Hello everybody,
For a few months I have been reading this forum with very good tips and help. My German is not very good so I will write in English.
I have a Jung room controller and a non-KNX floor heating system in combination with a central heating system. In stock I have a ABB US/U 2.2 with a relay to control the central heating system to open and close the input to request heat, and a KNX actuator to open and close the floor heating valves. The situation right now is that the floor heating system is not coupled to my KNX system do to a few questions that I have that are not jet answered.
At the moment a Honeywell thermostat controls my floor heating actuator, which opens the valves when heat is requested and sends a closed signal to my central heating system which in turn heats the water and activates the pump. After the room is at the right temperature the Honeywell opens the circuit, the central heating system stops producing hot water and the valves close.
If I connect all my EIB equipment according to the KNX specification the PWM value from my room controller opens the valves and the heating message controls the central heating. In this case there is a possibility that the central heating system (and pump) are activated while the valves are closed which is not what it is supposed to do. What I thought of as a solution is to let the heating message open and close the valves and to command heat from the central heating with the continuous PWM value and a PWM cycle time of 30 minutes. But in this case the central heating system can still be activated (due to the 30 minute lag) while the valves are closed. I can use the status from the US/U 2.2 to see if it still requests heat and leave the valves open until it too has a open circuit, therefore if the central heating system produces heat the valves are always open.
Another thing I thought of is to use the relay to control the floor heating actuator, instead of the Honeywell controller, and let the actuator do all the commanding of valves and heat requests.
All of this seems a bit much to me, especially when this is supposed to be very easy and transparent.
So I am wondering: is there a simpler and more effecient way to use KNX to control the system?
My equipment: Jung 4093KRMTSD, ABB US/U 2.2 with ER/U1.1 relay and an ABB SA/S 8.10.1 10A switch actuator.
Thank you very much for your help and insights.
For a few months I have been reading this forum with very good tips and help. My German is not very good so I will write in English.
I have a Jung room controller and a non-KNX floor heating system in combination with a central heating system. In stock I have a ABB US/U 2.2 with a relay to control the central heating system to open and close the input to request heat, and a KNX actuator to open and close the floor heating valves. The situation right now is that the floor heating system is not coupled to my KNX system do to a few questions that I have that are not jet answered.
At the moment a Honeywell thermostat controls my floor heating actuator, which opens the valves when heat is requested and sends a closed signal to my central heating system which in turn heats the water and activates the pump. After the room is at the right temperature the Honeywell opens the circuit, the central heating system stops producing hot water and the valves close.
If I connect all my EIB equipment according to the KNX specification the PWM value from my room controller opens the valves and the heating message controls the central heating. In this case there is a possibility that the central heating system (and pump) are activated while the valves are closed which is not what it is supposed to do. What I thought of as a solution is to let the heating message open and close the valves and to command heat from the central heating with the continuous PWM value and a PWM cycle time of 30 minutes. But in this case the central heating system can still be activated (due to the 30 minute lag) while the valves are closed. I can use the status from the US/U 2.2 to see if it still requests heat and leave the valves open until it too has a open circuit, therefore if the central heating system produces heat the valves are always open.
Another thing I thought of is to use the relay to control the floor heating actuator, instead of the Honeywell controller, and let the actuator do all the commanding of valves and heat requests.
All of this seems a bit much to me, especially when this is supposed to be very easy and transparent.
So I am wondering: is there a simpler and more effecient way to use KNX to control the system?
My equipment: Jung 4093KRMTSD, ABB US/U 2.2 with ER/U1.1 relay and an ABB SA/S 8.10.1 10A switch actuator.
Thank you very much for your help and insights.