Best radiator thermostat for FRITZ!Box - Smart Thermo 302 and valve adapters

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Best radiator thermostat for FRITZ!Box?

For a FRITZ!Box router, it is best to choose the dedicated FRITZ!Smart Thermo 302 radiator control, previously known as FRITZ!DECT 302. This is an official device from the manufacturer that connects directly to your router without the need to purchase any additional gateways or bridges.

To operate, you need a FRITZ!Box router with a built-in DECT base station and FRITZ!OS version 6.83 or higher. Just keep in mind that two older router models, namely 7312 and 7412, do not support this solution.

The radiator control uses the DECT ULE standard, providing an indoor range of up to 40 meters. The device is powered by three AA batteries included in the factory packaging, and a clear e-paper display makes reading the parameters easy.

Fun fact: The FRITZ!DECT 302 model officially debuted at MWC 2022 as an updated successor to the manufacturer's earlier radiator controls.

How to check your radiator valve and choose an adapter

Before purchasing, check the thread on your radiator by removing the old thermostatic head. Most common radiator valves in our homes feature an M30 x 1.5 thread, onto which you can screw the FRITZ!Smart Thermo 302 controller directly without any adapters.

You will find this M30 x 1.5 standard on valves from brands such as Heimeier, Honeywell, Junkers, Landis+Gyr, MNG, Zehnder, and newer Oventrop models, among others. Simply unscrew the old controller and screw the FRITZ! device into its place.

If you have a Danfoss RA valve with a diameter of 20 or 23 mm in your home, you will find the matching adapter included in the box with the controller. It is different for other versions from this manufacturer, such as the 34 mm Danfoss RAV with a separate pin or the 25.5 mm Danfoss RAVL, for which you need to purchase an adapter separately.

You will also need an additional adapter for Giacomini valves with a diameter of 22.6 mm, Vaillant with a diameter of 30.5 mm, older Oventrop valves with an M30 x 1.0 thread, and M28 x 1.5 threads from Herz, Comap, and Pettinaroli.

Below, we have compiled a list of proven products and accessories to help you quickly assemble a working heating control system.

Recommended thermostats and accessories for FRITZ!Box

How many radiator controls to buy and which accessories to choose

The rule is simple: you need exactly one control for each radiator you want to manage. If you have two or three radiators in a single large room, you can link them into a group in the FRITZ!Box system, so they heat at the same target temperature.

Although the radiator control can detect a temperature drop when a window is opened on its own, it is worth considering the FRITZ!Smart Control 350 magnetic opening sensor. The control can detect an open window by itself or via such a sensor, ensuring the radiator turns down more reliably while airing out the room.

A convenient addition is the wireless FRITZ!DECT 440 switch with four buttons, which you can place on a table or mount on a wall. It allows you to adjust the temperature or start heating without reaching for your phone or logging into the router panel.

If you live in a large multi-story house or the radiators in the basement lose connection to the router through thick ceilings, the FRITZ!DECT Repeater 100 signal repeater will come in handy. You simply plug it into a power outlet halfway between the router and the distant room.

Installation and control: what to look out for before the heating season

Keep in mind that the FRITZ!Smart Thermo 302 operates in a temperature range from 0 to 50 degrees Celsius, and the manufacturer explicitly states that it is not intended for damp rooms. For this reason, avoid installing it in small, poorly ventilated bathrooms or directly over a bathtub.

When looking for the device in online stores like Amazon, you might come across two different names: FRITZ!DECT 302 and FRITZ!Smart Thermo 302. It is the exact same physical product, and you can safely choose the version with the older designation.

Fun fact: The name change from FRITZ!DECT to FRITZ!Smart came with a software update, and the radiator control itself remained unchanged.

Once installed, you get extensive configuration options in the FRITZ!App Smart Home, on a FRITZ!Fon cordless phone, or in a web browser. You can set a schedule with up to 8 switching points per day, a vacation mode, a boost function for rapid heating, as well as automatic frost protection and valve calcification protection.

Questions and answers

Is the FRITZ!Smart Thermo 302 the same as the FRITZ!DECT 302?

Yes, it is the exact same device. The FRITZ! manufacturer phased out the DECT term in the names of its smart home accessories in favor of FRITZ!Smart, introducing this change via a software update. On the market and in online stores, this control still appears under both names.

Which FRITZ!Box is needed for the FRITZ! thermostat?

Any FRITZ!Box router model with a built-in DECT base station and FRITZ!OS version 6.83 or newer is required. Only two specific older router models are excluded from support: the FRITZ!Box 7312 and FRITZ!Box 7412.

Does the FRITZ! thermostat fit Danfoss valves?

Yes, it fits, but the mounting type depends on the specific type of Danfoss valve. An adapter for the popular Danfoss RA valves with a diameter of 20 or 23 mm is included in the box with the radiator control. For less common Danfoss RAV and RAVL valves, you need to purchase a dedicated adapter separately.

Is a gateway required for the FRITZ! thermostat?

No, an additional gateway or external bridge is not needed. The radiator control connects directly to your FRITZ!Box router using the built-in wireless base station via the energy-efficient DECT ULE standard.

What is the range of the FRITZ! thermostat from the FRITZ!Box?

The DECT wireless range indoors is up to 40 meters from the router. In larger homes or with thick walls, the range can be extended using the FRITZ!DECT Repeater 100 signal repeater.

Sources

• FRITZ!: Which radiator valves can the FRITZ! radiator control be used with? - manufacturer page (uk.fritz.com)
• Notebookcheck: AVM launches new smart radiator controller, the FRITZ!DECT 302 - industry article (notebookcheck.net)
• Basic Tutorials: AVM FRITZ!DECT 301 in test - industry article (basic-tutorials.com)
• Mighty Gadget: FRITZ!Box 7690 Wi-Fi 7 router review - industry article (mightygadget.com)
• Netzwelt: AVM renames FRITZ!DECT devices to FRITZ!Smart - industry article (netzwelt.de)