Don't like the idea of using a factory  controller tho..  Building a tail
dragger.  Things could get awful  hot on starting and shutting down without
water moving through it.  Thinking along the lines of having a manual
controller for a soft start and to keep temps where I want them. There would
be a single pole solid switch for back up if the controller went south.

Barny
MGDQ Super Rebel 20bt
-----------------------------------

The Davies Craig controller says it regulates the voltage from 3 to 12 V.
I'm assuming that they figure 3V will give enough flow to stop any localized
overheating, but I don't think it would be safe to assume that for every
situation.  Heck, I don't even know for sure that the pump will run at 3V.
Todd, Leon ???

My point is that there should be a permanent, minimum voltage on the pump
that will maintain some flow.  Having a backup switch is nice for full flow
if the controller failed, but I bet your engine would be toast in short
order if the flow ever stopped completely during high power output.  Even if
I used the controller, I'd probably provide a minimum "safety" voltage to
the pump, independent of the controller.

I noticed in the link that Perry gave, the guy is now planning to do what I
mentioned last night.  He's keeping a minimum voltage (half) on the pump at
all times, and using a temp switch to bring in full power when needed.

Rusty
Turbo 13B powered RV-3... Be Afraid :-)
1993 RX-7 R1... Stock (for now)