Flush-mount room thermostat for round conduit box for 2-/4-pipe fan coils or DX type equipment, backlit LCD

Stock no. S55770-T291

Stock no. S55770-T291

Flush-mount room thermostat for round conduit box with LCD for fan coil units and compressors in DX-type equipment

  • Output for 1-speed or 3-speed fan

  • 2 or 3-position control outputs

  • Two multifunctional inputs for keycard contact, external room / return air temperature (QAH11.1, QAA32), heat / cool changeover, operation mode changeover, window contact on/off, dewpoint monitor, electrical heater enabled, fault contact

  • Operating modes: Comfort, Energy Saving and Protection

  • Automatic or manual heating/cooling changeover

  • Adjustable commissioning and control parameters

  • Minimum and maximum setpoint limitation

  • Color of housing: signal white (RAL 9003)

  • Backlit display

Application selectable:

  • 2-pipe system

  • 2-pipe system with electrical heater

  • 4-pipe system



Operating voltage

AC 230 V


50/60 Hz

Power consumption

2 VA

Positioning signal

2-position, 3-position

Control algorithm

2-point / PI

Ambient temperature, operation

0...50 °C

Setpoint setting range

5...40 °C

Measuring range, temperature

0…49 °C

Switching differential

0.5…6 K

Analog inputs

External room / return air temperature, Heat / Cool changeover, Operation mode changeover, Window contact on/off, Dewpoint monitor, Electrical heater enabled

Analog inputs, number


Analog input, signal

NTC 3k , Switch

Relay outputs

Fan: N.O. contacts, non-floating, Valve: N.O. contacts, non-floating

Relay outputs, number


Relay output, switching voltage

AC 230 V

Relay output, switching current

5 (2) A


Flush-mounting with recessed round conduit box, diameter min. 60 mm

Type of fixing

Recessed round conduit box diameter min. 60 mm

Degree of protection


Dimensions (W x H x D)

86 x 86 x 46 mm