Whilst wire colours do necessarily mean anything on a central heating system, the combinations you have are a bit unusual. For example blue being used for CH on & HW on and brown for hot water off. That's based on your indication above about wiring on ST699. I assume the current picture of the ST699 is after it has been removed from the wall and it's sitting on a table so to speak. Do you have a multi meter and able to trace the wires, in theory one core provides the live input to the boiler (#8) and one the live input to the pump (#3). I can see from your photo that there are two separate cables as the wires going ino terminals 1,2,3,4 on the ST9400 as they have slightly different characteristics If so, you have a fully pumped system, but it's not being used to its full ability because the ST699 has not been wired correctly. Fortunately the changes I mentioned (motorized valves!) will not be necessary. It's just a case of installing a new programmer, correctly wired, and a thermostat. Just think what if your away for a while in the winter and it was like last year and the power goes off. For 5mins work and 5 quid could save you loads of hassle.

I'd recommend you tidy the wires a bit. The number of loose strands is a disaster waiting to happen. You have what they call BASIC SYSTEM 1 or 2. Gravity hot water, pumped CH and with/without room thermostat. Now just need to see how that maps to the ST9400. However you should ensure you know what went where on the ST699. The use of three blue cores, two brown cores and one red core coming into the ST699 is a recipe for confusion. Strangely enough the links between terminals is the least of the problems. Unfortunately the part did not fit, with the attachment being too large. This does make me wonder why you are advertising indesit parts, that do not fitAlso on your prior ST699 connections. The hard link from L to 5 means that when the hot water was "off" power would have gone across to 3 (CH-On)

Thanks for bringing this to our attention, this has been a recent change to our system. We agree with you that it is not quite right and we have now edited our system so as not to be so confusing. Ideally I would like a modern digital timer with flexibility for multiple programmes for different days and times and a wireless thermostat in the living room to control the temperature. And one that doesn't lose all it's settings whenever there is a power interruption! Whilst Hive has an earth terminal it isn't actually connected to anything. Hive doesn't need an earth connection itself. The terminal is just there to 'park' any earth wires that happen to be present and keep them together so that they are safely out of the way of the other terminals. The bypass provided a path from flow to return if both valves are closed buit the pump is still running. The manual valve should be replaced by an automatic bypass valve. I do know that there is a Grundfos pump in the airing cupboard next to the cylinder and two white boxes connected to the pipes which I believe are motorised valves, but that is the extent of my knowledge - the airing cupboard is a bit of a spaghetti junction or pipes and wheel valves, and I don't really know what any of them do! I just opened them all when I first moved in and hoped for the best, I've never touched them since lol.As you have power & lights on the ST9400C i guess that "Blue-A" and "Brown-B" were previously in ST699 N & L respectively. But can you say of the other four which terminals on the ST699 did they originate. I opened up the Honeywell wiring hub near the boiler power switch to try to get a better idea of what the wires were doing