Does the BTH-RA need a Bosch Smart Home Controller?

No. It is a Zigbee 3.0 device and joins the Gateway’s Zigbee network directly with its install code. The Bosch app and cloud are not involved when Edge controls it.

Where is the install code?

In the QR code under the battery cover, and on the sticker Bosch supplies with the thermostat. Keep the sticker with the site records in case the thermostat has to be paired again.

Can a room sensor control the valve?

Yes. Write the room temperature to the thermostat’s remote temperature (0 to 35 °C) and refresh it at least every 30 minutes. If the updates stop, the thermostat goes back to its own sensor.

How do I reset it to factory settings?

Remove one battery, then refit it while holding the button until the LED flashes orange quickly and RES appears. Release briefly, then hold again until the LED lights green. The thermostat restarts.

Bosch BTH-RA Zigbee radiator thermostat

Compatibility

Compatible with EpiSensor Edge over Zigbee.

Pair it with the Zigbee radio on an EpiSensor Gateway. Edge reads it locally on the Gateway.

Edge reads 23 values from it, listed under Interface.

Connect it with

Gateway ZGW-20
From €899 ex VAT Configure Gateway

Specifications

The BTH-RA replaces the manual head on a radiator valve. A built-in sensor measures room temperature and a motor drives the valve pin to hold the setpoint. Bosch rates it for 0 to 50 °C and 10 to 80 % humidity, IP20, and quotes a typical battery life of under two years on two AA alkaline cells.¹

Power: Battery. Two LR6 (AA) alkaline cells. Bosch quotes a typical life of under two years.¹
Type: BTH-RA¹
Radio: Zigbee 3.0, 2.4 to 2.4835 GHz¹
Maximum transmit power: 3 mW¹
Range in the open: Under 50 m¹
Setpoint range: 5 to 30 °C⁴
Calibration offset: -5 to +5 °C²
Valve connection: M30 × 1.5 mm¹
Adapters in the box: Danfoss RA and Danfoss RAVL³
Ambient temperature: 0 to 50 °C¹
Humidity: 10 to 80 %¹
Protection: IP20¹
Dimensions (W × H × D): 51 × 51 × 87 mm¹
Weight: 135 g without batteries¹
Maximum consumption: 220 mA, under 0.8 W¹

Where it is used

Room-level heating setpoints and schedules in small offices and meeting rooms with wet radiators, with the room temperature logged beside them.
Indoor environmental monitoring
Seeing which rooms demand heat out of hours by trending heating demand beside the boiler or heat pump’s energy use.
HVAC energy monitoring for commercial buildings
Turning heating down while a room is ventilated, with the head’s open-window detection switched on from Edge.

Interface

Readings and settings, with units and ranges where Bosch publishes them. readable, readable and writable, writable only.

Download

Reading	Unit	Range or values	Access
Measurements 7
Climate	-	-	Read only
Local temperature	°C	-	Read only
Running state	-	`idleheat`	Read only
Setpoint change source	-	`manualscheduleexternally`	Read only
Valve adapt status	-	`noneready_to_calibratecalibration_in_progresserrorsuccess`	Read only
Automatic valve adapt	-	Binary state	Read only
Error state	-	-	Read only
Controls 2
Occupied heating setpoint	°C	5 to 30 °C	Read and write
System mode	-	`heat`	Read and write
Settings 12
Local temperature calibration	°C	-5 to 5 °C	Read and write
Pi heating demand	%	0 to 100 %	Read and write
Operating mode	-	`schedulemanualpause`	Read and write
Window detection	-	Binary state	Read and write
Boost heating	-	Binary state	Read and write
Remote temperature	°C	0 to 35 °C	Read and write
Child lock	-	Binary state	Read and write
Display brightness	%	0 to 100 %	Read and write
Display switch on duration	s	5 to 30 s	Read and write
Display orientation	-	`standard_arrangementrotated_by_180_degrees`	Read and write
Displayed temperature	-	`set_temperaturemeasured_temperature`	Read and write
Valve adapt process	-	`adapt`	Write only
Diagnostics 2
Battery	%	0 to 100 %	Read only
Battery low	-	Binary state	Read only

Heating demand (pi_heating_demand, 0 to 100 %) is the valve opening. It is the point to trend when you want to know which rooms are calling for heat.⁴

When a remote temperature is written, it has to be refreshed at least every 30 minutes. Without it the head falls back to its internal sensor.⁴

Operating mode is Bosch’s own setting (schedule, manual or pause) and sits beside the standard system mode.⁴

Setup

Have the install code ready
The thermostat joins with a Zigbee install code. It is in the QR code under the battery cover. The Gateway’s Zigbee network needs that code before it will accept the thermostat.⁴
Put it into Zigbee pairing mode
Insert the batteries. The status LED flashes orange every 1.5 seconds while it is ready to pair over Zigbee, for 3 minutes. On the [+M] version the LED flashes blue at first: hold the button for more than 5 seconds until it flashes orange.²
Open pairing in Edge
Open pairing on the Gateway’s Zigbee network in Edge. The LED flashes green once when the thermostat has joined and red once if it has not. After a failure, reset it to factory settings and try again.²
Fit it and calibrate the valve
Fit the correct adapter, then screw the head onto the valve by hand while holding it in the orientation you want. Press the button to start the valve calibration and wait until the room temperature is displayed.²
Check one reading
Confirm that Edge identifies it as Bosch BTH-RA. Raise the setpoint from Edge and check that the heating demand rises, then compare the room temperature with a reference thermometer.

Common questions

Does the BTH-RA need a Bosch Smart Home Controller?: No. It is a Zigbee 3.0 device and joins the Gateway’s Zigbee network directly with its install code. The Bosch app and cloud are not involved when Edge controls it.^1, 4
Where is the install code?: In the QR code under the battery cover, and on the sticker Bosch supplies with the thermostat. Keep the sticker with the site records in case the thermostat has to be paired again.^2, 4
Can a room sensor control the valve?: Yes. Write the room temperature to the thermostat’s remote temperature (0 to 35 °C) and refresh it at least every 30 minutes. If the updates stop, the thermostat goes back to its own sensor.⁴
How do I reset it to factory settings?: Remove one battery, then refit it while holding the button until the LED flashes orange quickly and RES appears. Release briefly, then hold again until the LED lights green. The thermostat restarts.¹

Related devices

Sources

Radiator thermostat II quick instructions (BTH-RA) (opens in a new tab) (PDF) Bosch Smart Home
Radiator thermostat II [+M] user manual (BTH-RAD) (opens in a new tab) Bosch Smart Home
Radiator valves and adapter recommendations (TRV AA, BTH-RA, BTH-RAD) (opens in a new tab) Bosch Smart Home
Bosch BTH-RA device documentation (opens in a new tab) Zigbee2MQTT
Bosch BTH-RA Zigbee definition (opens in a new tab) zigbee-herdsman-converters · v26.111.0

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