Daikin D2CND024A1A Gas boiler + D(R)OTROOMTHEAA Room thermostat

[mihsu81]

Hi Schelte,

I'm using the OT gateway from NodoShop (24V version with ESP8266_NODEMCU) with a Daikin D2CND024A1A Gas boiler and a D(R)OTROOMTHEAA Room thermostat.

The thermostat doesn't seem to support "Remote override room setpoint". It remains a 0.00 and the TT and TC commands don't have any effect.

However I've managed to identify some of the additional MessageIDs and collected a capabilities log file.

Would it be possible to add this functionality in the P16F88?

Thank you in advance.

[hvxl]

It looks like your capslog has already been entered into the equipment matrix. That shows that the thermostat doesn't send MsgID 9, which would be needed for the TT and TC commands to work. Possibly one of the free-to-use 128+ message IDs provides similar functionality. At least Daikin offers their own gateway that appears to be able to do this. But I currently don't have nearly enough details to implement anything special in the OTGW firmware.

[mihsu81]

Are there other logs I could collect or other tests that would give you the needed info?

[hvxl]

Unfortunately it's not as simple as that. The Test & Diagnostics area (message IDs 128 and higher) is free for equipment manufacturers to use however they want. So you would need documentation from Daikin to understand what the values mean and how to respond. Most manufacturers are not very forthcoming with such information.

It may be possible to partly reverse engineer things if you have the Daikin gateway and monitor what happens when you change the setpoint using their app. But if you had their gateway, you probably wouldn't need the OTGW for this functionality.

[mihsu81]

I do have their gateway (DRGATEWAYAA), and used it to collect the data from OpenTherm Messages Daikin.7z.
There's still more data to collect, but I wanted to make sure something can be done with it, before I spend more time on it.

Indeed the DRGATEWAYAA can be integrated with Home Assistant using websockets but the gateway just stops responding after a while (between 2 hours and 2 days).

Thank you for your time.

[hvxl]

Excellent! In that case we may be able to figure something out.

Does the Daikin app provide a way to change the thermostat setpoint? If so, can you collect a log where you change the setpoint a few times? Please note down the times when you made a change and which temperature setting you picked. Also allow enough time for each change to be picked up by the thermostat. Because the DRGATEWAYAA gets installed in the boiler, it has the same limitations to provide information to the thermostat as the OTGW: It has to wait for the thermostat to request the information.

There is close to no space left in the PIC16F88 firmware. So it won't be possible to add a dedicated feature for this. But hopefully the same effect can be achieved using the existing SR command.

[mihsu81]

Sorry, for the delay. It looks like i missed your message.

Here are my notes with the temperature changes performed from Daikin Onecta and I've also attached the logs.
It usually took between 40 and 70 seconds before the temperature or mode change would be reflected in the OT communication.

Already in Day Mode
19:44:00 set to 23.00
19:46:41 set to 22.50
19:48:12 set to 10.00
19:48:57 set to 30.00
19:49:05 set to 22.50

19:51:45 Changed to Night Mode which changed the temperature automatically to 24.
19:53:50 set to 23.50
19:54:47 set to 23.00
19:55:48 set to 10.00
19:57:10 set to 30.00
19:57:53 set to 24.00

19:59:09 Changed to Day Mode which changed the temperature automatically to 22.5.

20:00:15 Switched off Economy mode
20:01:09 Switched on Economy mode

20:02:45 Turned Off Heating which changed the set point to 05.00

20:03:57 Turned On Heating which changed the set point to 25.50

[hvxl]

It's fun to do some detective work like this. It looks to me like the thermostat does a ReadData request of MsgID 130 once a minute to allow the boiler (or OTGW) to indicate if it has any information it wants to share. Depending on which bits are set in the response, the thermostat generates ReadData requests for different message IDs:
bit 12 => MsgID 160
bit 14 => MsgID 161
bit 15 => MsgID 174

MsgID 160 ReadAck contains the desired room setpoint in f8.8 format.
MsgID 161 ReadAck contains the desired room setpoint times 10 in u16 format. In day mode bit 15 is set.
MsgID 174 ReadAck contains the desired mode:
1 = Day mode
4 = Night mode
5 = Heating off

I'm unsure what the need is to have both MsgID 160 and 161. In your log the DRGATEWAYAA only triggers MsgID 161 in day mode, but both 160 and 161 in night mode, for some unclear reason.

There are a few discrepancies in what I found compared to the information you provided in your "OpenTherm Messages Daikin" attachment in your first post.

In any case, it looks like it should be possible to recreate these messages with the OTGW using SR commands. For example if you want to change the room setpoint to 21.5 degrees in day mode, you would have to issue the following commands:
SR=161:128,215
SR=130:64,0
Then after the thermostat requests MsgID 161, you clear them again:
CR=130
CR=161

Similarly, to change to night mode:
SR=174:0,4
SR=130:128,0
And after MsgID 174 has been requested by the thermostat:
CR=130
CR=174

A short while after receiving the ReadAck of MsgID 160 and 174, the thermostat does a WriteData of the new value. It also does a WriteData of MsgID 159 when the setpoint is changed in day mode. I don't expect that these messages will cause any problems.

Once this works, it may be interesting to see what happens if you don't set the upper bit in MsgID 161 in day mode, or if you trigger only MsgID 160.

[mihsu81]

Awesome. All commands worked well.
Indeed looks like some of the info I collected is wrong, I guess I didn't wait enough to get the correct message values. MsgID 174 Off mode and MsgID 128 and maybe some of the temperature readings were wrong.

This seems to be the correct data:
MsgID 174
1 = Day mode with schedule on
2 = Night mode with schedule on
3 = Day mode with schedule of
4 = Night mode with schedule off
5 = Heating off

MsgID 128
70 = Enable Schedule Automatic 1
73 = Enable Schedule Automatic 2
65 = Disabled Schedule Night Mode On
66 = Disabled Schedule Day Mode On

MsgID 130
0 = When no incoming change and confirmed change
16384 = When changing Temperature in Day/Night Mode with Schedule On
18432 = When changing Temperature in Day Mode with Schedule Off
20480 = When changing Temperature in Night Mode with Schedule Off
32768 = When changing Day/Night Mode and Heating On/Off and Enable/Disable Schedule

I've noticed that changing the temperature with SR=161:128,215 and SR=130:64,0 changed the temperature for Day Mode and didn't change the temperature for Night Mode when I was in Night Mode.
So I guess we always have to take into account in which Mode is the Thermostat.
How do you know which data to send with MsgID 130?

[hvxl]

The SR command takes a message ID and 2 data bytes. So you have to split your 16-bit values into two 8-bit values. That's why 32768 becomes 128,0 and 16384 must be sent as 64,0.