Originally Posted by BritCit_Juve
This is one of IMIs electronic units.
On the PCB are two potentiometers, one marked set temp and the other marked min speed. The set temp should be set to maintain around 270psi which is around the 10to location while the min speed should be around 10past. The fan motor is a single speed item but is speed controlled by phase chopping the neutral. There is also a pair of pins marked JP6 which when linked will cause the unit to run the fan flat out. what effect does this have?
The unit in question is I think a DCUE ducted unit so its possible the discharge duct is blocked. This could result in the high ampages you were reading and the motor overheating.
As the unit has been run with the electrics open then the intake grille can be discounted although it should also be checked