Danfoss RA 2000 User manual

DKCD VD.51.Q1.12 © Danfoss 10/2003 1
EN 215-1
HD 1215-2
Data sheet Radiator Thermostats type RA 2000
Valve bodies type RA-FN and RA-G
Application
Robustly built and designed to meet the rigours of
the commercial and industrial sectors, a
comprehensive range of RA2000 radiator
thermostats is available for practically all systems
and installation conditions. Sensors and valve
bodies are packed separately so that they can be
mixed and matched for any duty.
Valve bodies are of nickel-plated brass. The
different types are shown below:
RA-FN For steel pipe. Straight, Vertical angled
from 3/8” to 1” BSP and horizontal angled from 3/8”
to ¾” BSP.
RA-G Straight and Vertical Angled for one-pipe
pumped or gravity systems, ½”, ¾” and 1” BSP.
RA-N Valves with integral presetting facility. See
separate Data Sheet.
In all valves, the pressure pin of the gland seal is
made of chromium steel and this works in a
lifetime-lubricated O Ring seal. The complete gland
assembly can be replaced without draining down
the system.
The protective cap supplied with each new valve
may be used for manual control during installation
only. It should not be used as isolation device. A
manual shut off device is available as a spare part.
Sensors are available as both standard and
tamperproof, built-in and remote sensing models, as
well as remote adjusting. All have range limiting and
locking. They are for use with Danfoss valve bodies
types RA-FN and RA-G.
RA 2000 sensors are not suitable for use with
RA-FR valves.
RA2000 Features
´ Robust Construction
´ Accurate Temperature Control
´ Full Range
´ Range Limiting and Locking
´ Tamper Resistant Models
´ Remote Sensors
´ Remote Wall Adjuster
´ Low Temperature Models
´ Presetting Valves
System
RA-FN straight valve body RA-FN vertical angle valve body RA-FN horizontal angle valve body
All Danfoss RA2000 radiator thermostats are
manufactured to highest standards, and are
Approved to EN 215 approved to the European standard EN 215 and di-
mension standard HD 1215-2, which supersedes BS
6284.
RA 2910 built-in sensor RA 2920 tamperproof RA 5062 remote
sensor temperature adjuster
RA-G straight valve body RA-G vertical angle valve body

Data Sheet Radiator thermostats for one-pipe and two-pipe systems
2 VD.51.Q1.12 © Danfoss 10/2003 DKCD
Valve bodies for two-pipe systems type RA-FN
1) Remote sensors are recommended
2) Kvs-maximum indicates the water flow (Q) with valve fully open
Selection and specification
Should water treatment be
used it is essential that dosing
instructions of the manufacturer
are strictly observed. It is
recommended that formulations
containing mineral oil are
avoided.
RA 2910 013G2910 Built-in 5 - 26 °C (1)
RA 2920 013G2920 Built-in, tamper proof 5 - 26 °C (1)
RA 2914 013G2914 Built-in, low temperature range model 5 - 22 °C (1)
RA 2912 013G2912 Remote sensor, 0 - 2 m capillary tube (2) 5 - 26 °C
RA 2922 013G2922 Remote sensor, 0 - 2 m capillary tube, tamper proof (2) 5 - 26 °C
RA 2916 013G2916 Remote sensor, 0 - 2 m capillary tube (2) 5 - 22 °C
RA 5062 013G5062 Remote temperature adjuster, 0 - 2 m capillary tube (3) 8 - 28 °C
RA 5065 013G5065 Remote temperature adjuster, 0 - 5 m capillary tube (3) 8 - 28 °C
RA 5068 013G5068 Remote temperature adjuster, 0 - 8 m capillary tube (3) 8 - 28 °C
Type Code no. Sensor (Max. sensor temperature 60°C) Temp. range
Xp = 2K
RA2000 thermostatic sensors (4) supplied in separate boxes
(1) Temperatures shown are for units with built-in
sensors which are subject to influence from
radiation and flow temperature. Without these
influences, max. temperature is 2 °C higher at de-
sign load condition.
(2) Remote sensors are supplied with all the
capillary tube coiled within the sensor. When
installing the sensor, only the length required
should be uncoiled.
(3) Remote temperature adjusters are supplied with
adapters for RA-valves. Adaptors for older valves
can be ordered separately:
RAVL-adaptor, code no. 013G5192
RAV-adaptor, code no. 013G5193
(4) Important note: Do not use any RA2000
sensors with RA-FR bi-directional valve bodies.
(1) These valve bodies are supplied with compression
fittings for copper tube to BS 864. When these
connections are removed, a standard BSP screwed
inlet BS 21 remains.
(2) Kvs-maximum indicates the water flow (Q) with valve
fully open.
(3) Remote sensors are recommended.
Working pressure = static + differential pressures. The
maximum differential pressure specified is the maximum
pressure at which the valves give satisfactory control. As with
any device which imposes a pressure drop in the system,
noise may occur under certain flow/pressure conditions. To
ensure quiet operation, maximum pressure drop should not
exceed 40 to 45 kPa. The differential pressure can be
reduced by the use of Danfoss differential pressure controls.
When using RA2000 remote temperature adjusters the kv-values stated in the table above must
be reduced by approximately 40% to take into account the different characteristics of these
sensors.
Valve bodies for one-pipe pumped or gravity systems, type RA-G
kv-value
(m3/h at 1 bar pressure drop)
P-band = K
013G3384
013G3386
013G3388

