Honeywell ST699

Product Information

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. to the terminals of the dual channel Hive that have exactly the same functions. So N goes N, L to L, Hot water on, to Hot water on etc... 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. Find a Plumber Plumbers Looking for Work - Post Here Looking for a Plumber? Post Jobs Here Looking for a Heating Engineer? Post Jobs Here Find a Renewable Energy Specialist Plumbers Directory Listings 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.

You had a hard wired link between Live, 5 (common for CH) and 6 (Hot water on). That's why I thought your hot water was permanently on. There was also a hard link between 3 (CH on) and 7 (HW off). Then there were connections to all four terminals for CH on/off and HW on/off which is not normal. So I wonder if the other end of those wires go to the expected places.

I've been doing a lot of research on heating systems recently, and for those that have seen my other topic I've been having trouble with a cold radiator which I think will need new valves.

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.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. 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!