Honeywell Evohome with 2 zone heating

[samwardill]

Is there any advice on using Honeywell Evohome with 2 zone heating. Honeywell support are pretty useless and give conflicting advice. They suggested I ask my installer (but my installer suggested I ask Honeywell). I found a support article on the Honeywell Resideo website by Googling "How-to-control-more-than-one-heating-zone-valve-with-evohom". This seems to suggest binding the two port valves (which is not what I want to do).

Ideally I would have HR91 Radiator Controllers on some but not all rads. This doesn't seem like it is supported. I'm not even clear if I can have HR91 Radiator Controllers on all rads in one zone but not the other.

If Honeywell Evohome does not support dual heating zone systems well then does any other system?

It seems worrying that Honeywell don't seem to have a clue how to support this given the fact that Building Regulations Part L 2010 mandate two zones. Even if Evohome makes two zones redundant, it does not seem sensible to tell people just to bind the zones.

 

[John.g]

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[Murdoch]

I don’t know this for sure but I suspect that you’ll need to make sure both zone valves are always open.

each trv will call independently for heat so the heating needs to be able to flow to anywhere (if that makes sense)

 

[EvilDrPorkChop]

Honeywell Evohome Installer here -

Not sure what you're trying to achieve? You want HR91s in one zone, but not the other?

 

[samwardill]

Honeywell Evohome Installer here -

Not sure what you're trying to achieve? You want HR91s in one zone, but not the other?

Why not? Even if I had TRVs throughout it seems crazy that the system can not differentiate where they are and only call for heat to the zone where the TRV is that needs heat.

 

[Murdoch]

I think you will find that it’s Evo Home for everything or nothing. I doubt you’ll be able to mix and match zones

 

[EvilDrPorkChop]

Why not? Even if I had TRVs throughout it seems crazy that the system can not differentiate where they are and only call for heat to the zone where the TRV is that needs heat.

It was a simple question of what you were trying to achieve - as you didn’t explain fully in your original post!

 

[samwardill]

It was a simple question of what you were trying to achieve - as you didn’t explain fully in your original post!

I’d like to control one zone of my house using room based Trvs and the other using a zone thermostat. Even if I ultimately decide to instal smart trvs everywhere , I want the system to use the zones to send heat to the zone that is calling for heat .

 

[EvilDrPorkChop]

I’d like to control one zone of my house using room based Trvs and the other using a zone thermostat. Even if I ultimately decide to instal smart trvs everywhere , I want the system to use the zones to send heat to the zone that is calling for heat .

Yeah you can do that.

Zone 1 with TRVS - remove or lock open the Motorised valve. Disconnect electronically.

Zone 2 - set up as an extra zone controlled by Zone Valve with an additional stat or just the panel as the stat.

 

[samwardill]

Yeah you can do that.

Zone 1 with TRVS - remove or lock open the Motorised valve. Disconnect electronically.

Zone 2 - set up as an extra zone controlled by Zone Valve with an additional stat or just the panel as the stat.

I think I'll get a Drayton Wiser. They have a system that is designed to work with two heating zones (using the motorised valves).

 

[EvilDrPorkChop]

No matter what system you use - you're going to struggle having some rads with eTRVs and not (In different zones). Whenever there is a demand on a TRV on a rad, any rads within that zone that don't have eTRVs on will heat. The zone valves don't make the slightest bit of difference tbh.

You'd need to do one zone fully with eTRVs or not. Drayton won't be any different.

 

[samwardill]

No matter what system you use - you're going to struggle having some rads with eTRVs and not (In different zones). Whenever there is a demand on a TRV on a rad, any rads within that zone that don't have eTRVs on will heat. The zone valves don't make the slightest bit of difference tbh.

You'd need to do one zone fully with eTRVs or not. Drayton won't be any different.

I plan to have eTRVs in one zone but I still think that zone should use the 2 port valve. I think this is how the Wiser works

 

[EvilDrPorkChop]

I plan to have eTRVs in one zone but I still think that zone should use the 2 port valve. I think this is how the Wiser works

Why, as they’d all have eTRVs? You don’t need the zone valve.

 

[samwardill]

Why, as they’d all have eTRVs? You don’t need the zone valve.

The trvs are battery powered and communicate with radio. Doesn’t seem sensible to rely on these over a hard wired mains powered 2 port valve

 

[EvilDrPorkChop]

The trvs are battery powered and communicate with radio. Doesn’t seem sensible to rely on these over a hard wired mains powered 2 port valve

The eTRVs would have to open before the zone valve would trigger anyway? The zone valve is only triggering the boiler - if anything it's an extra thing to go wrong. Why are you bothering if you're that concerned - just leave it as two zones with a smart controller and not bother with the eTRVs