Gloworm CXI30 hot tap heating c/h pipe

[Niscars]

When I turn on my hot tap I notice that in addition to hot water at the tap the furthest left hand pipe on the boiler (c/h flow) also gets hot. Hotter than the tap pipe.
This sometimes actually heats the flat up when the thermostat is not calling for heat.
Anybody got any ideas please?

 

[AGAS]

replace the diverter valve

 

[ReganAndCarter]

You can get a repair kit. It's not too difficult, but any doubts and it would be better to get an engineer in.

 

[AGAS]

You can get a repair kit. It's not too difficult, but any doubts and it would be better to get an engineer in.

why ??

 

[ReganAndCarter]

Why what?