all that and check for air in water side of both evap and cond. 2 sensors and it is still off by 7 deg?? purge hasnt ran in a year?? not sure on the ch530 platform but the UCP2 would lock out purge if excess mins excedded in 24 hours, the chiller on the other hand would dance alll nite.
jump out the start contacts, clip a volt meter on the pair of wires (removed from term. strip) set up min/max on volt meter and see what is going on with the signal. or is machine vibrating so bad a relay is bouncing??
800 GPM?? is that a 3 pass or 2 pass evap? 800 too low for 2 pass