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- 8 Mar 2022
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I have a Worcester Danesmoor (circa 1990) oil fired boiler with Honeywell Y plan control system. All been working fine for many years, but I now have a strange problem. As of this weekend we are having an issue with Heat vs Hot Water.
With CH On and HW Off from the programmer then CH works fine. When room stat demands heat, boiler and pump run; when room stat has no demand then boiler/pump stop. HW doesn't heat (as expected).
With HW On from the programmer boiler never fires and pump doesn't run. Makes no difference if cylinder stat is demand/no demand or if room stat is demand/no demand. Also makes no difference whether CH is On or Off on programmer, the boiler won't run so long as HW is On.
Have tried swapping Mid Position valve for another one, no change in behavior, valve makes all expected movements.
Any help appreciated.
With CH On and HW Off from the programmer then CH works fine. When room stat demands heat, boiler and pump run; when room stat has no demand then boiler/pump stop. HW doesn't heat (as expected).
With HW On from the programmer boiler never fires and pump doesn't run. Makes no difference if cylinder stat is demand/no demand or if room stat is demand/no demand. Also makes no difference whether CH is On or Off on programmer, the boiler won't run so long as HW is On.
Have tried swapping Mid Position valve for another one, no change in behavior, valve makes all expected movements.
Any help appreciated.