why no ch when i have hot water

[clayforth19]

Hi
I have a potterton ch system the hot water is fine but i have problems with ch not coming on as programmed

if i tinker with thermostat on cylinder i sometimes get ch working

or sometimes if i use manual over-ride on 3 port valve i get ch working

if i try and get system to work normally the 3 port valve makes a racket as though its trying to do something

thermostat in living room seems to be quite high as well (30 to 35) to start ch system

any help please

ps coal fired systems were a lot more user friendly ,but mucky

 

[kevplumb]

by the sound of it the 3 port valve or the motor or both are u/s

 

[clayforth19]

by the sound of it the 3 port valve or the motor or both are u/s

 

[kevplumb]

if its just the motor its fairly straightforward
if its the valve its usually a drain down