Honeywell Evohome - Multi-Room Zones

When we installed the Honeywell Evohome central heating control system we fitted four radiators with HR92 temperature regulating valves (TRV). In the other rooms we left the manual TRVs fitted, and lived with the fact that whenever the Evohome system decided that any of the controlled rooms were getting a bit too cold, then the manual TRV rooms would be getting some heating. So recently we ordered another pack of four HR92s from JTM Plumbing, and have fitted them to the remaining radiators. We didn't do this originally purely because of cost, as the HR92s are not cheap, but the ability to add new HR92s to the system means you can fit out the whole house as and when we can afford it.

As our radiators already have the M30x1.5 valves, installation of the HR92s was as easy as before. Binding them to the Controller was also really straight forward. A long press on the Settings icon is required to get into the system settings menu. Then simply add a zone and give it a name, at which point the Controller will sit and wait for the HR92 to start the binding process. (The only thing to remember is to tell the Controller not to use the temperature sensor in the Controller itself for this new zone.) On the HR92 a couple of presses of the button are required to get it into binding mode, and within seconds the Controller was reporting that the two were bound.

We have an open plan L-shaped lounge and dining room, with a radiator in each 'room'. Previously only the lounge radiator had a HR92, but now both of them have HR92s fitted. We started by copying the temperature schedule from the lounge to the dining room, so that both radiators would be trying to keep this space at the same temperature. This is easily accomplished, by going into the schedule for the lounge zone, and using the icon in the bottom right of the Controller display to copy the entire week schedule to the dining room zone.

However this does mean that if we change a schedule or manually change the temperature setpoint in one of the zones, the other zone is unaffected and the two radiators will be trying to keep the one space at two different temperatures. So we set up a multi-room zone, using both the lounge and dining room radiators. The Controller now allows only one temperature setpoint and schedule for the space as a whole, but the two radiators work independently to achieve the desired temperature. This works really well at dealing with the different thermal characteristics of the space. Our lounge is on the south side of the house with big windows and a wood burning stove in it, while the dining room is on the north side of the house with very little natural warming getting in. Certainly when we fire up the stove, the lounge radiator pretty much shuts down as the stove warms up the lounge. We'll have to wait and see how the system deals with sunny days (I hope!).