Miele G646 SC Plus: no heater d/w

[S1MON]

Miele G646 SC Plus

26/63472653

Looked at the above m/c, the fault no heat. Heater circuit all ok, cir pump running and activating the heater pressure switch.

There was 240v at the heater relay bottom left but nothing coming out. I bypassed relay and got heat.

Couple of questions, one does the 3rd connection on the relay link back to the pcb, and two have many people changed this relay as this is a relatively cheap product for a miele spare part and found this to resolve the problem or will the pcb also need updating. I was unable to check to pcb itself as the customer was off on a school run and I ran out of time.

Thanks Simon

[jeremy]

Re: Miele G646 SC Plus: no heater d/w

there will be a permanent 240v to the relay contacts, pcb energises the coil in the relay to close the contacts. if you are getting 240 at the coil and the contacts arent closing then the relay is goosed. Most common issue is heater pressure switch, either not enough pressure from recirc, ie its blocked or restricted in some way or the pressure switch is faulty. if all this is working and also the toc in the heater unit is ok and you have ruled out a wiring fault then last stop is pcb (ouch). btw EVERY miele has a wiring diagram usually tucked in behind the pcb on these i think.

[S1MON]

Re: Miele G646 SC Plus: no heater d/w

Excellent, I bypassed the relay and we were in business. I didnt check the feed from the pcb, as I thought this was 12v? Heater pressure switch is fine, checked that. Doubt the customer will want to pay out for a pcb!!

Wiring diagram was missing shame

[jeremy]

Re: Miele G646 SC Plus: no heater d/w

yeah on that one is 12v i think (going from memory) , earleir models was 240v, check the loom in the door, even though they are pretty well robust i have had wires broken there. fyi the heater relay has a perm 240v from the terminal block (on most of them) its the only component not isolated by the on/off switch. i will see if i have the circuit diagram if you wish ?

[S1MON]

Re: Miele G646 SC Plus: no heater d/w

Ok thanks I’ll check the loom

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