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Thread: Honeywell CM Zone - basic questions

  1. #1
    Automated Home Jr Member
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    Default Honeywell CM Zone - basic questions

    Hi,

    I'm considering using this system to replace a programmer that's giving trouble at the moment. We've a normal system with oil boiler, radiators and hot water, fully pumped. All the radiators have TRVs.

    I have a few basic questions about the CM Zone system, not easy to answer from the info to hand.

    (1) Do I need to have HR80s on all radiators? A number of rooms have two radiators each, and clearly the two would never need to be controlled separately. As far as I can see, they'd both need HR80s, but I wondered if there's a "trick" to get around that.

    (2) Reading the info it appears that you set a single setpoint for each zone and time range. Is this correct? I find that hard to believe. When I first saw the system I assumed that each HR80 would be working to its own separate setpoint to give independent control. If it doesn't it makes it almost worse than conventional TRVs - which can at least be set differently in different rooms.

    (3) How does hot water fit into all this? The documentation makes no reference at all to control for DHW.

    Thanks in advance, Tony S

  2. #2
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    Default CM Zone issues

    Hi Tony, it looks like we're trying to do the same thing - see my post from Saturday. So far as I've been able to understand all HR80s will pick up the setpoint from the controller so they will all follow the same temperature profile. One way around this is simply to not bind the HR80 to the controller so it works as a manual TRV - but then you may as well stick with the original mechanical version (this does work though as I've just done it on one I've bought to check the fit with my existing TRVs). Beyond that you have to have multiple controllers to cover each zone you want to run seperately. It gets confusing here because there are different models around and the documentation supplied isn't very clear. I have an old CM67 and a new CM927. There's also the CM67z which covers two zones (I should have bought this instead of the CM927). The documentation with the CM927 doesn't give any instructions at all on adding HR80s to the system. I've found an installation guide for a 'Wireless Domestic Heating Zoning System' which is for a pack with a CM76z, boiler controller and 6 HR80s. This does give good instructions on how to install everything see: http://content.honeywell.com/uk/home...ide%20(UK).pdf After hours of hunting for documentation on the Honeywell web site this is easily the most useful thing I've found!

    If you dig out anything yourself I'd be grateful to get a copy!

    Cheers,

    Peter

  3. #3
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    Thanks for the info Peter. Reading that guide suggests that you can only have a single setpoint for all radiators within a zone. To be honest that seems pretty useless - a real step backwards from standard TRVs, and quite disappointing.

    In my case, I haven't yet bought anything, so I guess its back to the drawing board to look for something better.

    Ideally I'd want optimum start, weather compensation and an easy manual over ride for run-on or boost. Given that all these were perfected for commercial buildings in the early '80s they should surely have filtered down into the domestic market by now.

  4. #4
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    I agree. I hope someone from Honeywell is monitoring this forum and takes some notice. You can get around it by installing enough CM67z so you can control each room individually but it gets expensive (and HR80s are already expensive). After that you're looking at the Hometronic system which looks brilliant and does exactly what you and I want but is also expensive and bizarrely only sold through one company in the UK - which no doubt makes it even more expensive (and harder to get detailed information on).

    What I find most frustrating is that the control systems companies (and Honeywell in particular) seem to think that end users are too stupid to understand how a central heating system works and will only deal with installers (or they just can't be bothered). Yet most installers have no interest in whether my heating system helps me save energy or has better controls and just want to install the most basic system which is easiest for them - and with the bare minimum of functionality to explain to their customers. Those that do bother treat it like a deluxe bespoke service they try to charge ridiculous amounts of money for.

    With the market for products to improve energy efficiency (and save money) clearly taking off in the current environment I hope the people at Honeywell finally realise that to sell this stuff they need to target the end user and provide much, much better support than they do now.

    If you do find any better alternatives to the HR80 please let me know!

    Peter

  5. #5
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    It seems like you have the CM-Zone system just about sussed. For what its worth I thought I would share some of my experiences of this system, being an existing user.

