
PI Thermostat TEF
TEF
PI Controller and Thermostat
Features
• Controller: Floating point temperature controller and positioner
• On/Off thermostat for 4-pipe or 2-pipe systems with fan function.
• Temperature control depending on room or return air temperature
• Integrated room temperature sensor
• Programmable user and control parameters
• Minimum, maximum set point limitation
• Enable/Disable change of set points and heating/cooling changeover
• Temperature display in Celsius or Fahrenheit
• Selectable Frost protection
• Operating Voltage 24V
Applications
• Individual PI-control of the temperature in rooms that are heated or cooled with 2-pipe systems or 4pipe systems using spring return fan coil valves.
• Cost efficient control of pressure dependent VAV units.
• Positioning of an on/off actuator by using the running time of the actuator
• Controlling the temperature output of a simple air-handling unit with one heating or cooling coil.
• Radiator or floor heating, cooling ceiling.
General Description
The TEF is a stand-alone electronic temperature controller with one PI control loop. It features 1 PI sequence
and 2 binary sequences. The TEF features 1 NTC temperature sensor input. One additional function is the
manual positioning of a floating actuator.
The TEF features 2 binary outputs (Relays). A detailed parameterization is possible with the use of a simple
configuration routine. The TEF can be configured using the standard operation terminal. No special tools or
software is required.
Ordering
Item Name Description/Option
TEF Compact PI controller 1 TI internal & external, 2 DO (Relays)
TEM Compact PI controller 1AI, 1 TI int & ext, 1 AO
Selection of actuators and sensors
Temperature Sensors: Use only our approved NTC sensors to achieve maximum accuracy. Recommended is
SDA-Tn10-20 as Duct sensor, SRA-Tn10 as Room sensor and SPA-Tn10-10 as immersion sensor.
Floating Actuators: Any actuators with less than 250 VAC, 100W are acceptable. Actuators with constant
running time are preferred for optimum functionality.
Binary auxiliary devices: E.g. pumps, fans, on/off valves, humidifiers, etc. Do not directly connect devices that
exceed 250 VAC, 100W.
V1.3a, 20100504 © Vector Controls GmbH, Switzerland Page 1/8
Subject to alteration

PI Thermostat TEF
Technical Specification
Power Power Supply 21.5 - 26.5 V AC 50/60 Hz
Power Consumption Max 2 VA
Electrical Connection Terminal Connectors
Output Signal
Temperature Sensor NTC resistor 10kΩ at 25 °C
Maximum allowed cable length with
Operation Control Temperature Range
Display precision 0.5 °K
Environment Operation
Transport & Storage
Ambient Humidity 0 to 95% rH No n Condensing
Standards conform according to
Product standards
Pollution Class Normal
Degree of Protection IP30 to EN 60 529
Safety Class III to EN 60 730
General Housing ABS plastic
Servicing Maintenance Free
Dimensions 105 x 90 x 37 mm (H x W x D)
Dimensions of package 160 x 100 x 40 mm (H x W x D)
Weight (including package) 215 g
Switching medium
Maximum Load
2
copper cable 1.5 mm
connections
Measured Temperature Range
Climatic Conditions
Temperature
Humidity
Climatic Conditions
Temperature
Humidity
Mechanical Conditions
EMC Standard 89/336/EEC
EMEI Standard 73/23/EEC
Automatic electrical controls for
household and similar use
Special requirement on
temperature dependent controls
for external
Dimensions
2
2 digital outputs,
Relays contacts
1A, 24V DC
80 m
10 to 35 °C (50…95 °F)
10 to 35 °C (50…94 °F)
To IEC 721-3-3
class 3 K5
0…50°C
<95% r.h.
To IEC 721-3-2 and IEC 721-3-1
class 3 K3 and class 1 K3
-25…70°C
<95% r.h.
class 2M2
EN 61 000-6-1/ EN 61 000-6-3
EN 60 730 –1
EN60 730 – 2 – 9
28
28
36
28 28
18
105
18
40
90
V1.3a, 20100504 © Vector Controls GmbH, Switzerland Page 2/8
Subject to alteration

PI Thermostat TEF
Display and Operation
Legend
1. Status LED for temperature control mode. Green = Cooling, Red = Heating,
Orange = setpoint or parameter menu active.
2. Status LED for analog control mode. Green = Input is equal to setpoint, Red = Input is not equal to
setpoint, Orange = setpoint or parameter menu active.
3. Buttons for operating the unit:
☼ POWER button, switches the controller on or off
UV UP and DOWN buttons, change setpoints and parameters.
T LEFT button, Activates analog control mode or
acts as ESC if in parameter menu.
RIGHT button, Activates temperature control mode, Heat / Cool change or
acts as ENTER if in parameter menu
4. Numerical LED display with 2 digits. Indication of current value or setpoint
Display
The TEF controller features a two digit number display and two dual colors status-LED.
Power Failure
All the parameters and set points are memorized and will not have to be reentered. The unit will return to the
operation mode it was in before the power failure. I required the unit would perform a reset cycle after
resuming of power supply. A reset is necessary if the unit was in operation during power failure. The actuator
position would then be lost and has to be regenerated. The controller assumes it is in the fully open position at
the return of power, completely close the actuator and then return to the mode of operation and setpoint it was
in before the power failure.
Frost Protection
The controller will activate if the temperature drops below 10°C (50°F). It will control the environmental
temperature up to 15° C (59° F) and then return to its previous mode. The LED will show FP and the status LED
blink alternating. Frost protection can be enabled/disabled using user parameter P7
Using an External Sensor
In order to utilize the external sensor, the internal sensor needs to be cut. The internal sensor is located in the
lower middle section of the PCB. It is marked with RT. It is recommended to cut one leg with a cutting tool and
bend the sensor to the side.
Calibrating the sensor
If the room temperature displayed does not agree with the room temperature effectively measured, the
temperature sensor can be recalibrated by adjusting user parameter P8. There is as well a potentiometer
located in the lower middle section on the PCB. Adjusting this will alter the temperature as well.
V1.3a, 20100504 © Vector Controls GmbH, Switzerland Page 3/8
Subject to alteration