Boiler Controller - Computherm Wireless Thermostat

[Bob B]

I installed a Computherm Q7RF http://thermostats4u.co.uk/products/computherm-q7rf wireless thermostat* a few months ago.
It works well but I want to scrap the thermostat and just use the receiver with fhem and a CUL which will also control MAX! eQ-3 heads http://www.conrad-electronic.co.uk/ce/en/product/1378424/eQ-3-MAX-Wireless-thermostat-head?ref=list.

All I know is that the receiver operates at the same frequency as the eQ3's; 868MHz.
I suspect it is a unidirectional device and does not send confirmation of its state or change of state.
I haven't been able to find any further information.

Can anyone shed any light on this for me please? Is there a generic protocol that such simple switches tend to use perhaps?
Failing that, any pointers on using the CUL to snoop with wireshark, say, would be appreciated.

Bob

* They're £30-40, "Designed in Europe, Made in China" things replete with bouncy buttons on the thermostat and a "suspicious" Omron relay in the receiver but mine works well.

[fruit]

I cannot find any information on protocols used by that device from a quick search but that doesn't man that no-one has cracked it.

MAX! eQ-3 devices use a Cube as controller by default but this can be replaced with a CUL using MAX protocols

Many manufacturers and device groups use 868MHz, others 433MHz - other regions may allow more/less and/or different frequencies.

In general each manufacturer will use their own protocol to communicate with their own devices, often encrypting as well. It is extremely unlikely that any non MAX! eQ-3 device will be able to understand MAX! eQ-3 protocol eg. HomeMatic and MAX both use 868MHz but they each use different protocols, there is no means of direct communication between the two systems.

The German http://fhem.de/Heimautomatisierung-mit-fhem.pdf contains some information on various devices and protocols at the beginning from memory.
http://www.domoticaforum.eu/viewforum.php?f=55&sid=4fe7a558c474c73075a9d21a07390eff might be a useful English resource though not fhem specific

The last link and the early posts in the fhem forum may give you some ideas about how to sniff what the device is sending/receiving - but I feel it might be easier to use an already supported device.

[Bob B]

Thank you very much for the comments and links fruit. Much appreciated.

I shall spend tomorrow  combing Domoticaforum and trying to translate the pdf.

In the last resort I'll lash up a hardwired relay. I think I saw a reference to a MAX boiler controller somewhere but it doesn't seem available to purchase anywhere; certainly not in the UK at least. It makes me wonder about the philosophy of the MAX eQ-3 kit; seems a bit lacking if you can't easily control the boiler.

... but I feel it might be easier to use an already supported device. I totally but reluctantly agree!

[fruit]

Sorry I could not find any better links describing devices and protocols but the pdf is most certailnly worth taking the time to read/translate.

I think many simply rely on the boiler sensing flow/return temperatures as control.
I have a 2 gang Homematic switch and Homematic USB adapter (the latter no longer available it seems) for boiler/pump control.

The MAX boiler controller appears to be a very recent introduction, uses MAX protocol and seems to be a programmable 2 gang time switch. See http://www.box.co.uk/EQ-3_Max!_Boiler_Control_Actuator_2_chan_2017863.html for UK seller (no idea of their reliability).

I believe there are many more district heating installations in mainland EU than UK where boiler control is not necessary. They do have switchable socket adapters in the MAX range - MAX! Zwischenstecker Funk-Steckdose

[alangward]

Hi Bob,
I cannibalised a MAX1 eq-3 "Switching Adaptor Plug" and used it to replace my conventional wall thermostat that had been controlling the heating.
However, They don't seem to be listed any more.

Alan

[Bob B]

Many thanks for helping me fruit.

>Sorry I could not find any better links describing devices and protocols but the pdf is most certailnly worth taking the time to read/translate.
Will do! I have the CUL working now and am very slowly getting to know the kind of approach that might get me a bit further.

>I think many simply rely on the boiler sensing flow/return temperatures as control.
I have a 2 gang Homematic switch and Homematic USB adapter (the latter no longer available it seems) for boiler/pump control.
Yes, I read about that on your ply.me.uk page. In fact, that page made me buy the eQ3 kit in the first place.

>The MAX boiler controller appears to be a very recent introduction, uses MAX protocol and seems to be a programmable 2 gang time switch. See http://www.box.co.uk/EQ-3_Max!_Boiler_Control_Actuator_2_chan_2017863.html for UK seller (no idea of their reliability).
Thanks for that. I got excited and then saw the price and the fact that it's out of stock so I calmed down again!

>I believe there are many more district heating installations in mainland EU than UK where boiler control is not necessary. They do have switchable socket adapters in the MAX range - MAX! Zwischenstecker Funk-Steckdose
Again, many thanks. I hadn't realised they existed.

Bob

[Bob B]

Hi Bob,
I cannibalised a MAX1 eq-3 "Switching Adaptor Plug" and used it to replace my conventional wall thermostat that had been controlling the heating.
However, They don't seem to be listed any more.

Alan

Hi Alan,

Thanks for that nice idea. I'm guessing it's the same sort of thing that fruit refers to.  I saw yesterday that you can get 2 x 13A switching adaptors complete with plugin  board for Raspberry Pi from energenie for £20 which pleasantly surprised me. At least I'm not short of options now if I can't get anywhere with the Computherm.

Bob