>> Static pressure of liquid being pumped is 40-80psi above atmosphere 
>> (ie: the reservoir is under city water pressure). Note that the pump 
>> is recirculating through the reservoir, so it only sees a small head.

Could you not set up a convection circuit between the chambers ? Perhaps 
using a small auxiliary heater in the up-duct ?

Peter
-- 
http://www.piclist.com PIC/SX FAQ & list archive
View/change your membership options at
http://mailman.mit.edu/mailman/listinfo/piclist