Pipe Fan Coil Unit With Radiator Or Floor Heating - Siemens RDG100 Documentation

Heating or cooling with

radiator or floor heating

Radiator, active in

cooling mode

Radiator in heating mode

Floor heating

ON/OFF control

Siemens

Building Technologies

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4.7.5

On 2-pipe applications with radiator, the thermostat controls a valve in heating /

cooling mode with changeover, heating only, or cooling only plus a radiator valve.

Cooling only is factory-set (P01=1).

In cooling mode, the valve receives an OPEN command if the acquired tempera-

ture is above the setpoint.

The radiator receives an ON command if the acquired room temperature drops

below "setpoint" minus "dead zone" (= "setpoint for radiator").

In heating mode, the radiator receives an OPEN command if the acquired tempera-

ture is below the setpoint. The fan coil unit is used as an additional heat source

when the heat energy controlled by the radiator is insufficient.

The fan coil unit receives an ON command if the temperature is below "setpoint"

minus "setpoint differential" (= setpoint for fan coil unit).

The radiator sequence can also be used for floor heating.

The "Floor heating limitation function" is described on page 17.

The diagram below shows the control sequence for 2-position control.

Heating mode

(automatic changeover = heating or heating only)

Y

Y1

YR

w

D

1

0

½ SDH

½ SDH

½ SDH

T[°C] Room temperature

W

Room temperature setpoint

Y1

Control command "Valve" or "Compressor"

YR

Control command "Radiator"

RDG100, RDG100T, RDG110, RDG140, RDG160 Basic Documentation

Functions

www.heronhill.co.uk

Cooling mode

(man. /auto. changeover = cooling or cooling only)

Y

1

w

T[°C]

0

½ SDH

½ SDH

SDH Switching differential "Heating" (P30)

SDC Switching differential "Cooling" (P31)

X

Dead zone (P33)

dz

w

Setpoint differential (P34)

D

YR

Y1

x

dz

w

T[°C]

½ SDC

½ SDC

½ SDH

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CE1P3181en

28 May 2009

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