Honeywell ST699

Product Information

The only reason I wasn't going to bother with downstairs was because we don't really have trouble with the heat levels downstairs, if anything it's hard to keep it warm even when heaters are on constantly as it is a large open plan space and has a very large bay window at one end and French doors at the other. Having said that I suppose it can't hurt to put a TRV on the kitchen radiator as that doesn't really need to be on while we're in there cooking, worth considering I suppose... 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. With the older type of systems, (without motorised valves) it's not possible to have the heating 'on' without the hot water being 'on' as well. These are usually older systems installed before 1980's, but can be upgraded. Changing the Hive to gravity mode just makes it automatically turn the hot water on whenever the heating is selected on.

You can have hot water only, but you can't have heating only - the hot water has to be on for the heating to work, although I have no idea how the two are connected from a system point of view...It's all connected and I've set the time and date, all is okay. However, even though the lights come on, it won't fire up either the heating or the water! Yes, the picture of the ST699 is now - those are the linking cables left in after removing the other cables. I've attached pics of the ST9400C wiring before and after the swap (ST9400c Wiring 1) and a pic of the remaining wires in the ST699. Yes N & L were previously in N & L on the ST699. Regarding the locations of the other cables, I'm pretty certain that I did the following swap, although, I'm second guessing myself now:

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!This has lead me to think that while I'm replacing valves anyway I may as well use the opportunity to fit Thermostatic valves to all the upstairs radiators. I always thought I would need to replace the boiler system to get these but (unless I'm very mistaken) it's just a case of swapping the valves on the existing system. Not so worried about downstairs but our upstairs rooms are very prone to overheating and I think TRVs would really help and save money. 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. No, I meant "have" cables linking on the ST699 as they are still connected. So I disconnected the power supply, the boiler and the water and these were left connected. I can confirm the hot water was never permanently on and came on twice a day. We also have the option of switching on the emersion for water.