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I N S T R U C T I O N S

© 2015 OJ Electronics A/S

 

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Intelligent Room Sensor - Wired

English

Product programme

REH TA3  Room sensor with temperature adjustment

REH TM3  Room sensor with temperature adjustment and mode switch (Auto, 

Day, Night, Frost Protection)

REH TD3  Room sensor with temperature adjustment, mode switch (Auto, Day, 

Night, Frost Protection) and floor limit sensor

Mounting of sensor (figs 1 and 2)

The unit is used for comfort temperature control in rooms. The unit should 

be mounted on an internal wall approx. 1.4-1.7 metres above the floor in 

such a way as to allow free air circulation around it. Draughts and direct 

sunlight or other heat sources must be avoided.

Fig. 1 Removing the front cover

     BR 1026A11a

Fig. 2

     BR1026A01a

Room sensors - bus connection (figs 3 and 4)

Only REHAU units which are suitable for two-wire communication can be used. 

Standard installation cable of minimum 2 x 0.25 mm² can be used. Units can 

be connected in conventional star formation or in bus mode (daisy chain). The 

master has four sets of terminals marked SENSOR/CONTROLLER BUS that can be 

used for connecting the 2-core signal cable from the unit.

Any unit can be connected to any pair of terminals. The total length of 

the 2-wire system can be up to 300 m with a maximum length of 100 m 

between any two units. For further information see the table below.

Remember to c to + and – to – .

67338 02/15 (HKT)

• English

Fig. 3 Sensors connected in star formation

     BR935A03A

Fig. 4 Sensors connected in bus mode (daisy chain)

     BR935A03A

Setting up which room sensor is paired with which thermal actuator 

(fig. 5)

Each unit can be set to operate a specific output which in turn controls a 

thermal actuator on the manifold. A selector can be accessed under the 

front cover of the unit where the number of its output (i.e. its channel no.) 

can be set with a screwdriver.

Please note that channels 10 to 14 are marked as A through E on the 

selector.

A unit set to CH1 will activate the thermal actuator connected to output 1 

on the master. The channel number can be set before power is connected 

to the system.

The channel set on the unit can be subsequently changed if needed. 

If two units are placed in the same room and set to the same channel, 

temperature will be controlled by the average of the temperature recorded 

by both units.

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