<5year old heating system, comprising of (relative to this discussion) Worcester 30CDI gas boiler, honeywell ST9400c programmer (HW & CH) & 2 port Honeywell motorised valves.
Heating is working fine BUT HW is being stopped automatically entering an unvented cylinder by the 2port Honeywell motorised valve.
If I test it by turning controls on/ off & listen for the valves to open/close, they sound like it works as should but when I put the system back on timer then the HW fails to get past the motorised valve again.
If I manually open the motorised valve, the hot water floods in.
Ive changed the motorised valve head BUT still the same problem - any ideas?
Heating is working fine BUT HW is being stopped automatically entering an unvented cylinder by the 2port Honeywell motorised valve.
If I test it by turning controls on/ off & listen for the valves to open/close, they sound like it works as should but when I put the system back on timer then the HW fails to get past the motorised valve again.
If I manually open the motorised valve, the hot water floods in.
Ive changed the motorised valve head BUT still the same problem - any ideas?