[SOLVED] Adding KNX HVAC valve to knx.things (to start the AC cooling unit)

Hi all,
Few weeks ago I asked about help with getting started on knx and openhab, to take control of the knx apartment for which I dont have any documentation whatsoever.
I love the community and openHAB, it’s been great so far and I’m controlling all the lights in the apartment and reading the temperatures in the rooms. I managed to pinpoint all the lights by monitoring the bus and pressing the buttons.

However, I can’t seem to activate my AC, been trying with different options in the config to no avail.

It is a central district cooling system, so I just need to open valve and fan starts blowing cold air.
I managed to configure temperature control (I can set the temperature) and I can enable AUTO mode, but I cannot start or stop the AC which is the most interesting part :slight_smile:

So the behaviour:
When I press AC on button, it sends “26%” to the bus address 1/5/48 and then immediately after there is something like “35%” coming on 1/5/49
If you press it again(more speed to the fan), it sends 53% and reads 70% on the 1/5/49, if you press again (3rd speed to the fan) it send 79% and it reads 100% on the 1/5/49. If you press AC OFF it sends 0% and reads 0% to both addresses.

my knx.things:
Type switch : Dressing “Light” [ ga=“1/5/4+<1/5/5” ]
Type switch : Bedroom “Light” [ ga=“1/5/1+<1/5/3” ]
Type number : ACLiving1 “Humidity” [ ga=“1/5/48+<1/5/49” ]
Type number : ACLiving2 “Temperature” [ ga=“1/5/45+<1/5/53” ]
Type switch : ACLiving3 “Mode” [ ga=“1/5/46+<1/5/47” ]
Type number : LivingTemp “Temperature” [ ga=“9.001:<1/5/44” ]
Type number : KidsTemp “Temperature” [ ga=“9.001:<1/5/53” ]

(ACLiving1 does not work, setting the temperature and auto mode works)

my knx.items:
Switch KidsRoom “KidsRoom [%s]” { channel=“knx:device:bridge:generic:KidsRoom” }
Switch Dressing “Dressing [%s]” { channel=“knx:device:bridge:generic:Dressing” }
Switch Bedroom “Bedroom [%s]” { channel=“knx:device:bridge:generic:Bedroom” }
Number ACLiving1 “ACLiving1 [%d %%]” { channel=“knx:device:bridge:generic:ACLiving1” }
Number ACLiving2 “ACLiving2 [%.1f °C]” { channel=“knx:device:bridge:generic:ACLiving2” }
Switch ACLiving3 “ACLiving3 [%s]” { channel=“knx:device:bridge:generic:ACLiving3” }
Number LivingTemp “LivingRoom [%.1f °C]” { channel=“knx:device:bridge:generic:LivingTemp” }
Number KidsTemp “KidsRoom [%.1f °C]” { channel=“knx:device:bridge:generic:KidsTemp” }

here I played with different options, tried dimmer, etc…tried to read the values with 5.001 DPT but did not succeed.

my sitemap:
Text item=LivingTemp
Slider item=ACLiving1 //mappings=[0=“0%”,26=“26%”,53=“53”,79=“79”]
Setpoint item=ACLiving2
Switch item=ACLiving3
Frame label=“Hall” {
Switch item=Entrance
Switch item=Foyer
Switch item=Corridor

Please suggest any steps I might take to investigate it more, how to find which DPT is required, what logs to check, what options to play with in the config…
so I basically need to succeed in send “26%” to 1/5/48 to start the AC, and “0%” to stop it.

thanks in advance!


Just because you see the HVAC reporting what seems to be fan speed, does not mean you can send it the same data.
It’s more likely you have to send something like 0 or 1 or 2 etc, as commands. But who knows where to.

People might come up with suggestions, if you can provide any brand names or model numbers.

So you are saying its possible that by monitoring the bus I cannot see what was actually sent by actuator to the fan or valve unit? Bummer…

If I want to attempt to send 0 or 1 can I define it as a regular switch and just give it a go with on/off ?
(edit: I have tried it, and you are right. by defining it as a switch and turning it ON it started blowing full speed, but I cannot turn it off via the same switch button…and the numbers on the bus are 0% to 1/5/48 and 100% to1/5/49, strange… and another bad thing is that it did not illuminate the LED on the wall controller for AC ON, like it does when I control lights from openhab.
just tell me, can I do some damage to this hvac system by playing like this? )

Unfortunately, the units are not visible, I just have a big grill on the wall from where air is coming from, nothing is visible. there is a lowered ceiling with a small door to access valves, clean the filter etc but no model numbers there.
And the wall controllers are not from the AC manufacturer, it’s a knx installation so all wall units control lights, dimmers and hvac.

If it will be any help to anyone who might be familiar with Dubai,Middle East region, I’m located in Abu Dhabi, and this is typical style of building in the middle east, centralized air conditioning…so maybe someone knows what units could be…
I have seen here in this country but in non KNX apartments wall controllers for the same HVAC units are often Honeywell…


No idea. Didn’t know what you are monitoring. Now it is emerging that the button being pressed is actually a remote wall panel, and not a physical button on the the HVAC things are looking better :smiley:

I would guess your two addresses are different devices; from openHABs view you would want to separate the panel and the HVAC, with the panel as one of the binding’s xxx-control types. When it is figured out, this should allow for commands from openHAB to also update the display at the panel, if you can figure the target
That’s all beyond my skills, though.

I’d be playing with a dimmer type channel to try and match up to you % fan speed.

uff, this hvac is more complex than I imagined. when carefully monitoring, there is 6 addresses involved!

to summarize:
1/5/48 - receives 26% when ON, 0% when OFF, 53% and 79% when adjusting the speed
1/5/49 - receives 35%,0%, 70%,100% respectively
1/5/37 - receives 1% when OFF
1/5/45 - receives temperature by 0.5 increments when set, when OFF, receives some high number like 34 (like its set to 34C so its off)
1/5/53 - receives temperature by 0.5 increments when set (and keeps receiving it periodically)
1/5/50 - when OFF keeps receiving “0” periodically, when ON receives some negative number like -3445

So I should probably define them as 6 separate devices and play with it…I’m afraid KNX not only controls the fan speed, it controls the valve that needs to open, I hope I won’t blow it by fiddling :slight_smile:


Found the device, Woertz 49552 Fan Coil Actuator, but I dont know how to integrate it to openhab, found some posts about merten fan coil actuators…

solved - configured as dimmer