vaillant combi problem

[zoe8773]

when i turn on my central heating the temperature shoots up really quickly then turns off then keeps turning on for almost a minute then turns off. only 1 radiator gets hot.
if i turn on the hot water tap the water does not get hot it gets tepid, but central heating starts to get hot ?
can anyone help please/

 

[mrgas]

Without knowing which model boiler you have , my money would be a fault diverter valve

 

[gas4you]

Following on from above, I would expect more than 1 rad to get hot if the DV was stuck on ch or mid position.

Check your pump is working ok.

We need model of Vaillant though.

 

[zoe8773]

boiler is a vaillant ecomax 824/2 e

 

[micky p]

sounding more like the diverter. They had a few problems with the divert valves on that model. Could be a blockage tho.

 

[zoe8773]

can diverter be repaired or does it have to be a new one?