Can anyone help advise how to move from a cm927 to Evohome please?

[DBMandrake]

That's interesting. I hadn't heard that or seen it reported anywehere but then I haven't spoken directly to Honeywell support with a problem before...

[FUNKYDADDIO]

No need to worry about wiring. Combi boiler already has BDR91 connected to it. Just bind new evohome controller to the existing BDR91 and add HR92s to radiators for zoning.

The ordering options for the controller are shown on the controller data sheet: https://products.ecc.emea.honeywell....-uk07r0814.pdf. If you plan to buy the separate wall mounted charger then the pack without a table top charger may work out, as the BDR91 you already have with the CM927 can be paired with it. You'll notice that if you want a table top charger stand it also comes with a BDR91.

Just the controller at £185 (eg http://www.discountedheating.co.uk/h...ontroller.html) doesn't look to be much cheaper than the Base Pack (with charger stand and BRD91) at £205 (eg https://theevohomeshop.co.uk/honeywe...p921r3100.html) though. You can probably sell the extra BDR91 for to someone who want so set up separate boiler and zone control, or maybe put it to good use yourself to get finer control of things.

You'll presumably want radiator valve heads (HR92 devices) as well. Do you understand the wiring and water valve installation that you have? It'll probably need no modification, but mat be worth reviewing.

That link is pointing to the older 2nd generation evohome controller. For evohome WiFi (current generation) see www.honeywelluk.com/Documents/All/pdf/Honeywell_Evohome_Brochure_ERP_6.pdf

Good point. If you go for the wireless pack linked above that contains a BDR91 too (which in my case I've kept for spares). You could do the reverse (keep your existing one for spares), if your new one packs up...

Although your existing BDR91 will work, these things contain (non-updatable) firmware, so for the sake of a few I think it would be wise to go for a newer one, which will have the latest revision.

As others have said, the very first thing is to figure out what you already have. If you've got a CM927 room thermostat at the moment, you'll already have a BDR91 already. I think you've figured that one out yourself as you're asking whether you need a "new" BDR91.



You're pretty much in the same boat as I was when I started (see this thread).

You need to look at your existing BDR91 and try and figure out what this is connected to and how. It might be as simple as taking the battery out of your existing CM927, clearing the binding on the existing BDR91, and bind it to the new evoHome controller.

In terms of kit you'll need

- a wireless controller pack (e.g. here) which basically replaces the existing CM927

- Electronic TRVs (e.g. pack of 4)

Have a look at the thread I linked above, the scenario is very similar to yours. You'll find that the installation instructions have their limitations, but there are some amazing people on this forum who I cannot praise enough. I couldn't have figured out some (probably fairly basic) questions without them.

Good luck

Martin

Well, one of the first things Honeywell support asks you when there's a potential BDR problems is the code on the unit so they can identify how old it is.

And I'm also inferring from comments posted here by the Honeywell guys. But of course, like most things Evohome, there's no way of knowing for sure....

Wow, thank you all so much for your information. If I have to use new BDR is it difficult to fit,I have limited electrical knowledge..cheers again..

[DBMandrake]

Wow, thank you all so much for your information. If I have to use new BDR is it difficult to fit,I have limited electrical knowledge..cheers again..

If you have an old BDR91 already wired in correctly you could just swap the front plates over - the rear plate has the terminal block that has the wiring and the front half has the electronics in it. Doing so would be equivalent to swapping the whole thing over from a wiring point of view without actually touching the wires. (Make sure you turn off the power to the heating at the switchboard before opening it of course)

I think you'll be fine with the old one but if you did need to swap it swapping the front plates would be an easy no-wiring approach.