diverter valve ? or thermostat ?

[macelvis]

hi there just a couple of days ago i noticed my radiator hadnt heated up in the morning .after a bit of snooping about i think ive come to the conclution its either my diverter valve or thermostat
when i turn on programmer for hot water the boiler fires up but when i do it for c/h it doesnt but if i slide the lever on my honeywell 3 position divertor valve to open it fires up but goes of again . im not sure if its the valve thats faulty or maybe if the thermostat in my hall is faulty . boiler works perfect when only using it to heat water . can anyone help
thanks alistair

 

[londonboy]

I would say it could be the microswitch in the 3 port, but if you manually move the lever and it fires up then this is probably ok. So maybe the room stat? Might be worth taking the roomstat off and linking the connections in a connector block, to bypass the stat and see wether it is the 3 port. Roomstats barely go wrong btw.

 

[macelvis]

thanks londonboy that was a really quick reply i will try it to see
cheers alistair

 

[macelvis]

theres 3 wires in thermostat so will i divid them up on the block and try switching central heating on programmer

 

[namsag]

usually its the valve
90% of the time it is the valve motor that has gone and you can get away with changing it the other 10% its the little board in the valve that has gone and you will need a new head or complete valve

 

[londonboy]

Yes the motor completely skipped my mind, because the valve fired the boiler on manual I wrongly assumed it would be ok! Sorry will pay attention more from now on