boilermate 2000 faults

Hi, I have a problem with my boilermate 2000 system. I have hot water for most of the time, but no heating. The pumps are working as I've false fed them to prove it. I've followed the diagnostic check on the back of the door and it's telling me no sensor is faulty. There is a buzzing coming from the small black box on the PCB. Does anyone have any ideas, thanks

Well, you need to check that when the heating is on that there is a demand into the correct terminal on the electrical connection. Then is there any voltage to the pump? is the sensor ok?(fault codes don't always help) then after that it could be the ridiculously expensive and incredibly unreliable pcb that geldhill stuck to this heap of sh1te.
If the pcb has gone there's a chance that something else is taking it out. So worth doing a comprehensive electrical check of system before replacing it.

With Micky on this.

I have fixed quite afew for Gledhill locally and can say that the pcb is the worst one I have ever come across.

The temp[ sensors are also poor.

The pumps are shortened in life span because of the way the pcb modulates them.

Anything at all which fails generally takes the pcb with it.

The problems of the design stem from the rediculous ideal of controlling temperature to 0.1 dgrees C. Absolutely pointless.

If I owned one I would rip out the pcb and temp sensors and stick pipe stats and cylinder stats around the place and work out my own electro/mechanical control system with an acuracy of 5 degrees c for total reliability and isolation of components so one blowing doesn't take out another with it.

But you probably need a pcb.