Baxi 105e CH problem

[geordiebuilder]

Hello Gas folk,
I have a problem with the above mentioned boiler in that my DHW is functioning normally but my CH is not.
None of the usual fault neons are flashing, pressure is normal and I've checked that power is getting through the selector switch to the PCB.
That is the limit of my knowledge, I'm a builder you see.
If anyone can shed any light on this problem I would greatly appreciate it.
Many thanks.

 

[namsag]

What other controls do you have eg roomstat ,built in clock, seperate clock etc

 

[geordiebuilder]

Hi,
I am only using the potentiometer controls on the boiler no other controls, not even a mechanical timer.
Cheers.

 

[bengasman]

no timer and no roomstat equals cowboy job. 90 percent chance the system is dirty which means almost surely the diverter is stuffed on this model, they are prone to faults due to corrosion and limescale