Honeywell ST699

Product Information

Just think what if your away for a while in the winter and it was like last year and the power goes off. 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. If you would like to change your settings or withdraw consent at any time, the link to do so is in our privacy policy accessible from our home page.

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.Sorry it's sideways it's how my phone uploads them and I can't seem to find a rotate button on the site).

Ive had this heating programmer for 20 years and it works fine unless I have a power cut, which happens out in the sticks occasionally. The Hive doesn't need the links between L, and the 'COM' terminals 5 and 8 that the ST699 has, they are already made internally inside the Hive for you. Interesting point about the automatic bypass valve, I might consider doing that when I change all the radiator valves - would it make a big difference do you think? It just seems odd there are 2 wires into the Neutral on the Honeywell and I wonder if the boiler not turning off sometimes is caused by a NC terminal not being connected. It consists of a 7 day CH and HW programmer, with complete independence between CH and HW, and a thermostat which communicates wirelessly with the programmer, so it can be located in another room.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. Sounds like there would be a bit more work involved in sorting the flexibility side out, as well as updating thermostatic room control, so I think I might just leave that bit alone until the day comes that I install a whole new combi-system. I've gone back to the programmer to take a picture of the wiring and noted I'd connected the boiler upto the HW and vice versa ! If so, you gave a "gravity HW, pumped heating" system, which means it would have to be modified to give the flexibility you want. I have noticed however, that the old wiring to the ST699 that is redundant, wasn't as per the diagram I saw in one of the posts.