Honeywell ST699

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Yes, the picture of the ST699 is now - those are the linking cables left in after removing the other cables.

My concern is that according to the ST699 installation PDF I linked above there should only be 4 cores connected (L, N, 3 and 8 ) but you had 6 instead (L, N, 3, 4, 6 and 7). I had a closer look at it at lunch time and noticed that the previous owners built a new window sill that is sitting (loose) over the original sill - I lifted it up and the original sill is cold to touch (that window is North facing too which doesn't help matters - there is still snow remaining in front of it even though the rest thawed a week or so ago! All other connections are clear on the diagrams supplied by Honeywell apart from this wire from the boiler to terminal 8. To view the purposes they believe they have legitimate interest for, or to object to this data processing use the vendor list link below.

I guess if you were to turn the room stat down the heating should go off even with a programmer fault if its wired correctly. The other small radiator at the other end is back to back with the kitchen radiator but not sure if that would affect the TRV reading. The old room thermostat becomes redundant because the Hive has both time and temperature control built in, unlike the ST699 which just provides time control. When you have it, post details of it on here and someone will be able to advise you how to install it.

If I used the programmer to also switch the heating on they both came on together, even with the water "off" on the programmer. Trace the wire that comes from the central heating motorised valve to the wiring centre then create the fault by turning the central heating on then off at the programmer. On the plus side in the hall staircase and landing is not connected to the open plan space and the front door is a traditional wood design with thick curtain to reduce the draught in winter, so although the thermostat is directly above the radiator (small double) at light switch level it is still a cold space as it is next to the front door and the radiator has to heat up the stairs and landing too so it sort of still works.The initial fault happened in the middle of the night quite spontaneously, the main switch being on but the CH and HW off. Yes as a default I will just replace the wires to the exact layout of the Honeywell , utilizing the L N 3 and 4 terminals on the Hive.

Tbh, we are going to struggle to take this any further unless you are prepared (and capable) to get a grip with the wiring and get your meter stuck in. Make sure you don;t 'lock' it in a far position (there's a 'notch' on the side of the lever slot where the lever can be 'parked' - make sure it doesn't stick in there and is free to move.Page 3 of the pdf wiring diagram upload attached shows the basic system 2 with room thermostat wiring layout I currently have exactly.

We and our partners use data for Personalised ads and content, ad and content measurement, audience insights and product development. A room thermostat would probably be better, but I was mainly looking for quick (and cheap) fixes to improve the current system. In your photo the wires would appear to be in the correct terminals as far as I can tell from a photo, when you can't see what is on the other end of them all. Not seen a Y Plan using gravity, in the main the DHW is the default mode, and the tank thermostat turns on the boiler for DHW and the tank thermostat when satisfied powers the grey wire which will cause the motorised valve to open all the way so only have central heating, the white wire powers the valve half way if no grey but all the way if grey also live. A note of caution though: some thermostats have a neutral connection and this should be isolated and obviously not connected to a live wire.But I see a post like yours, and I think of my central heating, I have two pumps, two motorised valves, the domestic hot water and bathroom radiator is thermo syphon, no control other than boiler run time as to domestic hot water, and closest plan is a C Plan, I still am not sure of pipe layout, but I have got a wiring diagram of the system.