How to integrate Daikin Altherma LT heat pump?

(John Cocula) #1

Hello all,

I had originally intended to use and rework the Daikin binding for use with my new Daikin Altherma low-temperature split air-to-water heat pump, but on further inspection it seems as if that binding is only for air conditioners. That binding integrates to either the KKRP01A or BRP072A42 units, which only seem compatible with a list of Daikin’s AC units.

Does anyone have experience or advice on the most sound way to integrate Daikin Altherma LT heat pumps? I’ve seen a somewhat expensive KNX module which I would rather avoid, even though the point at which it ties into the unit seems sensible (in the place of an additional controller using the P1P2 interface). There is also the CoolLinkNet unit, but only one of my indoor/outdoor models are listed as supported, and I have had no reply to my enquiry.

My specific Daikin Altherma models are:
EHVH11S26CB9W (indoor unit)
ERLQ011CV3 (outdoor unit)

Thanks for any suggestions!


(George Erhan) #2

Dear John,

The only quick solution (although seems expensive, is cheap compared to the other options - the full official list of interfaces for controlling Daikin products is here) you can have is the KNX interface.
I would go for the KNX interface only if I had a KNX bus already installed. There is also a Modbus option for Altherma here.

Best regards,


(John Cocula) #3

Thank you very much, George. If I had a KNX bus already in place, I would buy that unit since it seems well executed. The Modbus option is unfortunately only for HT (high temperature) units.

(George Erhan) #4

Is there any way you can enquire Daikin if it works for the HT also? It seems that both are using the same P1P2 interface. I don’t think that there is a difference in terms of communication. The objects should be the same. I will ask someone from Daikin and will come back. To my knowledge the HT is different only in terms of water temperature supplied (additional compressor).

(John Cocula) #5

I wish I knew a good path to get the question to someone knowledgeable at Daikin. My local Daikin installer is unlikely to know more than me on that subject. I see in the installation manual for RTD-W that its setpoint range is 25-80C, so it makes me wonder if it would be “dangerous” to try it. But you might be right in your theory that it would work, since the comms are the same. I also don’t see Modbus registers for reading back the sensor values like leaving water temperature, outside temperature, etc. I hope my only option isn’t setting up a KNX network…

Thanks for being incredibly helpful, George!

(George Erhan) #6

Dear John,

In the installation manual of the Modbus interface at page 10 are the registers you require. Manual here.
I just hang up with a Daikin Technician (service guy from Daikin directly, not dealer), he said it should work and promised he will further investigate at Daikin’s HQ. I’ll keep you updated.
It’s definitely easier to have rs485 installed! Forget about KNX just for one interface (been there done that! :wink:)
LATER EDIT: the guy called me back. The answer is that for older CA models the modbus interface works. For the one that you have EHVH11S26CB9W it does not. The only option they support is KNX. But in 2017 they plan to issue a LAN adapter for your model. Sorry for the bad news!


(John Cocula) #7

Sorry; I missed that!

That’s actually great news! I would rather wait until next year for a proper TCP/IP-based solution than either spend on a KNX setup I would under-use, or think that there is only a dead end.

Thank you again, George, for your incredible assistance.


(Jiří Herzig) #8

John, how does it go with that TCP/IP solution? Does it exist? I have Altherma HTemp and want to integrate it to OH2. Any idea? Thanks

(John Cocula) #9

Hi Jiří, I located in March and still have it on my to-do list to purchase and install a BRP069A62 for my low-temp Daikin Altherma split system heat pump. This might not be the correct device for your heat pump, not sure. IIRC the interfacing looked achievable with the HTTP binding and a REGEX or JSONPATH transformation filter. I would have to actually purchase and install the device first in order to give useful advice, but in any case it looked simple to integrate with.


(George Erhan) #10

So, it’s finally out on the market (glad to hear that)!
I have already integrated BRP069BXX and BRP069AXX. No JSON needed, just plain REGEX.
Unfortunately, Daikin does not provide support for the API.
I have managed to discover 2 main areas of these interfaces:




For both, you will need get requests. What is important is that you will need to figure out the MANDATORY order and the minimum number of the parameters to be sent in case of trying to control.
The output of such a GET request is something like:


Good luck!

(Luis Lamich Arocas) #11

Hello George,

I have a BRP069A61 recently installed in my Altherma 3. I have contacted Daikin and they have replied that they only support the APP, and that they do not give any kind of information, since it is a proprietary protocol.
I have tried with
http: // DAIKIN_IP / aircon / get_sensor_info

http: // DAIKIN_IP / aircon / get_control_info

But the BRP069A61 replies: Sorry, the requested file does not exist on this server.

I suppose there must be differences between each type of module …
How did you find out how the module works? I say it to be able to do with mine …

Thanks and best regards

(George Erhan) #12

“Man in the middle method”, use a packet sniffer and a port mirror! With Altherma the aircon section might not exist.
Sniff the packets sent between the app and the interface!

(Edouard Regis) #13

I have an Altherma LT CB series and a BRP069A2 and want to monitor it like you.

Have you suceeded to make some GET request ? I sniff the packet, but nothing obvious about the sensors values appear…the area of Georges are not accessible too.


(Kra) #14

If HTTP GET does not work for you, you need to use websocket. See: