outside make-up air.

<<Your vehicle has some problems if the temp rises when you just open the
rear valve. >>

I think the problem is that you are not considering the consequences of the
mass flow through two elements of vastly different rates of heat transfer under
the different conditions.

Geek Patrol, quick, send in the Thermo Squad.

George