    We have a 4 zone set up with 16 HR80ís, 1 Boiler Relay & 2 Room Units. We have 16 standard radiators, all with HR80ís and 2 towel rails, both fitted with standard TRVís. Apparently you can expand the system to a maximum of 8 zones by using 4 room units, however, 4 zones seems adequate for us, as we generally donít need rooms on the same floor at different temperatures as most of the house is in use at various times.

    We have 3 different heat sources, so the boiler relay is used to trigger a series of relays & valves, based on the most appropriate heat source.

    The main benefits over standard TRVís and the reason why we went with this system, is the ability for the HR80ís to control the heat source and to set different temperatures in different zones at different times. The main gripe of our previous 2 zone, 2 thermostat & TRV system was lack of control. The conservatory and 2 of the bedrooms were always cold and the rest of the house was warm. The CM-Zone system has solved this problem. If any HR80 within a zone is below set temperature it will call the heat source and open the valve. You can set the temperature manually on each of the HR80ís or turn them off completely, although at the next set point the setting will be overridden.

    We have had the system for about 6 months now and to date it has been 100% reliable. I would think that the financial cost of the system (ours was about £1000) would be impossible to recover from fuel savings alone, but it has definitely made the house much more comfortable.

    Regards Sooty

  6. #6
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    Thanks for the comment. And I'd still need a separate programmer for the DHW.

  7. #7
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    Thumbs up No - CM Zone is wonderful, so long as you don't believe the documentation!

    CM Zone has proved wonderful, and we reckon it's payoff is about 2 years in energy savings alone. Here's why.

    We've found CM Zone give us really effective individual control for each room.

    We've got a large house here, and all but the main room are on two switched water circuits: one for the bathroom, the other for everything else (what's the technical term for 'water circuits'?)

    It turns out that a user can temporarily override the temperature on an HR80, and that override stays until the next time the temperature setting changes on its CM67z controller for that zone. What's more, you can set the 'upper setpoint limit' (USL) for the HR80UK to something reasonable, like 18C. [Warning: the installation guide doesn't mention this, and claims you can't set the USL below 21. Ignore that bit - it's just not true.]

    So for most of our rooms, the ones we don't use regularly at the same times each day, the radiators are all on the same CM67z controller and zone. This just alters temperature between 5 and 5.5 at the times we want the radiators to turn off - typically mealtimes and midnight. To switch on any radiator, we just twist the HR80 knob on top half a turn clockwise - that sets the thermostat to 18 (the USL) until the next turnoff time.

    The effect is that we've got immediate heating anywhere we want - and that heating turns off automatically. And the boiler and pumps only activate when there's demand. That's saved us masses with rooms like studies, the tv room, spare bedrooms etc., which are used irregularly Now we're only heating them when there's someone actually using them. Two years ago we had horrible heating bills as we and our guests left heating on everywhere; this year our bills were around 1000 GBP less - which has paid most of the installation costs.

    Of course we have a few other zones for rooms like the main bedroom and bathroom where we _do_ want the radiators to come on at the same time each day.

    And the radio seems completely unfazed by masses of thick walls (unlike Wifi, bluetooth, etc., etc.)

    [No - I don't work for Honeywell; I've just come to love the product!]

    - Charles
    Last edited by CharlesW; 16th January 2008 at 11:42 PM.

  8. #8
    Automated Home Sr Member NeilUK's Avatar
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    Quote Originally Posted by TonySmith View Post
    Hi,

    I'm considering using this system to replace a programmer that's giving trouble at the moment. We've a normal system with oil boiler, radiators and hot water, fully pumped. All the radiators have TRVs.

    I have a few basic questions about the CM Zone system, not easy to answer from the info to hand.

    (1) Do I need to have HR80s on all radiators? A number of rooms have two radiators each, and clearly the two would never need to be controlled separately. As far as I can see, they'd both need HR80s, but I wondered if there's a "trick" to get around that.

