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Z Wave heating controls

DrXerox

Established Member
I have recently discovered z wave home automation and bought myself a Veralite and a plug/socket dimmer just to experiment with.

I would like to add some central heating control. I have a combi boiler with eight radiators some of which have mechanical trvs. Control at the moment is done by a Honeywell CM927 which is a 7 day battery operated wireless controller and boiler interlock, and is wall mounted in the hallway.

I would eventually like some zone cotrol. Perhaps a zone for each bedroom, one in the lounge (two rads), one in the kitchen and one in the hall. This could be achieved with something like the StellaZ trv.

Here is where I need some advice.

I could replace the CM927 with a Secure SCS318 and boiler relay to start with, which is a direct equivalent, but z wave enabled. Wife friendly, as time/temp changes can be done from its panel. Then add z wave trvs as I go along.
But, when the hallway is warm enough the boiler will cycle down so any trv radiator won't get heat no matter what it's temperature.

Or I could do away with the programmer and just use z wave trvs and use the Veralite as the programmer. Not wife friendly ahough an iPad app will come into play. But this does away with the boiler interlock. (not recommended)
Or I could replace the CM927 with a Secure SRT322 thermostat and boiler relay, in which case the Veralite would do the programming. Not wife friendly either!

I can't work out the conflict of using trvs (and lots of zone control) with not having a boiler interlock.
Any advice will be greatly appreciated.
 

neilball

Prominent Member
Are there not any products which receive the heating demand from the z-wave TRVs to allow the boiler to be demand-controlled?
 

DrXerox

Established Member
Not as far as I know, but will stand to be corrected.

You can get a power relay, such as those made by Fibaro. I think these are a simple z-wave controlled on/off switch. Not specific to boiler/heating control and as a newcomer probably beyond my understanding. (at the moment)
I guess you would need to associate all the trvs with the relay.

As you can probably tell I'm new to all this.
 

RajP

Distinguished Member
I have just taken the plunge with Fibaro HC2 and a lot of relays and sensors... For me these questions were very well answered and all the guidance provided by Vesternet.. Worth asking them on their chat on their website..
 

cybericius

Novice Member
Any help to achieve the attached plan and topology? Any of those? Thanks.
 

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Deleted member 24354

Guest
Why not just use a nest or hive as a principal boiler controller, then allow the TRVs to adjust the local temp?All will talk happily to your Vera. The advantage with using a home controller is that you can mix and match your technologies
 
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Deleted member 24354

Guest
The Popp ones look like the Danfoss but provide better feedback to the controller. Not cheap but will be what I am migrating to as they get excellent reviews
 

PsyVision

Distinguished Member
Just been reading the reviews of that on Vesternet and Amazon. Not much difference in price from the Tado ones that I currently have installed. The battery life on those and the Danfoss ones is reportedly good, better than others. The Fibaro ones look good but not sure they're worth the extra £12
 

JulianDS

Established Member
I have been looking to do similar and noticed that Honeywell now do a zwave version of their T6 thermostat ('T6 pro'). I'm not sure if it's available in the U.K. But if so might be worth a look? I have little knowledge on this so also keen to learn
 

PsyVision

Distinguished Member

That's the one that @mushii mentioned, the Popp one (which looks the same) apparently reports the ambient temperature as well as the target, something the Danfoss apparently doesn't.

@JulianDS I have been considering switching out my Tado for a Honeywell system, so the T6 sounds interesting. I presume it's z-wave control of the thermostat but not to TRV's, any idea whether the T6 would allow TRV/zone control over z-wave?
 
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Deleted member 24354

Guest
I am going to keep my Nest as my wife and family love and understand it. I will be replacing some of my TRVs with Popp ones, talking to Homeseer. Then if a target room temp is not attainable after a given time, homeseer will either automatically increase the house temp on Nest untill the set point is reached or notify me that a room is colder than ideal and ask to increase the temperature on the nest. As rooms like my wife's yoga room and the cinema room are rarely used daytime in the week, homeseer will turn the heat off in those rooms until the evening. Whereas my office is used daily and I want it warm by 7.30 am when I want to start work and bedrooms can be turned off during weekdays after 8am.
I am hoping that I can bridge both worlds (Popp TRV and Nest) using Homeseer.
 

