Manual terneo mex

Installation
and operation 
manual. Print version

In the box: thermostat, frame, temperature sensor with connected wire, installation and operation manual, the packing box

Manual

Content

Purpose

Technical data

Installation

Electrical connection diagram

Exploitation

Possible issues and solutions

Purpose

‍The thermostat terneo mex is designed to maintain a constant temperature from 10 to 40 °C in underfloor heating systems based on: electric heating cable and film; water floor heating using a normally closed electrothermal servo with an operating voltage of 230 V. Intuitive temperature control with a knob. The presence of a toggle switch allows you to turn off  the thermostat without changing the set temperature level.

Technical data

Maximum load current (for category AC-1)

16 А

Adjustment range

10...40 °С

Temperature hysteresis by floor

2 °С

Maximum power load (for category AC-1)

3 000 VА

Input voltage

230 V ±10 %

Weight in the complete set

0,17 kg ±10 %

Temperature sensor (in set)

NTC thermo-resistor 10 kOhm at 25 ° C (R10)

Length of the sensor connected cable

3 m

Maximum extension length of the temperature sensor

20 m

Number combinations under heat, at least

50 000 cycles

Number of combinations  without heating, no less than

20 000 000 cycles

Overall dimensions (w·h·d)

75 х 75 х 43 mm

Inner overall dimensions of decorative frame

45 х 45 mm

Compatibility with frames from other manufacturers

Schneider Electric Unica

Installation

‍Read this document carefully before installing and using the thermostat. This will help to avoid possible hazards, errors, and misunderstandings.

‍The thermostat is designed for indoor installation at  a height ranging from 1,4–1,6 m from the floor level. The ambient temperature during installation should be within –5...+45 °C. When installing in a bathroom, toilet, kitchen, or pool, place the thermostat in a location not exposed to accidental splashes. Minimize the risk of moisture and liquids entering the installation area.

☝️Recommendations for connecting loads more then 10 A. The terneo thermostat may not handle a current  of 16 A and could overheat in the presence of unfavorable factors such as poor heat dissipation  from the socket, high ambient temperature, or poor installation quality. We guarantee stable operation  of the thermostat with a current up to 10 A. If the current exceeds 10 A, we recommend connecting the heating cable through a contactor (magnetic starter) rated for the required current. See diagram 2.

To protect against short circuits, install an automatic circuit breaker (CB) with a rating of up to 16 A in the phase wire break before the thermostat.

To protect against electric shock, install an SSD (safety shutdown device). See diagram 1.

For installation you need:
— make a hole in the wall with a diameter of 60 mm  for the mounting box and channels for power supply and sensor wires;
— bring the heating system power and sensor wires  to the mounting box;
— make connections according to this manual;
— secure the thermostat in the mounting box.

The terminals of the thermostat are designed for wires with a cross-section of no more than 2.5 mm². It is recommended to use soft copper wire, which can be tightened in the terminals using a screw-driver with a blade width not exceeding 3 mm and a torque of  0.5 N·m.

The use of aluminum is not desirable. A screwdriver with a blade width greater than 3 mm may cause mechanical damage to the terminals, which can result in the loss of warranty service rights.

Place the sensor in the floor screed using a mounting tube, such as a 16 mm diameter metal-plastic tube, which bends once with a radius of at least 5 cm and is inserted into the heating zone for 50 cm. To ensure the sensor can be replaced in the future, seal the end of the tube with a copper plug or insulation tape. Sealing with a copper plug will provide more accurate floor temperature measurements. Insert the sensor into the tube after the screed has hardened. Strip and crimp the ends of its wire with insulated terminals.

If necessary, reduction and increasing (up to 20 m) of sensor connecting wires is acceptable. For extending, use a separate cable with a cross-section of  0,5... 0,75 mm². Near the sensor connecting wires should not be the power cables, they may be interfere.

If you purchased a heating cable and its labeling hasn't its rated power, then before connecting the thermostat (to avoid breakdown of the thermostat  due to the excess of its certified values) power (P) must to be calculated.

For this to measure the current (I) consumed of the heating cable (using the ammeter with corresponding measurement limit) and multiply by the supply voltage (U). Or to measure the resistance of the heating cable (R) with ohmmeter, divide the mains voltage (U) to the obtained resistance and multiply by the main voltage (U).

P = U × I (W)

P = U × (U / R) (W)

Figure 1.  Mounting the thermostat and underfloor heating

Electrical connection diagram

‍The temperature sensor is connected to terminals 1 and 2. Without sensor the thermostat will not work.

‍The supply voltage (230 V ± 10%, 50 Hz) is applied to terminals 5 and 6, and the phase (L) is determined by the indicator and is connected to the terminal 6, a zero (N) — on terminal 5. To the terminals 3 and 4 is connected the load (the connecting wires from the heating element).

‍Important! Install and check the load before installing and connecting the temperature controller:

make sure that the load is undamaged and free of short circuits;

check that the load resistance meets the manufacturer's specifications.

Before switching on the device, make sure that the wires are connected correctly. Failure to do so will result in damage to the thermostat.

Diagram 1.  Connecting a thermostat for heating with a two-core cable

Diagram 2.  Connecting the load via a magnetic starter

Exploitation

‍According to the data from the temperature sensor placed in the floor, the thermostat will control the heating: it will turn off the heating when the desired temperature is reached and turn it off when it drops by 2 °C.

‍To turn on the thermostat, turn the toggle switch to the "I" position. The indicator will start to light up green.

Temperature selection

‍When you first turn on the heating, set the thermostat setpoint temperature to the maximum by turning the control knob clockwise to the end. The thermostat will turn on the heating by indicating this with a red indicator light.

‍Wait until the room temperature is comfortable for you (it may take up to 3 days for the room to warm up). As soon as the room temperature is comfortable for you, turn the knob counter clockwise until the indicator changes to green. This position of the knob will fix the temperature that the thermostat will maintain in the room.

‍To turn off the heating, lower the switch to the "0" position.

Temperature selection

‍To turn off the heating, lower the switch to the "0" position.

Possible issues and solutions

Possible issues
and solutions

Additional information

Safety instructions

Warranty terms

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Version of instruction 2408

Installation and operation manual. Print version

Content

Content

Purpose

Purpose

Technical data

Technical data

Electrical connection diagram

Electrical connection diagram

Exploitation

Exploitation

Temperature selection

Temperature selection

Possible issues and solutions

Possible issues and solutions

Additional information

Additional information

Any questions? We are happy to answer

+38 091 481-91-81

Installation
and operation 
manual. Print version

Possible issues
and solutions