    (2) Reading the info it appears that you set a single setpoint for each zone and time range. Is this correct? I find that hard to believe. When I first saw the system I assumed that each HR80 would be working to its own separate setpoint to give independent control. If it doesn't it makes it almost worse than conventional TRVs - which can at least be set differently in different rooms.

    (3) How does hot water fit into all this? The documentation makes no reference at all to control for DHW.

    Thanks in advance, Tony S
    To answer your questions in order:

    1) If you want to control the radiators using the CM67 then yes they will need HR80s. You may decide that rads in hallways or cloakrooms do not need to be directly controlled and therefore leave the standard TRV fitted. These uncontrolled rads will then be able to heat the room if any HR80 is calling for heat.

    2) A CM67 has 2 zones as standard and each zone has upto 6 time periods per day. If you need more than 2 zones then you need to use multiple CM67s. Note that the HC60NG can be registered to upto 4 devices so upto 4 CM67s can send heating demand to the boiler. If you have more than 4 CM67s then you need to add an additional HC60NG and wire it in parallel to the boiler along with the 1st unit.

    3) There is no provision for hot water control with CM Zone, you need to use a separate single channel timeclock wired through the cylinder stat & onto the control valve.

  9. #9
    Automated Home Sr Member NeilUK's Avatar
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    Quote Originally Posted by TonySmith View Post
    Thanks for the info Peter. Reading that guide suggests that you can only have a single setpoint for all radiators within a zone. To be honest that seems pretty useless - a real step backwards from standard TRVs, and quite disappointing.

    In my case, I haven't yet bought anything, so I guess its back to the drawing board to look for something better.

    Ideally I'd want optimum start, weather compensation and an easy manual over ride for run-on or boost. Given that all these were perfected for commercial buildings in the early '80s they should surely have filtered down into the domestic market by now.
    CM Zone gives you self-learning optimum start and simple zone override (either at the HR80 or the CM67) on a zone-by-zone basis already and weather compensators are readily available as an add-on controller (not necessarily from Honeywell). Weather compensation is not really suited to most systems, not many people would want to install a 3-port mixing valve & pump to their system and direct boiler compensation would cause corrosion damage to conventional boilers leading to premature failure.

  10. #10
    Automated Home Sr Member NeilUK's Avatar
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    Quote Originally Posted by PeterH View Post
    I agree. I hope someone from Honeywell is monitoring this forum and takes some notice. You can get around it by installing enough CM67z so you can control each room individually but it gets expensive (and HR80s are already expensive). After that you're looking at the Hometronic system which looks brilliant and does exactly what you and I want but is also expensive and bizarrely only sold through one company in the UK - which no doubt makes it even more expensive (and harder to get detailed information on).

    What I find most frustrating is that the control systems companies (and Honeywell in particular) seem to think that end users are too stupid to understand how a central heating system works and will only deal with installers (or they just can't be bothered). Yet most installers have no interest in whether my heating system helps me save energy or has better controls and just want to install the most basic system which is easiest for them - and with the bare minimum of functionality to explain to their customers. Those that do bother treat it like a deluxe bespoke service they try to charge ridiculous amounts of money for.

    With the market for products to improve energy efficiency (and save money) clearly taking off in the current environment I hope the people at Honeywell finally realise that to sell this stuff they need to target the end user and provide much, much better support than they do now.

    If you do find any better alternatives to the HR80 please let me know!

    Peter
    Have you looked at the CM-Zone website (http://www.cm-zone.com)? It does give some useful info about the system under the "installer" section. I don't know why it does not include the installation instructions for HC60NG or CM67/CM927 but these can be found by Googling.

    I'd would say that CM-Zone is about as easy as it is likely to get for this kind of control system although I agree it is very difficult to find the technical info online and although it is included in the obx with the kit this does not help pre-sales enquiries! I'm sure if you contacted Honeywell with an enquiry they would email the relevant documentation or get give you the contact details of your local sales rep so you could speak to them directly.
    Last edited by NeilUK; 17th January 2008 at 03:23 PM.

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