Danfoss RET-B User manual

Data sheet RET-B
Battery Powered Room Thermostat
VDRKA122 © Danfoss 05/09 1
The RET B is a battery powered room thermostat
that combines the benefits of a conventional
analogue setting knob and an LCD display to
show temperature and thermostat status.
Styled on the RMT and RET thermostat
range, the RET B provides accurate electronic
temperature control without the need for an
external power supply. This makes it an ideal
solution for system upgrades when replacing
conventional electro-mechanical two-wire
thermostats.
The RET B utilizes a micro-processor which, in
addition to providing accurate temperature
control, also drives a small LCD display. During
normal operation, this LCD displays actual room
temperature and changes momentarily to show
set temperature whenever the setting dial is
moved. The LCD is also used to display output
relay state and to indicate when the batteries
require changing.
The micro-processor also provides other
added features not normally found in such
thermostats. These features include:
Selection of either on/off or chrono-•
proportional control
Cycle rate adjustment if chrono-•
proportional control is selected
Selection of heating or cooling control•
Selection of compressor delay timer if•
cooling operation is selected
Selection of Fahrenheit or Centigrade•
scaling
Common Features
Battery powered for ease of installation•
Ideal replacement for conventional 2-wire•
thermostat
Dry contacts, can switch 24V and low•
voltage control circuits
Micro-processor control provides added•
functionality
Analogue setting for ease of use•
LCD display shows temperature and•
thermostat status
Suitable for heating or cooling systems•
The range comprises of three models:
RET B
Basic thermostat with analogue setting and LCD
display.
RET B-LS
Thermostat with analogue setting and LCD
display, plus a manual Auto-Off switch to turn
the thermostat output off during periods when
it’s operation is not required. When set to Off
the LCD clearly shows that the thermostat has
been turned off.
RET B-NSB
Thermostat with analogue setting and LCD
display, plus a manual Day/Night switch
which, when set to Day position, controls
at the temperature set on the dial. When
Night is selected, the thermostat controls
at a temperature 7°F lower than the set
temperature.
Features:

Data sheet
VDRKA122 © Danfoss 05/09
RET-B
Battery Powered Room Thermostat
2
Thermostat configured for heating operation
Sw No. Setting Function
1 Heat
2 On/Off
3 Not active
4 °C (change for °F)
Or
1 Heat
2 Chrono
3 3 cycles per hour
4 °C (change for °F)
Or
1 Heat
2 Chrono
3 6 cycles per hour
4 °C (change for °F)
Thermostat configured for cooling operation
Sw No. Setting Function
1 Cool
2 No compressor delay
3 Not active
4 °C (change for °F)
Or
1Cool
2 Compressor delay active
3 2 min compressor delay
4 °C (change for °F)
Or
1 Cool
2 Compressor delay active
3 4 min compressor delay
4 °C (change for °F)
DIP Switch Settings:

Data sheet
VDRKA122 © Danfoss 05/09
RET-B
Battery Powered Room Thermostat
3
Features RET B RET B-LS RET B-NSB
Code number 087N7251 087N7255 087N7259
Temperature range 41 – 75 °F (5 – 30 °C)
Setting knob & LCD display
Auto / Off Selector switch
Day / Night selector switch
7°F (4°C) set-back
Low Battery indicator
Switched Voltage 10 - 24 Vac, 50 - 60 Hz
Switched Current 3 (1) A
Temperature Accuracy 1°C
Max. Ambient Temperature 103°F (45°C)
Power Supply 2 x AA/MN1500 alkaline batteries
Dimensions (mm) 3-5/16 wide x 3-5/16 high x 1-1/4 deep
Contact Type SPDT Type 1B
Specifications and
Ordering Information:
Wiring:
1 2 3
NC NO
OFF ON COM
1 2 3
NC NO
OFF ON COM
1 2 3
NC NO
OFF ON COM
ELECTRONICS
RET B
RET BNSB
RET BLS
ELECTRONICS
ELECTRONICS

Data sheet RET-B
Battery Powered Room Thermostat
4
Data sheet
Danfoss can accept no responsibility for possible errors in printed materials and reserves the right to alter its products without notice.
All trademarks in this material are property of the respective companies. Danfoss and Danfoss logotype are trademarks of Danfoss A/S. All rights reserved.
Danfoss Inc.
Baltimore, MD
Tel.: [phone], Fax: [phone]
www.na.heating.danfoss.com
Danfoss Inc.
Toronto, ON
Tel.: [phone], Fax: [phone]
www.na.heating.danfoss.com
VDRKA122 © Danfoss 05/09
RET-B
Battery Powered Room Thermostat