Siemens RDF302 Operating Instructions Manual

CE1B3079en / June 14, 2011 Subject to change Siemens Building Technologies

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Operating Instructions

RDF302

RDF302 – the room thermostat with RS 485 communications, using Modbus protocol, allows you to set the ideal room
temperature you want.
The thermostat provides Comfort, Energy Saving, and Protection mode.
The fan operates either in Auto mode or at a speed selected in Manual mode.
You can either take advantage of the thermostat's factory settings or adjust it as needed.

Display

Protection mode
Comfort mode
Energy Saving mode

Measured room temperature,
setpoints and parameters

Current time of day or
additional user information

Actual room temperature

Outdoor temperature

Fault indicator *

Condensation in the room *

Cooling demand/mode
Heating demand/mode
Electrical heater active

Automatic fan

Low fan speed

Medium fan speed

High fan speed

Buttons are locked

Operation and settings

Operating mode button

- Protection

- Comfort

- Economy

**

or in a system with manual

changeover

:

- Protection

- Comfort heating

- Comfort cooling

Colder / Warmer

Fan mode button

– Automatic fan (

)

– Manual fan (

)

* Needs to be configured by your HVAC installer
** Needs to be enabled via parameter P02

Change room temperature

+/–

Press + or – to increase or decrease the current room temperature setpoint for
Comfort mode. The thermostat changes to Comfort

.

The setting range is 5...40 °C, unless limited by parameters P09 and P10.

Adjust fan speed/fan mode

Press the button until you reach the desired fan mode.

In Auto mode, the thermostat automatically selects the fan speed based on
setpoint and actual room temperature. The fan continues to run at low speed
(factory setting) after the room temperature reaches the setpoint.

In manual mode, the fan always runs at the speed that you select:
Low fan speed
Medium fan speed
High fan speed
For a single-speed fan, you can change the mode between

and .

Change thermostat operating

Press operating mode button

to change the operating mode display.

In protection mode, the plant stops operating. However, if the room temperature
drops below 8 °C, heating is switched on to protect the room against frost.
Your HVAC installer can change the frost protection limit and set a heat
protection limit as needed:

Changes made by installer:  Frost protection: ........... ˚C

Heat protection: ........... ˚C

In Comfort mode, the thermostat maintains the room temperature on the
setpoint which can be readjusted using the + and – buttons.

In Energy Saving mode, the room temperature is maintained at a lower or higher
setpoint, thus saving energy and money. Adjust parameters P11 and P12 to
change the preselected setpoints.
The thermostat can be set to Energy Saving mode either by pressing the
operating mode button if enabled (P02 = 2), or via an external signal (switch or
Modbus command) such as window contact, keycard or presence detector.

Change from heating to cooling mode

/

Changeover between cooling and heating is either automatic using a
heating/cooling changeover sensor or a remote changeover switch or via
instruction from the central management station via Modbus, or manual by
pressing operating mode button

. No changeover is possible if the thermostat

is configured for cooling only or heating only (see parameter P01).

Display for automatic changeover or heating only/cooling only:

Heating valve is open
Cooling valve is open

Display for manual changeover:

Thermostat is in heating mode
Thermostat is in cooling mode

CE1B3079en / June 14, 2011 Subject to change Siemens Building Technologies

Button lock

Press operating mode button

for 5 seconds to lock or unlock the buttons if
manual button lock is configured (parameter P14 = 2).
The thermostat automatically locks the buttons 10 seconds after the last
adjustment if "Auto lock" is configured (P14 = 1).

The key symbol

indicates locked buttons.
Notes: The button lock cannot be released (unlocked) once the buttons were
locked by the master through the Modbus command.

Reminder to clean filters and for external faults

FIL *

AL1 *
AL2 *

This message reminds you to clean your HVAC equipment filters.
It is displayed after ………… “fan operating hours” and disappears when the
thermostat is set to Protection (

).

These messages inform you on external faults *:

AL1 : ...………………………………….
AL2 : ...………………………………….

Recalibrating the sensor

If the room temperature displayed by the thermostat does not agree with the
temperature effectively measured (after min 1 hour of operation), the
temperature sensor can be recalibrated through p arameter P05.

Note: energy saving mode

The energy saving setpoints are factory-set to 15 °C for heating and 30 °C for
cooling. Use parameters P11 and P12 to adjust the values.

Important: You can set these setpoints to OFF; the thermostat then is
inactive, i.e. no protective heating or cooling function.

Risk of frost!

Commissioning

You can adjust a number of different control parameters to adapt the thermostat to your
system and optimize control performance. You can do this during operation either via the
buttons on the thermostat or using a commissioning tool via Modbus.

Baud rate and parity

The Baud rate can be adjusted to 4800 bps, 9600 bps, 19200 bps (factory
setting) or 38400 bps. The Parity can be s et to none, odd or even (factory
setting). Your HVAC installer can set them through the additional
parameters.

Important: Once you made any changes on the baud rate or parity, you must
reset the power before the changes become effective.

* Needs to be configured by your HVAC installer

Control parameters

Proceed as follows to change the most important control parameters (your HVAC installer can set additional parameters):

+/–

1. Press the – and + buttons simultaneously at least 3 seconds.
Release, and within 2 seconds, press + again for 3 seconds. "P01" is displayed.

2. Repeatedly press the + or – button to select the required parameter.

-

--

-

-

-

3. Press + and – simultaneously. The current value of the selected parameter begins to flash, allowing you to
change the value by repeatedly pressing + or –.

4. The next parameter is displayed when you press + and – again simultaneously.

5. Repeat steps 2 to 4 to display and change additional parameters.

6. Press + or – until “End” is displayed, and then press + and – simultaneously to save the change and exit
parameter entry mode.

Parameter Description

Factory setting Setting range Adjustment 

P01 Control sequence

2-pipe: [0…3]
1 (Cooling only)

4-pipe: [2…4]
4 (Heating & Cooling)

0 = Heating only
1 = Cooling only
2 = Manual Heating or Cooling
3 = Auto Changeover
4 = Heating & cooling

P02 Mode selection by user via operating mode button 1 (Comfort, Protection)

1 = Comfort, Protection
2 = Comfort, Energy Saving,

Protection

P04 Selection of °C or °F °C

0 = °C
1 = °F

P05 Sensor calibration 0.0 °C

-3...3 °C

P06 Standard temperature display 0 (Room temperature)

0 = Room temperature
1 = Setpoint

P07 Additional user infor mation 0 (no display)

0 = No display
1 = Temperature in °C/°F
2 = Outside temperature

(via bus)
3 = Time of day (12 h, via bus)
4 = Time of day (24 h, via bus)

P08 Comfort basic setpoint 21 °C 5...40 °C

P09 Minimum setpoint limitation in Comfort (WminComf) 5 °C 5...40 °C

P10 Maximum setpoint limitation in Comfort (WmaxComf) 35 °C 5...40 °C

P11 Setpoint of heating in Energy Saving (WheatEco) 15 °C OFF, 5 °C…WcoolEco

P12 Setpoint of cooling in Energy Saving (WcoolEco) 30 °C OFF, WheatEco…40 °C

P13 *** Electrical heater in coo ling mode ON

OFF = disabled
ON = enabled

P14

Button lock
(Press operating mode button

for 5 seconds to lock

or unlock the buttons)

0 (Disabled)

0 = Disabled
1 = Auto lock
2 = Manual lock

*** Parameter P13 is only displayed for application "2-pipe with electric heater".

All temperature settings are in increments of 0.5 °C.

 Please record all changes you make!