Hi there, looks like we have similar heating/hot water system Y plan ( i think) as we have a 3 way mid-position motorised valve and also have the same hot water termostat, (both located in our loft space) however we have another 2 way motorised valve just by the hot water cylinder and also a second hot water thermostat on the hot water cylinder, the 2 way valve was starting to make a loud noise (all times), so i replaced it, bought the same as the old, and replaced it, the issue i noticed was with the wiring, in the terminal box we have 3 wirings ( one is the water temperature thermostat, then a wire from the programmer, and the 2 way valve) when i remover the cover i seen the the brown, blue and the earth wire form the programmer and water thermostat connected together, but from the 2 way valve was only the blue and earth connected together with the programmer and hot water thermostat, and the brown from the 2 way valve was connected alone in the terminal box. the orange and gray wasn't connected anywhere, both were blanked, ( my question is that why the brown cable is in the terminal box if not connected together with the browns from the programmer and hot water thermostat.) any advice#?

Even though Honeywell provided a wiring diagram for use with cheapo connection strips, installer still made a wiring mistake with my Y system. Thing is, most of the time the system worked fine, but sometimes it didn't. Wasn't easy to put right.

Great video 👍 what station:day/time is your radio show on?

Y not thanking you for your efforts 👍

hi there, I have a ST9400C programming unit, and I am trying to replace my old hcw80 wireless thermostat and receiver, with a newer DT90e in the old receiver have a 5 wiring which are (Blue wired in N, then the brown wired in the L (2nd) then I have a black wire which wired in to A, then a grey wired into B and then the earth wired into the E, , do I follow the same with the new receiver dt90e ? if so where do I connect the earth as on the new dt90e there is no E (mark) only C, in the new receiver dt90e I have a NLL then ABC , any advice? thanks