Product detailed description
What the Buderus MX400 mixing control module does
In larger heating systems, where several heating circuits with different temperature requirements are connected to a single heat source (for example a Logamax or Logano condensing boiler) – typically underfloor heating requiring a lower flow water temperature of around 30–40 °C and a radiator circuit requiring a higher temperature of around 50–70 °C – it is not enough to control just one shared circuit. Each such circuit needs its own mixing valve and its own control module, which independently mixes hot water from the boiler with the (cooler) return water from the circuit so that the temperature at the inlet of that circuit is exactly what is needed based on the current heat demand and the set weather-compensated heating curve.
The MX400 module is exactly this kind of expansion module for a mixing circuit within the Buderus Logamatic control system. It communicates over the EMS bus with the boiler's main controller and with the room controller, measures the supply water temperature using a sensor, controls the circulation pump of the given circuit, and operates the mixing valve actuator so that the resulting temperature precisely matches the needs of a particular heating zone. This makes it possible to connect several circuits with different characteristics to a single heat source (for example underfloor heating on the ground floor and radiators upstairs) and operate each of them at its optimal temperature, saving energy and increasing living comfort.
Difference between set configurations
The MX400 module is always supplied together with a room controller, which serves as the higher-level control unit and user interface of the entire system. Buderus offers two different sets, depending on the level of control and communication method the customer needs.
Set MX400, white is a combination of the MX400 module with the Logamatic RC310 controller in white. The RC310 is a comfort wired room controller with a color touchscreen display, offering advanced heating circuit settings, weekly time programs, graphical display of temperature trends, and the ability to connect to a home WiFi network and control remotely via a mobile app. This configuration is especially suitable where wiring between the boiler room and living space is already installed or planned, and where the customer will appreciate a full-featured touchscreen display directly on the wall in the main living area.
Since the RC310 serves as the main control panel of the system, this set is typically chosen as the household's primary controller, while the MX400 module at the boiler adds a separate, independently controlled mixing circuit (for example underfloor heating) that runs with its own weather-compensated heating curve, different from the main circuit.
What's included in the set
- Logamatic RC310, white (7738112369) – 1 pc
- MX400 module (7738113982) – 1 pc
Typical use cases
The MX400 module is most often used in new buildings and renovations combining underfloor heating with radiators, in houses with an extension or attic added later to the original heating system, or in systems where it is necessary to independently control the temperature in a pool heating circuit, ventilation system, or other specific heat consumer separate from the house's main heating circuit.
Thanks to the modular architecture of the Logamatic system, it is possible to start with a simple single-zone solution and add the MX400 module at any later point, once the need for a separately controlled zone arises – for example when finishing an attic or converting a garage into living space. We recommend having the module installed and connected to the system by an authorized Buderus service technician, who will also configure the appropriate weather-compensated heating curve and mixing circuit parameters according to the type of heating elements in that zone.
Frequently Asked Questions
Can I connect the MX400 module to any Buderus boiler?
The MX400 module is designed for systems with an EMS communication bus (EMS 2 / EMS plus), used by modern Buderus Logamax and Logano boilers with Logamatic control. Before purchasing, we recommend checking compatibility with the specific type and year of manufacture of your boiler, or consulting with an installation company.
How many mixing circuits can I create this way?
The Logamatic system allows several MX400 modules to be connected, each for a separate mixing circuit – the exact maximum number depends on the specific main boiler control unit, so we recommend consulting a technician when designing a system with multiple heating zones.
Do I also need to purchase a temperature sensor and valve actuator for the MX400?
Yes, for full functionality of the mixing circuit, besides the MX400 module you also need a supply temperature sensor and a motorized actuator for a three-way or four-way mixing valve – these components are not included in this package, and it is advisable to order them together with the set if they are not already installed in the system.
What is the difference between RC310 and RC120RF in terms of comfort?
The RC310 offers a color touchscreen display, internet connection and mobile app, advanced programming, and graphical temperature history overviews. The RC120RF is a simpler wireless controller without internet connectivity, focused on basic time and temperature control, with the advantage of a completely cable-free installation.
Can I later switch from RC120RF to RC310, or vice versa?
Controllers can be replaced within the Logamatic system, but keep in mind that the RC310 requires a wired connection (or a communication module), while the RC120RF works wirelessly – so switching may require additional cabling to be installed, or removed in the opposite direction.
Does the MX400 module require its own power supply?
Yes, the module is connected to a power supply and also to the EMS bus toward the boiler – the exact wiring and placement (usually in a distribution box near the boiler or in a separate mounting box) is determined by the project documentation or the installation technician.
Warranty
Buderus products are covered by a warranty under the seller's general terms and conditions and the warranty terms of the manufacturer, Bosch Thermotechnik GmbH. You can find the exact warranty period and terms of application in the warranty documentation supplied with the product, or request them from our customer service before purchase.
