
Datasheet
ORT-01 Electronic Room Thermostat
for use with OpenTherm boilers
Features
Dimensions
The ORT-01 is a sophisticated room thermostat
which provides modulating control of OpenTherm
equipped condensing gas boilers.
Unlike traditional thermostats, the ORT-01
exchanges data with the boiler it controls as
opposed to simple on/o commands. This type
of control, in addition to providing closer, more
accurate room temperature control, also ensures
that the ow temperature from the boiler is
modulated down to as low a level as prevailing
load permits, thus signicantly increasing the
proportion of the boiler operating time that is
spent in economic condensing mode.
The thermostat is fully compliant with the
OpenTherm communications protocol including
low load regulation and domestic hot water
keep hot feature now in common use in many
combination boilers.
3
78
86
The thermostat utilises a micro processor which
provides the accurate PI control algorithm and
manages the bi-directional data communication
with the boiler.
User interface is by means of an easy to
understand setting dial and a status LED indicator
that provides information on boiler output and a
common alarm indication which is lit whenever a
fault is encountered within the boiler.
• Provides full modulation to OpenTherm
equipped boilers
• Simple to install 2-wire non-polarised low
voltage communications
• Accurate PI room temperature regulation
• Signicantly improves boiler eciency
• Dial setting provides easy to understand
user interface
85
© Danfoss HS | 09/2015 | 126v04 VDRKJ302
8
42
1

Datasheet ORT-01Electronic Room Thermostat
Technical Performance
Laboratory tests comparing the performance of
the ORT-01 OpenTherm room thermostat with
that of a traditional electro-mechanical on/o
thermostat, clearly show that modulating control
gives the best level of comfort, the lowest level
of energy consumption and the lowest level of
harmful CO2 emissions.
The speed of response of the modulating
thermostat is also signicantly faster than it’s
on/o counterpart allowing even small changes
in room temperature to be communicated to the
boiler.
Results from tests made in a controlled laboratory
environment, show that savings in the order of
15% are achievable when comparing the control of
an OpenTherm boiler controlled by a modulating
room thermostat compared to the same boiler
being controlled by a traditional mechanical
on/o thermostat.
Mechanical On/O Thermostatic Control of OpenTherm boiler
Modulating Thermostatic Control of OpenTherm boiler
2
© Danfoss HS | 09/2015 | 126v04 VDRKJ302

Datasheet
ORT-01 Electronic Room Thermostat
Thermostat Specications
ErP Class
Features ORT-01
Code Number 087N774300
Temperature range 8-30°C
Maximum ambient temperature 45°C
Control type P + I
OpenTherm software version 2.3
Domestic hot water keep hot feature •
Holiday mode •
ID 14 low load control •
Thermostat output Data
Construction EN60730-2-9
IP rating IP20
Supply voltage 24V DC from boiler
Wiring, non-polarised 2 wire bus •
Control pollution situation Degree 2
Ball hardness test 75°C
Dimensions (mm) 86 high x 85 wide x 42 deep
ERP Class
The products represented within this document are classied 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
Modulating Room Thermostat, for use with modulating heaters
An electronic room thermostat that varies the ow temperature
V
of the water leaving the heater dependent upon measured room
temperature deviation from room thermostat set point. Control is
achieved by modulating the output of the heater.
Additional eciency
gain
3%
Wiring
Product
Class
OpenTherm
connections
B
A
O
Important - To avoid damage to Boiler and Thermostat, connect only to OpenTherm connections on boiler, do not connect to any other
power source.
O
in ORT- 01
Wires can be
crossed
OpenTherm
connections
in boiler
© Danfoss HS | 09/2015 | 126v04 VDRKJ302
3

Datasheet
ORT-01 Electronic Room Thermostat
Danfoss Randall Ltd.
Ampthill Road
Bedford MK42 9ER
Tel: 0845 1217 400
Fax: 0845 1217 515
Email: danfossrandall@danfoss.com
Website: www.danfoss-randall.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 subsequent 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.
4
© Danfoss HS | 09/2015 | 126v04 VDRKJ302