Technical Instructions
RDF20U Room Temperature Controller with LCD
Document Number 155-334
for Two-Pipe Fan Coil Units with Electric Heat
September 27, 2007
Page 10
Siemens Industry, Inc.
Mounting,
Installation and
Commissioning
Notes, Continued
▪
Installation Instructions are included with the controller.
WARNING:
•
Sensor inputs 7, 8, and 9
carry live voltage potential. If the sensor’s
cables must be extended, the cables used must be suited for live
voltage.
•
The cables used must meet the insulation requirements for live
voltage.
Calibrating the Sensor
If the room temperature displayed by the controller is inconsistent with the room
temperature being measured, the temperature sensor of the RDF20U can be
recalibrated. To recalibrate, change Parameter P09.
Specifications
Power Supply
Operating voltage
24 Vac, +20/-25%
Frequency
50/60 Hz
Power consumption
6 VA maximum
Fan control outputs 12, 11, 10-N
24 Vac
Rating
5 (3) A maximum
Valve control output 4-2 (NO)
24 Vac
Rating
5 (3) A maximum
Valve control output 5-2 (NC
24 Vac
Rating
5 (3) A maximum
Electric heat control output 6-2 (NO)
24 Vac
Rating
5 (3) A maximum
Return air temperature sensor
QAH11.1 safety class II
status input 9-8
NTC resistor 3K
at 77°F (25°C)
Changeover
—status input 7-8
QAH11.1, safety class II
NTC resistor 3K
at 77°F (25°C)
Status input D1 and GND
Contact sensing
SELV 6 to 15 Vdc/ 3 to 6 mA
Insulation against live voltage
4 kV, reinforced insulation
Operating action
Selectable (NO/NC)
Permissible cable length with copper
262 ft (80 m)
cable 14 AWG for connection to terminals
7, 8, and 9 and D1, GND.
Operational Data
Setpoint setting range
41°F to 95°F (5°C to 35°C)
Control deviation at 77°F (25°C)
+ 1°F (0.5K) maximum
Switching differential in Heating mode,
2 K (3.6°F)
adjustable
Switching differential in Cooling mode,
1 K (1.8°F)
adjustable
Dead zone X
dz
in Normal operation,
2 K (3.6°F)
adjustable
Setpoint differential W
D
, adjustable
2 K (3.6°F)
Setpoint, Economy mode , heating,
61°F (16°C)
adjustable
Setpoint, Economy mode , cooling,
82°F (28°C)
adjustable
Setpoint, Standby
, heating, adjustable
46°F (8°C)
Setpoint, Standby
, cooling, adjustable
OFF
