Technical data
Table Of Contents
- 1. About this document
- 2. Summary
- 3. Functions
- 3.1 Temperature control
- 3.2 Operating modes
- 3.3 Room temperature setpoints
- 3.4 Applications overview
- 3.5 Additional functions
- 3.6 Control sequences
- 3.7 Control outputs
- 3.8 Fan control
- 3.9 Multifunctional input, digital input
- 3.10 Handling faults
- 3.11 KNX communications
- 3.11.1 S-mode
- 3.11.2 LTE mode
- 3.11.3 Zone addressing in LTE mode (in conjunction with Synco)
- 3.11.4 Example of heating and cooling demand zone
- 3.11.5 Send heartbeat and receive timeout
- 3.11.6 Startup
- 3.11.7 Heating and cooling demand
- 3.11.8 Fault function on KNX
- 3.11.9 KNX switching groups (RDF301.50, RDF301.50H only)
- 3.12 Communication objects (S-mode)
- 3.13 Communication objects (LTE-mode)
- 3.14 Control parameters
- 4. Handling
- 5. Supported KNX tools
- 6. Connection
- 7. Mechanical design
- 8. Technical data
3.6.4 2-pipe fan coil unit with electric heater
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 enabled electric heater (P13).
In cooling mode, the valve receives an OPEN command if the acquired tempera-
ture 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 (parameter P13 = ON).
Note: "Setpoint for electric heater" is limited by parameter "Maximum setpoint for
Comfort mode" (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 heating
source when the heating energy controlled by the valve is insufficient.
The electric heater receives an ON command, if the 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 via input X1 or X2 for
tariff regulations, energy savings, etc.
Input X1 or X2 must be commissioned accordingly (parameters P38, P40). See
section 3.9 "Multifunctional input".
The electric heater can also be enabled / disabled via bus.
If "Enable electric heater" input is used via bus, then 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!
H
eating or cooling with
auxiliary heater
Electric heating, active in
cooling mode
Electric
heating in
heating mode
Electric
heating and
manual changeover
Digital input "Enable
electric heater"
KNX
R
Enable electric heater
Note:
Caution
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Siemens RDF301, RDF301.50..., RDF600KN Basic documentation CE1P3171en
Building Technologies Functions 2014-05-23