De Dietrich de DVY640JU1 – heater problems

This dishwasher baffles me, the owner says it does dry or get hot. I checked the flow thru heater which is fine.

I used the clamp meter on the Dow whilst running through the program, on the auto program, the heater ran for 4 minutes and the water temperature is 26 degrees when it should have been at least 55degrees.

I changed the program over to quick wash a 15 mins cycle but it lasted 10 mins with heater running for 2 mins.

Would that be thermostat issue, dodgy heater or dodgy pcb?

Cheers Matt