Thanks for your reply!
I have checked the motor, it works as it should and moves correctly on demand.
Could the P-HEX, if blocked cause excessive pressure from the pump causing the seating on the spindle of the diverter valve to lift and cause the CH flow pipe to heat-up?
Can anyone confirm...
Hope someone can help?
I was called out to this breakdown today (just started boiler breakdowns after 12 years of installing)!
Symptoms... CH flow pipe heats when any hot water outlet is opened.
Only 1 hot water outlet (kitchen sink, closest to boiler) operates at a constant temperature...