Worcester Highflow 400 - cutting out on CH cycle

[Keith D]

Hi. My Highflow 400 is cutting out when there is demand for CH.

The boiler kicks in initially when there is demand for CH, and the outlet pipe gets hot, however the return pipe remains cold/cool when the boiler cuts out, so it goes without saying the radiators are not getting warm. The system is up to pressure and fully vented. It doesn't always trip the heatbank overheat stat or the safety limit stat, but still shuts down.

The DHW works find and the water is piping hot, however the CH outlet pie also gets hot even though there is no demand for CH.

Reading previous threads (bobb and croydencorgi back in 2004) my suspicion is the diverter valve stuck predominantly bias towards the HW side, but passing a little to the CH side. Does this sound feasible?

Any idea how the diverter actually operates? I can see the coil and small feeder pipe, but how does the device physically switch from one system to the other ..... and can it be manually operated/over-ridden to allow the CH to operate over Christmas until I can source an new one?

Any useful answers welcome late on Christmas Eve.

Thanks

 

[cross thread]

most likely the d valve could be the small weep tube blocked

 

[Keith D]

Thanks for the reply.
What does the weep tube do?
Can the d valve been manually operated?

 

[evsy01]

Weeps

 

[petit_pablo]

Thanks for the reply.
What does the weep tube do?

Allows the water to be dispersed from the diverter as it moves.

Can the d valve been manually operated?

Nope

 

[smagsmith]

Hi,

I have the same issue. Did you get a resolution?

Cheers
Steve