Combine electrical & water underfloor heating

[NordicSmartHomes]

Hi Forum,

Is there a "best practice" way to combine water based underfloor heating with a electrical underfloor heating? Only using SpaceLogic KNX components.

My idea is to use https://www.se.com/eg/en/product/MTN6730-0002/spacelogic-knx-valve-drive-controller/ for both Electrical (with help of contactor A9C15030) and 230v valve motors for water.

The general idea is to use the electical floorheat as help to quickly heat the floor when needed and to be able to switch of water heating during summer. Preferably automatically with no input from user.

/ best regards (KNX newbie) jörgen

[Thomas_Rohde]

Hello NordicSmartHomes!
I guess there is no "best practice" as it is a pretty specific approach.
What do you mean with "Only using SpaceLogic KNX components"?
Does it mean you are looking for a solution which consists only out of real KNX-Products?
I mean no product like W4K/sL included?
Is the project still in an early phase where we are free in terms of product selection?

[NordicSmartHomes]

Hi Thomas, Thank you for your reply & involvement 🙂

I was hoping i could solve the functionality without W4K/sL, But nothing is set in stone. 

This is my planned setup for a bathroom:

- 1 dynamic label switch (room control)

- 1 MTN6003-0011 switch actuator with 33kOhm temp sensor (floor temp)

Water heat control:

- channel (A) from a Valve actuator MTN6730-0002 

- 1 Valve actuator 230v

Electrical Heat control:

- channel (B) from a Valve actuator MTN6730-0002 

- 1 Kontaktor iCT plus 20A 1P Uc 230VAC

My initial thought was that while Water heat is enough to warm the floor, the electrical underfloor heat remain turned off. But when Water heat is turned off (during summer) the electical starts.

My idea is to use either the "external heat requirement" object or the "Switch pump" object from chanel (A) to activate chanel (B).

/ Jörgen

[Thomas_Rohde]

Hello Jörgen!
I think to get it "somehow" automatic you need to work with the setting in the Valve drive controller "basic and additional heating".
This has the advantage that one controller handles both heat-sources in the correct way.
And you can let the function go simply within one device (KNX Valve Actuator).

BUT, it seems that is not what you are looking for as you want in summer the electrical one and in winter the hot water one.
What about a certain logic within W4K?!
Means you configure the room temperature controller with the settings you like for "heating".
The dedicated Group-Addresses (GA) you just link in the ETS (e.g.1/1/x).
You create a dedicated set of GAs for the hot water approach (1/2/x) and the electrical one (1/3/x).
Depending in which period of the year you are ... a logic within W4K could switch from winter to summer and forward the room-temperature-controller infos to the dedicated heating GAs (1/2/x) or (1/3/x).
With that approach you have both heating systems completely seperated.

But again, it is everything else as a best practive 😉