Adding HR92's to a zone?

[captain_planet]

Hi folks.

I'm a bit confused about my evohome setup. I think there's a similar (unanswered) question here: viewtopic.php?f=4&t=4278

Originally it was designed to have 3 zones - underfloor heating, upstairs and downstairs. And it works well. For this configuration I have:

4 wireless BDR91 actuators (upstairs zone, downstairs zone, underfloor heating zone, hot water)
4 zone valves
Hot water kit
2 wireless single zone sensors (for upstairs and downstairs zones)

Anyway, with all this homeworking I've been using my office room (part of the 'downstairs' zone) but it's typically colder than any other room in the downstairs zone (considerably!). So the radiator needs to be on for longer.

Now here's where i'm starting to get confused.

In my downstairs zone, I have 4 radiators (living room, utility, hall and office).

My thinking was that I could buy 4 x HR92's to add finer control. However, i'm now thinking that if i did this, in order to heat my office radiator on it's own, I would have to:
- Turn on my downstairs zone to the same temp as my office HR92
- Turn on my office HR92
- Turn off my living room, hall and utility HR92s

But this feels a bit clunky? I expected I would be able to configure it as:

ZONE - Downstairs (Zone Valve)
......ROOM - Hall (radiator Valve)
......ROOM - Living (radiator Valve)
......ROOM - Utility (radiator Valve)
......ROOM - Office (radiator Valve)

So that when the downstairs zone is turned on, then all HG92's are turned on. However if the downstairs zone is off, and i just want to heat up one room(office), I could turn my office HR92 on independently? However at the moment if I turn the office HR92 on without the downstairs zone being on, it won't heat up?

Any advice please? Thanks in advance.

[Richard]

OK, so if you change an entire zone (in your case the downstairs zone to HR91/HR92 Radiator Controllers), then you don't design a 'zone in a zone'. What you would need to do is rewire and reconfigure your evohome system to a 'Figure 4' application.

You would need...

Downstairs BDR91 rebound as a 'Appliance Relay' (renamed since the 19.33 firmware update) and attached directly to the boiler wiring (normally where the zone valve orange wires attach to).
Zone Valve for 'Downstairs Zone' completely electrically disconnected and left/wedged open in the manually open position.
HR91/HR92's fitted to all downstairs radiators.
Upstairs Zone, UFH Zone and Hot Water zone valve orange and grey wires disconnected and made safe.
evohome system rebound as Hot Water Only system (through guided hot water configuration), Upstairs Zone and UFH Zone rebound as 'single zones' and HR91/HR92's bound in as Radiator Controller zones.

This would then work the way the Honeywell Home team have defined for this type of application.

[captain_planet]

Thanks for the response. I think I can understand the logic behind everything except:
"Upstairs Zone, UFH Zone and Hot Water zone valve orange and grey wires disconnected and made safe."

I don't understand why I would need to change these zones? Please can you explain?

[captain_planet]

One more question please....

Typically in my current zonal system, I create a zone on the evohome controller (downstairs) and bind it to the BDR91 for the downstairs zone. Then if the heating is on according to schedule or otherwise, the controller sends a signal to the BDR91, which opens the zone valve and the boilers sends hot water.

In the 'new' setup, what would i bind the BDR91 to? Presumably the HR92's send a signal to the controller, which somehow needs to send a message to the 'downstairs' BDR91?

[captain_planet]

I'm thinking i might need to go in to Settings > System Devices > Boiler Control > Wireless Relay Box > bind my 'downstairs' BDR91? Hmm...

[captain_planet]

All sorted now - thanks for the pointer.

[Richard]

All sorted now - thanks for the pointer.

Cool...

[Jpap2202]

How did u resolve this.. I have the same issue?

[MrWarrior]

I also have the same issue. Could you please point me in the direction of "Figure 4' documentation? I have attached HR92 in my office (same scenario) but at the moment there is nothing to tell the system to open the "downstairs" valve and the boiler does not fire up

[captain_planet]

I'm MONTHS late in responding to this, but I've had to come back to find my old thread! And my last post annoyed me it was so vague! So, I'll try and be less vague this time.

The link to the "Figure 4" wiring diagram is on page 43 of the manual here: https://homecomfort-techlit.resideo.com ... 01uk07.pdf

Typically the temperature sensor would send a signal to the EvoHome controller, which would send a signal to the BDR91 (actuator/wireless relay), which would send a signal to open/close the valve when calling for heat. In this "Figure 4" scenario, the BDR91 skips the valve controls the boiler directly.

Example

Previously my downstairs zone (controlled by a single zone thermostat - T87RF2033) would send a signal to the Evohome controller, which would send a signal to the downstairs BDR91 (actuator/wireless relay) which would open/close the zone valve when calling for heat.

After the "Figure 4" rewire, each downstairs radiator valve (HR92) is bound to the EvoHome controller as a separate zone. We then configure the downstairs BDR91 actuator (wireless relay) to control the boiler (via binding in System Devices > Boiler Control). Now, when a radiator valve sends a signal to the EvoHome controller, the controller sends a signal to the downstairs BDR91 to call for heat, bypassing the downstairs valve (which I think is now redundant).

Apologies if I've got any of this information wrong (I'm a novice!) but it might give others an idea.