three way valve

[Anthony999]

I have recently installed a Horstmann 3 port valve.
Now the central heating does not work until the hot water reaches full temperature (or the hot water is switched off).
The indicator status lamps on the valve show the correct status. (ie HW & CH) for all demand combinations.

Any help would be much appreciated.

 

[doitall]

It wont if you have fitted and diverter valve instead of a flow share valve what model is it

 

[ChrisR]

Is there a balancing valve on the HW?
If not, esp if the pumps old, it's doing what I'd expect.

 

[Anthony999]

Sorry for the delay in replying.
The new valve is a Hortsmann Z322.
The whole storey from the beginning..
The system is approx 30 years old. (Although the pump has been replaced.)
On three occasions over the last month the overflow from the header tank has run.
The water in the header tank has been hot. (But not the expansion pipe was not hot.)
I started checking through the system and found that the room thermostat was not operating the valve. The stat was OK and I replaced the valve which now gives the current problems (the indicator lights HW and CH work correctly and the shaft from the motor moves to the correct position) but the radiators only warm when there is no demand for hot water.
I have currently wired the valve as a diverter valve biased for the CH. but this is only a temporary solution.
Is there any way of balancing the flow between the CH and HW? There are no taps on the feed the heat exchanger on the hot water tank.
Is there an underlying fault which needs rectifying?