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  1. #1
    Automated Home Jr Member
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    Question Z-Wave timer/roomstat?

    Hi,

    Is there a Z-Wave room stat that also contains 7 day timer logic? I must admit I cannot find any - only room stats that expect (I assume) to be controlled by a central programmer.

    I'd like a system where each room is self contained, with the only weak point being the boiler relay - and where the room user has easy and direct access to adjust their programming and temperature.

    Cheers,

    Tim

  2. #2
    Automated Home Sr Member Quinten's Avatar
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    How about a Heatmiser PRT-TS Wifi? I've got 2 of those and using a plug-in on my Vera Z-Wave controller can control them locally, or using the Z-Wave controller...

  3. #3
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    Thanks - yeah - I did look at Heatmiser.

    But I decided the wiring would be excessive and I'd need to drop wires to a thermal wax actuator at the radiator, or have a motorised zone valve in the feed pipe.

    Then I'd also have to "OR" all the outputs to drive the boiler demand.

    My "ideal" system so far is actually the Conrad FHT - but the simplex comms bothers me (it is rumoured to be unreliable when you get too many, say >8-10 controllers babbling on the air.

    Z Wave looked interesting, having some interoperability and following a standard, yet being simpler (unlike zigbee) but having zigbee's mesh routing (subject to device support).

    I am happy with the Stella-Z valve (the Danfoss is rumoured to be unreliable, seem a report where the owner had to pull the batteries out every few days to get it to talk to the network).

    I'm happy with the choices for boiler control.

    What I would like to find is a Z-Wave version of the FHT80B which is a room timer stat.

    That leaves the system composed of relatively standalone components (save the boiler relay and I can have a spare) - but also with the option to remote control everything.

    I am a *great believer* in fancy systems being able to degrade gracefully in the even of faults. I'd even keep a boiler timer ready and wired and a few TRV heads in case the whole system failed

  4. #4
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    How many Stella-Zs do you think you'll have? (Z-Wave isn't a great protocol for running large numbers of battery powered devices)

    And how do you expect the Stella-Zs to fit in with your independent room thermostats?

    By the sounds of it you're asking for each zone to have its own controller that triggers both the Stella-Z and the Boiler Relay. Thats a degree of redundancy I just don't think you're going to find.

    Horstmann do a 7 day Z-Wave programmer, but it only speaks to the Boiler Relay so if you're looking at radiator stats too that isn't going to work.

  5. #5
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    Good questions to which I have answers

    11-12 Stella-Zs

    In most cases, one per room stat, in 2 cases, 2 StellaZs on a single room stat.

    2 StellaZ's will be paired with a 2nd "boiler relay" that actually starts the low temperature mixing circuit (underfloor heating, needs <=40C rather than 50-60C) and I will use simple relay logic to cause a boiler demand from this.

    The rest will be bound with the primary boiler demand relay.

    That's the base system - there will be some central point of control but if that fails, the system should basically operate.

    There are likely to be other ZWave devices (meter readers, odd controls for lighting outside).



    > "By the sounds of it you're asking for each zone to have its own controller that triggers both the Stella-Z and the Boiler Relay. Thats a degree of redundancy I just don't think you're going to find."

    Yes - that sums it up Exactly how you might deploy the Conrad FHT. Well, I can use the FHT if I am careful to test the system is not missing too many messages, but as I said, ZWave looked cute.

  6. #6
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    Right well 11-12 Stella-Zs is possibly pushing it, especially if you're planning to have (battery) thermostats in lots of the rooms and are looking for a responsive system. There is a thread on the Indigo forums about Stella-Zs and the problems of the Z-Wave protocol when you have lots of devices waking up and needing a quick response from the controller. The people behind Indigo have modified the software to avoid it crashing, but with 12 rad valves and half a dozen thermostats I think you're pushing the limits of the protocol from what I've read (certainly enough so such that I went cool on the idea of the system as its a lot of money to discover it isn't reliable).

    Stella-Zs are slave only devices so they can't speak to the boiler relays directly. I'm not sure whether they can take "associations" such that you could have them directly controlled by a thermostat as well as a central controller (and as per my earlier post the only 7 day Z-Wave thermostat I'm aware of in the UK won't pair with anything except its own boiler relay). You might have luck with the Horstmann dial thermostat to give local (but not programmed from the device) control to some extent assuming (i) the Stella-Z can be associated with the thermostat; and (ii) the thermostat gives the right commands to actually be of any use to the Stella-Z. On the latter point it definitely can't send the current set point to the Stella-Z, so the best you could hope for (though it should work) is to set the Stella-Z to 25 degrees with the main controller and then have the thermostat flick it between that and frost protection modes (6 degrees) depending on whether the thermostat thought the room needed heat.

    Whether you can bind half a dozen thermostats with a central controller and also with a single boiler relay (which in turn is bound to the central controller as well) is a similarly questionnable scenario but more likely to work as it really just turns on whether the boiler relay accepts associations and if so how many.

    All in I'm highly doubtful whether you can get anything close to what you're looking for in terms of redundancy if the controller goes down. I also think you're pushing Z-Wave altogether which is why I've abandoned (after a lot of research) the idea of doing what you're looking for relying on central control as well.

