Danfoss
Danish HVAC engineering — the actuators and valves behind KNX floor heating across Europe.
Danfoss (Nordborg, Denmark — founded 1933) is one of the world's largest HVAC component manufacturers. In European residential and commercial buildings, Danfoss floor heating actuators, pressure-independent valves (AB-QM, AB-PM), and manifold systems are found in millions of installations. While Danfoss does not manufacture KNX devices, their 24V electro-thermal actuators are the load that KNX 24V output actuators (MDT, Hager, ABB) switch — making Danfoss a key component in every KNX heating panel.
Role in our panels
How we use Danfoss
Danfoss products relevant to KNX building automation: TWA-A 24V AC electro-thermal actuators for floor heating manifolds (normally-closed, 2W, M30×1.5 thread), AB-QM and AB-PM pressure-independent balancing and control valves for hydronic balancing, ECL comfort controllers for district heating substations (Modbus TCP interface), Danfoss Icon WiFi thermostat system for simpler installations, and Danfoss Ally Zigbee TRVs for radiator control.
In our panels, Danfoss TWA-A actuators are the end-load driven by KNX 24V output actuators (MDT AKU-1616.03, Hager TXA212B). One KNX actuator output = one Danfoss TWA-A = one floor heating zone. For commercial HVAC: Danfoss ECL comfort controllers connect to KNX via Modbus TCP gateway — the KNX system reads heat meter data and sends setpoint commands to the ECL. For district heating (Latvia, Lithuania, Estonia common): ECL 110/210/300 Modbus interface is the standard integration path.
Used in these project types
Danfoss products
Key components we install
TWA-A 24V Electro-Thermal Actuator
Standard normally-closed (NC) electro-thermal actuator for Danfoss and Uponor manifolds. 24V AC, M30×1.5 thread. Opens when energised, closes when de-energised. 2W power consumption. Quiet operation (no motor click). Used on virtually all EU floor heating manifolds controlled by KNX 24V actuators.
TWA-A 230V Electro-Thermal Actuator
Same as TWA-A but 230V AC for legacy 230V installations. Less common in new build — 24V is preferred for safety. Compatible with 230V output actuators. NC operation.
AB-QM DN15 Pressure-Independent Valve
Pressure-independent combined balancing and control valve (PICV). Maintains constant flow regardless of system pressure fluctuations. Essential in large hydronic systems to prevent over-flow in zones near the pump. Pre-settable flow rate 0.02–0.30 m³/h.
ECL Comfort 210 Controller
Advanced heating and cooling controller for district heating substations and heat exchangers. Modbus RTU/TCP interface. Controls weather compensation curve, DHW priority, heat curve optimisation. Common in Baltic states district heating systems.
Icon Master Thermostat
Central controller for Danfoss Icon 24V floor heating system. Manages up to 15 zones via 24V bus between master and room modules. Not KNX — standalone Danfoss system. Simpler alternative to full KNX heating control for smaller projects.
Ally TRV (Zigbee)
Zigbee 3.0 radiator thermostatic valve. Compatible with Home Assistant via Zigbee2MQTT. For radiator control complement to KNX — integrates via HA → KNX bridge. Battery powered, 2-year life.
Danfoss FAQ
Are Danfoss TWA-A actuators compatible with Uponor and Rehau manifolds?
Yes — the M30×1.5 thread is the EU standard for floor heating actuators. Danfoss TWA-A fits Uponor, Rehau, Giacomini, and most other EU manifold brands. Verify thread before ordering — some manifolds use M28×1.5 or require an adapter ring.
How does Danfoss ECL connect to KNX?
Danfoss ECL controllers have a Modbus RTU (RS-485) or Modbus TCP interface. A KNX-Modbus gateway (e.g. MDT SCN-IP100.03 with Modbus extension, or Home Assistant via pymodbus) reads ECL temperatures, setpoints, and heating demand. KNX group addresses then publish this data to room controllers and energy dashboards.
Should I use Danfoss Icon or KNX for floor heating control?
Danfoss Icon when: budget is tight, no KNX system planned, up to 10 zones, no integration with lighting/security needed. KNX when: multi-system integration required, more than 10 zones, presence-based setback via PIR sensors, setpoint linked to security arm/disarm, or energy monitoring per zone. KNX gives far more flexibility but at higher cost.
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