potterton performa 24 fault?

[1983mk]

hi all, new to this site.
I have a problem with my combi boiler, its a potterton performa 24.
I had slight hot water at taps and no central heating the other day. I removed the H/exchanger and descaled it. re fitted it and i now have lovely h/w but still dont have Central heating. any ideas?
I have noticed that there is a 3 port valve to left hand side of boiler and if i am correct there is a switch that seems to should make contact with a pin from the 3 port valve however it looks stuck? do i require a new 3 port valve or just the inside part?
many thanks

 

[1983mk]

big brass one? is that the one on the front to the left hand side. looks like it comes out of the valve and should 'make with a switch'? that switch is that switch for heating?

 

[Billy Bob Bob]

if your getting dhw lots can be ruled out,things that would make the heating play up
1. thermistor
2.time clock(if fitted)
3.roomstat (if fitted)
4. blocked return filter
i think we can eliminate the pump as the boiler would be locking out on dhw,is there any air in the rads?

 

[1983mk]

no air as been bleed. no roomstat fitted.
first had no h/w or c/h then cleaned out h/e and got h/w. then put heating on and rads started to get hot. but only upstairs? if i put a screw driver against the switch the the spindle is ment to touch would that make heating come on??

 

[Billy Bob Bob]

are you talking about the switch on the back of the diverter valve or the front?

 

[1983mk]

if that cover off boiler its the front - left hand side

 

[1983mk]

if take cover off boiler its the front - left hand side

sorry spelling aint great lol

 

[Billy Bob Bob]

thats for the hotwater no bearing on heating open a hot tap it should move