  7. #7
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    Quote Originally Posted by TimJWatts View Post
    Thanks - yeah - I did look at Heatmiser.

    But I decided the wiring would be excessive and I'd need to drop wires to a thermal wax actuator at the radiator, or have a motorised zone valve in the feed pipe.

    Then I'd also have to "OR" all the outputs to drive the boiler demand.

    My "ideal" system so far is actually the Conrad FHT - but the simplex comms bothers me (it is rumoured to be unreliable when you get too many, say >8-10 controllers babbling on the air.

    Z Wave looked interesting, having some interoperability and following a standard, yet being simpler (unlike zigbee) but having zigbee's mesh routing (subject to device support).

    I am happy with the Stella-Z valve (the Danfoss is rumoured to be unreliable, seem a report where the owner had to pull the batteries out every few days to get it to talk to the network).

    I'm happy with the choices for boiler control.

    What I would like to find is a Z-Wave version of the FHT80B which is a room timer stat.

    That leaves the system composed of relatively standalone components (save the boiler relay and I can have a spare) - but also with the option to remote control everything.

    I am a *great believer* in fancy systems being able to degrade gracefully in the even of faults. I'd even keep a boiler timer ready and wired and a few TRV heads in case the whole system failed
    I've actually been running a Conrad / HouseHeat / ELV system for maybe 4 or 5 years now and it's proven pretty reliable. I have 10 radiators across 10 rooms with 10 FHT stats and actuators and the boiler control. I also have the FHZ USB controller running with FHEM and a xAP gateway for integration into other HA systems.

    Overall it's been a good experience, each thermostat can be locally programmed and the USB controller / FHEM / xAP gateway give status and control options externally. I've not noticed any communication issues, the actuators on the radiators react pretty quickly to changes on the thermostats. I've got the boiler control to only kick in if an actuator is opened by 8% or more and it's all pretty autonomous.

    With FHEM you have the option of web interface control and iOS and Android Apps plus the xAP gateway gives integration with other HA systems.

    That said, it has one drawback in that the USB controller seems to "queue" any commands you send to it and decides to send them out "when it damn well wants to" This means that it's not *that* great for instantly turning a radiator off or down in reaction to say opening a window or a door.

    I've been looking for a Z-Wave solution myself and am hoping to try some options out soon, but I really want to replicate exactly the same functionality I have at the moment with a completely autonomous system with HA integration overlaid on top.

    Will update this thread if I get any further with a comparable solution!
    Martyn Wendon
    Vesternet
    Check out my Blog!

  8. #8
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    Quote Originally Posted by martyn.wendon View Post
    I've been looking for a Z-Wave solution myself and am hoping to try some options out soon, but I really want to replicate exactly the same functionality I have at the moment with a completely autonomous system with HA integration overlaid on top.

    Will update this thread if I get any further with a comparable solution!
    @Martyn: Any luck with your Z-Wave solution? What have you gone for in the Z-Wave range?

  9. #9
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    Quote Originally Posted by zimguy View Post
    @Martyn: Any luck with your Z-Wave solution? What have you gone for in the Z-Wave range?
    Nothing so far! I *really* want the same functionality that I currently have - each room has a separate Thermostat that can be programmed over 7 days with 2 on/off times per day with 2 set-point temperatures. And each Thermostat can control one or more radiator valve. And each Thermostat reports back to the boiler control - the boiler control only turns on the boiler if 1 or more Thermostat says there is a need for heat. And then the HA control layer over the top.

    I want a lot don't I?

    The closest I think I can get with Z-Wave is with StellaZ radiator valves, Secure LCD thermostats for the local set-point temperature, a Secure Boiler receiver to interlock the boiler and a MiCasaVerde Vera to do all the logic / zone time programming. But that might work out a bit of an expensive solution. I could forego the Secure LCD thermostats, but then I wouldn't have local override and display of set-point & temperature. I'm probably going to go this route since I already have a Vera.

    The StellaZ are good value so I can probably stretch to all 10 radiators in one go and maybe do a single Secure LCD thermostat upstairs and downstairs as in interim solution, adding one per room over a period of time. I also found that the StellaZ can be controlled in "direct" mode - you can tell them exactly what % to open, as opposed to just controlling the set-point - I just need to work out how to do that on a Vera :-) This would be great and allow really fine-grained control of the heating based on *my* logic as opposed to what the TRV thinks it needs to do.

    Whichever way I go, I'm going to be attacking it at the end of this Winter and will have it ready for use next Winter :-)
    Martyn Wendon
    Vesternet
    Check out my Blog!

  10. #10
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    I'm wondering whether the eQ-3 Max! System (also available from Conrad) would serve your purposes. It seems to represent excellent value -

    TRVs - 24.99
    Window sensors 16.99 (causes TRV to shut down if window opens)
    Room Stat - 25.99

    The only "problem" seems to be that there is no "native" boiler control in the system - although I'm confident that you could use A N Other - and would welcome any ideas as to how to go about this.
    Regards,


    Ian

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