PsyVision

Distinguished Member
If the room with the Nest is at say 20, but your office is at 15, would you then set the Nest to say, 25 to make it come on (but obviously with the TRV in the Nest room off) ? I guess you'd have to work out how to set the target temperature appropriately?

Or am I missing something obvious?
 
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Deleted member 24354

Guest
My Nest lives in my hallway and has its daily program, but currently the whole house temp is governed by that. I think what i am looking for is to be able to shut rooms down when not in use. It is unlikely that the TRVs will ever be higher than the Nest, but if they are, I need to decide whether to let Homeseer increase the Nest temp on its own, to compensate for a TRV not meeting its set-point or whether it flags it to me SMS / Email etc and lets me manually over-ride the nest temp.
I would need to learn how long a TRV needs, to increase a room temp to a set-point before it flags that it has not met its desired temperature. There is some learning here. Effectively NEST will act as a general controller that the family can use for the main living areas. The Popp TRVs will be used mainly to shut down rooms that either do not require heating during certain hours (when other areas do require heat) or to moderate areas that get hotter than the Nest set-point (eg my rooms on the second floor get much hotter than the rest of the house as heat rises through the staircase) and there is no point in these radiators being on if natural convection can heat them (although they need to be on first thing in the morning until the house gets warm).

I am very familiar with industrial BEMS control and am looking for Homeseer to become a BEMS in my home. Not all radiators will get smart TRVs as this will overly complicate things from both a user point of view and from a programming perspective.

Additionally if a room is too cold, rather than people messing with TRVs they can ask Alexa to increase the temp in that room.
 

JulianDS

Established Member
The T6 pro can be controlled via a zwave hub which controls it, it cannot in turn control other devices as far as I know.
Essentially I would use it in place of the usual nest solution, possibly with some TRV as well like mushii
 
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chrisfraser05

Established Member
If the room with the Nest is at say 20, but your office is at 15, would you then set the Nest to say, 25 to make it come on (but obviously with the TRV in the Nest room off) ? I guess you'd have to work out how to set the target temperature appropriately?

Or am I missing something obvious?

This is exactly how I do it. Or at least its similar.

I use a Zwave Stat and boiler receiver.

If a single room is below the setpoint the main stat is, and also if the window in that room is closed, i turn the TRV hallway (where the stat is) down below the stat temp and force the boiler switch on. That way all the heat is directed to that room.

Under normal circumstances the TRV in the hall is set to 25 so always allows flow to the hall, but I have throttled that one back enough normally all rooms heat and shut off before the Stat reaches setpoint.

Each room's setpoint follows the Stat normally, unless the window is open (drops to 12) or if you boost it (turns to 22 and the boiler kicks in).

All if this is managed with Events in Homeseer.
 

chrisfraser05

Established Member
a good example of how this works is if we have a bedroom window open. The rest of the house will heat except that room.

As soon as you close the window the set point returns to normal for the room, if the room is below that of the stat the heating kicks in warming that individual room back up.
 

arachnoid

Established Member
Thanks for the inputs above. Also considering something along these lines (Nest with z-wave TRV's). I'm running OpenHAB on a raspberry Pi with AeroTec Gen 5.
 
Hi All,

New here and just bought my first Nest v3 Thermostat (bargain off friend) not even installed yet and looking at future plans for zone TRV planning.

Was looking at a Vera plus for going z-wave TRVs and possibly occupancy & temp sensors.

Main issue I can see coming is the Y-plan heating system boiler enabling and heating valve switching etc. as the Nest will have this under control from its Heatlink box. I assume I will either have to parallel wiring demand with relays per demand and trigger that with the Vera as well.

Does the Nest have a software demand to get around doing this anyone knows of?

Failing that, or just to make me aware, can you suggest other options (and go easy I am new to the systems out there please).

Thanks in advance.
 

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