Honeywell Evohome w/partial zoning

[markocosic]

Honeywell evohome:

http://www.evohome.info/


The base unit isn't outrageous but the eTRVs are costly. £200 question: can we do the following?

Fit the base unit in the open plan kitchen/living room/diner then use the base unit to control that zone.

Fit standard TRVs in the two bathrooms.

Fit the honeywell eTRVs in the bedrooms such that each is their own zone.


Will a "call for heat" from the eTRV zones override the base unit's control over that always-on main zone?

Could we then fit standard TRVs to the main zone, set to say 21C, such that even if the eTRV zone did all for heat it isn't going to cook the main zone. (but if it drops below 21C the base unit can still call for heat for that main zone)


It's the difference between 4 eTRV heads and 8 eTRV heads. I guess if devious we could put lockshield valves only on all those downstairs radiators then pipe them through a single TRV with electronic head on it for 5, but that's a little kludge like.

 

[Simony22]

You can install it as you have described but it would defeat what evohome is designed to do, standard trvs won't give you the accuracy of the hr92s and you would get a conflict of the trvs being open at a time when you only want a single zone on but pottentially heating 50% of your house. A 4 pack is available cheaper than 4 individually, I would bite the bullet and purchase all 8 that u need, I've had the system for 4 months and the control it gives you is amazing, it will pay for itself in a short space of time!

 

[Dan Robinson]

So how is the kitchen zone controlled hydraulically?


Evosl's biggest problem is champagne ideas and beer money from home owners.

No you don't need to put hr92s everywhere, but you need to omit them strategically.

I.E. Bathrooms and hallways. There's no point not having bedrooms in the system.

Having a mix of standard trvs and hr92s in a zone/room is wrong.

 

[markocosic]

The house is presently a blank canvas (ex electric ceiling heating) so can be plumbed to suit.

 

[Dan Robinson]

Then why use EVO? It is supposed to be an alternative to a re Plumb.

 

[markocosic]

What's the alternative solution for zoning a blank canvas?


Looked briefly as this gear:

http://www.ebay.co.uk/itm/271455065018
https://www.aqualec-ufh.co.uk/index.php

Manifolds and actuator heads are cheap but where are the pukka controls?

 

[Dan Robinson]

How many zones do you reeeealllly need?

I am all for zoning - but it gets mental when people get the bit between their teeth without actually thinking it through.

Piping to a manifold gives you future flexibility if needed.

Otherwise, pipe to floors/zones of the house separately and use DT92e's with Evo and BDR90's to control a normal S-Plan plus.

 

[markocosic]

5 zones.

4 study bedrooms (each individual)

Open plan common area (one zone)

Bathrooms can be always on with standard TRVs to limit temperature rise.


If it were a private home with more regular hours/only sleeping in the bedrooms it'd be 2 zones (bedrooms, communal) with bathrooms always on.


Zone valve via HC60NG, BDR91, or BDR90 (less common?) for the big zone if you want it:

http://www.ebay.co.uk/itm/like/221427304150

http://www.ebay.co.uk/itm/New-Honey...it-for-Wireless-Room-Thermostat-/231225668966


Else a 4-pack and hook them together in software afterwards:

http://www.plumbnation.co.uk/site/h...kit-hr924uk/?gclid=CN7Ds7rXnr4CFQeWtAodIyMA-A


That's probably worth the hassle for £175 saved; thanks!

 

[Dan Robinson]

Are you asking or telling?

 

[markocosic]

Telling/thanking for the relay box and standard one valve suggestion

 

[Dan Robinson]

You might have issues with the hc60 add it is not a 2 way device.

 

[markocosic]

Ok if in the same 'zone' as the main control unit (which has the temperature sensing part inside) unless I've missed something?