2-Pipe Fan Coil Unit With Electric Heater - Siemens RDF800KN Series Manual

Heating or cooling with
auxiliary heater
Electric heating, active in
cooling mode
Note:
Electric heating in
heating mode
Electric heating and
manual changeover
Digital input "Enable
electric heater"
Enable electric heater
Note:
Caution
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3.6.4 2-pipe fan coil unit with electric heater (RDF800KN..,
RDF800KN/VB only)
On 2-pipe applications with electric heater, the thermostat controls a valve in
heating/cooling mode with changeover, heating only, or cooling only plus an
auxiliary electric heater.
Cooling only is factory-set (P01 = 1) with electric heater enabled (P13).
In cooling mode, the valve receives an OPEN command if the acquired room
temperature is above the setpoint. The electric heater receives an ON command if
the acquired room temperature drops below "setpoint" minus "dead zone" (=
setpoint for electric heater) while the electric heater is enabled (P13 = ON).
"Setpoint for electric heater" is limited by parameter "Comfort setpoint maximum"
(P10).
In heating mode, the valve receives an OPEN command if the acquired tempera-
ture is below the setpoint. The electric heater is used as an additional heat source
when the heating energy controlled by the valve is insufficient.
The electric heater receives an ON command, if the room temperature is below
"setpoint" minus "setpoint differential" (= setpoint for electric heater).
The electric heater is active in heating mode only and the control output for the
valve is permanently disabled when manual changeover is selected (P01 = 2).
Remote enabling/disabling of the electric heater is possible using input X1 or X2 for
tariff regulations, energy savings and so on.
Input X1 or X2 must be configured accordingly (P38/P40). See section 3.9.
The electric heater can also be enabled/disabled using the bus.
If "Enable electric heater" input uses the bus, the function must not be assigned to
a local input X1 or X2.
An electric heater must always be protected by a safety limit thermostat!
RDF800KN.., RDF800KN/VB, RDD810KN/NF Basic documentation
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CE1P3174en
2020-02-21