Danfoss RET B Data sheet

Datasheet

RET B Battery Powered Room Thermostat

Features

The RET B is a battery powered room thermostat that
combines the benets of a conventional analogue
setting knob and an LCD display to show temperature
and thermostat status. All models in the range are
available in hard-wired and wireless versions.

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 electro­mechanical two-wire thermostats.

The RET B utilises 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/o 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

• Voltage free outputs, can switch mains 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

• Available in hard-wired and RF versions

The range comprises 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/O switch to turn
the thermostat output o during periods when
it’s operation is not required. When set to O the
LCD clearly shows that the thermostat has been
turned o.
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 4°C lower
than the set temperature.

Installer Settings

Thermostat congured for heating operation Thermostat congured for cooling operation

Sw No Setting Function

1 Heat
2 On/O
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)

© Danfoss HS | 09/2015 | 532v07 VDRKF302

Sw No Setting Function

1 Cool
2 No compressor delay
3 Not active
4 °C (change for °F)

Or 1 Cool

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)

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Datasheet

TERMINAL 6

ErP

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RET B Battery Powered Room Thermostat

Specication and
Ordering Details

ErP Class

Features RET B (RF) RET B-LS (RF) RET B-NSB (RF)

Hard wired - Code number 087N725100 087N725500 087N725900

Wireless (RF) - Code number 087N727000 087N727200 087N727400

Temperature range 5 - 30°C

Setting knob & LCD display

Auto / O selector switch

Day / Night selector switch (4°C set-back)

Low battery indicator

Contact rating (hard-wired model) 10 - 230 Vac, 3 (1) A

Contact type (hard-wired model) SPDT Type 1B

Transmitter frequency (RF model) 433.92 MHz

Transmitter range (RF model) 30m max

Switching dierential ±1°C

Power supply 2 x AA/MN1500 alkaline batteries

Dimensions (mm) 85 wide x 86 high x 42 deep

Receiver (RF models) Features RX1 RX2 RX3

Order codes 087N747600 087N747700 087N747800

Single zone receiver

Two zone receiver

Three zone receiver

Power supply 230 ± 15% Vac, fused at 3A

Contact details 1-SPDT 1-SPDT, 1-SPST 1-SPDT, 2-SPST

Contact rating 24-230 Vac, 3 (1) A

Dimensions (mm) 138 wide x 88 high x 32 deep

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ERP Class

The products represented within this document are classied according to, and allow completion of, the Energy
Related Product (ErP) Directive System Package che and the ErP system data label. ErP Labelling obligation is
applicable from 26th September 2015.

ErP Class Product Function and ErP Description

TPI Room Thermostat, for use with on/off output heaters

An electronic room thermostat that controls both thermostat
cycle rate and in-cycle on/o ratio of the heater proportional

IV

to room temperature. TPI control strategy reduces mean water
temperature, improves room temperature control accuracy and
enhances system eciency.

Product

Class

Additional eciency

gain

2%

Wiring

RET B, RET B-LS, RET B-NSB

ELECTRONICS

NC

NO

1 2

OFF

3

COM

ON

ELECTRONICS

N L

RX1

1 2

COM

3

ZONE

1 ON

4

ZONE
1 OFF

ELECTRONICS

A

B

N

C 1

L

RX2 & RX3

3 4 5

2

COM

ZONE

1 ON

ZONE
1 OFF

ZONE

2 ON

6

ZONE

3 ON

RX3 ONLY

Danfoss Ltd.

Ampthill Road
Bedford MK42 9ER
Tel: [phone]
Fax: [phone]
Email: [e-mail]
Website: www.heating.danfoss.co.uk

Danfoss can accept no responsibility for possible errors in catalogues, brochures, and other printed material. Danfoss reserves the right to alter its products without notice. This also applies to products already
on order provided that such alterations can be made without subsequential changes being necessary in specifications already agreed.
All trademarks in this material are property of the respective companies. Danfoss and the Danfoss logotype are trademarks of Danfoss A/S. All rights reserved.

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© Danfoss HS | 09/2015 | 532v07 VDRKF302