DKCD VD.51.Q1.12 © Danfoss 10/2003 3
7 9,5 14 17 20 °C
l¬123•
5 7,5 12 15 18 °C
7 9,5 14 17 20 23 26 28°C
l¬12••3••4 5l
5 7,5 13 15 18 21 24 26°C
10 14 18 22 26 30°C
¬1 2•••3•••4 5
8 12 16 20 24 28°C
¬= Frost protection setting
RA 5062, RA 5065, RA 5068
RA 2914 RA 2916
RA 2920, RA 2922
RA 2910, RA 2912
To support the range of RA2000 radiator
thermostats, a wide selection of spare parts and
accessories for both sensors and valve bodies is
available. The table above lists the more popular
parts including fittings.
Replacement Gland Seals
All Danfoss radiator thermostats manufactured
since the early 1960’s have gland seals which are
replaceable without the need to drain down the
system.
Replacement Sensors for earlier Danfoss
Thermostats
In order to provide a service and upgrade option for
earlier RAV and RAVL valve bodies, a range of
service sensors is available.
Please request details.
The required room temperature is set by rotating
the sensor handle to match the scale number with
the setting register. The correlation between scale
Setting the temperature numbers and room temperatures (at Xp=2K) is
shown on the right.
The values shown are for guidance only.
Accessories
Data Sheet Radiator thermostats for one-pipe and two-pipe systems
Accessories for RA 2000 sensors Code no.
Anti.theft plugs for sensors (50 pcs) 013G1232
Threaded range limiting pins (30 pcs) 013G1237
RA 2020/2022 scale cover (20 pcs) 013G1233
Toolkit, comprising allen key & locking pin tool 013G1236
Accessories for RA-FN and RA-G valves Code no.
Gland seal for RA-FN and RA-G valves (Can be replaced without draining down) 013G0290
Manual positive shut-off knob 013G5002
Spare protective green cap 013G0275
Compression fittings for RA-FN valves Code no.
3/8" x 10 mm for RA-FN 10 013G4100
3/8" x 12 mm for RA-FN 10 013G4102
½" x 10 mm for RA-FN 15 013G4110
½" x 12 mm for RA-FN 15 013G4112
½" x 15 mm for RA-FN 15 013G4115
¬= Frost protection setting
¬= Frost protection setting

Data Sheet Radiator thermostats for one-pipe and two-pipe systems
4 VD.51.Q1.12 © Danfoss 10/2003 DKCD
Radiator thermostats are sophisticated proportional
control.
1) The operating principles of thermostats
The function of the actuator unit is to sense the am-
bient temperature, compare it with the required tem-
perature, and correct the valve setting in accord-
ance with the difference, as illustrated in fig. 1.
European Standard EN215 requires that radiator
thermostats meet various operating criteria. Danfoss
radiator thermostats meet or exceed these require-
ments in every respect. A brief description of the key
considerations is given below.
2) Differential pressure dependence.
The closing characteristic of a radiator thermostat
depends on the pressure conditions in the valve. In
fig. 2, curve 1 applies to the actuator unit without
counterpressure from system differential pressure,
while curve 2 shows the offset when the
counterpressure increases proportionately to the
valve closure. The effect is a result of the elasticity
of the actuator unit which should, therefore, not be
too large.
3) Time constant
To give reasonably fast and stable control, a radia-
tor thermostat must not be too slow in its reaction to
temperature variations. The time constant (fig. 3)
depends on the specific heat and surface of the sen-
sor.
At a sudden change of the ambient temperature at
time 0, the thermostat will react as shown, relative
to time. The time constant is defined as the time
used by the spindle for 63% of its full movement.
4) Flow temperature dependence
Flow temperature dependence occurs largely in the
case of actuator units with built-in sensors since
heat transmission takes place from the valve body
to the sensor of the unit (Fig. 4), with the possible
effect, under full load conditions, of controlling the
room temperature at a lower temperature than re-
quired. Insulating plastic materials for thermostat
base, internal heat shields and good product design
in positioning the sensing element away from the
heat source, help reduce this dependence. Danfoss
recommend that radiator thermostat sensors are
mounted horizontally, away from the effects of heat
rising from hot valve and pipework.
5) Hysteresis
If the spindle movement of an actuator unit is
measured at, first, increasing and then decreasing
temperatures, there will be a difference between the
point where the valve just closes and the point
where it opens again – see fig. 5. This difference is
termed hysteresis and is caused by friction in the
actuator unit and valve body. It is desirable that
hysteresis should be as small as possible.
Setting the temperature
1
2
3
4
5

DKCD VD.51.Q1.12 © Danfoss 10/2003 5
Sensor operating principle The RA2000 thermostatic sensor consisting of a bel-
lows system and saturated vapour charge provides
proportional control, as opposed to On/Off. The sen-
sor is actuated by ambient temperature changes.
The calibrated pressure in the bellows corresponds
to the temperature of the charge. This pressure is
balanced by the force of a regulating spring.
On a rise in ambient temperature, the vapour pres-
sure increases in the bellows, moving the valve
cone towards the “closed” position, until equilibrium
exists between the bellows and spring. On a drop in
ambient temperature, the vapour pressure falls, al-
lowing the bellows to contract and the valve cone to
move towards the “open” position until a state of
equilibrium is re-established.
The vapour charge will always condense at the cold-
est part of the sensor, usually that furthest away
from the valve body. The radiator thermostat will
therefore always respond to changes in room tem-
perature and will not be affected by the water tem-
perature itself. However, when the air around the
sensor is heated by the hot valve body and
pipework, then the sensor can register a higher tem-
perature than that of the rest of the room. For this
reason, Danfoss recommend that the sensor is
mounted horizontally whenever possible.
To ensure that the valve capacity of a fully opened
valve is not significantly greater than that at 2
degrees C P-deviation, all RA-FN valves have a
modified valve characteristic. This improved valve
characteristic maintains hydraulic balance during
start-up.
Proportional band
Proportional temperature controls try to maintain
equilibrium between heat loss and heat input. They
react proportionately to any deviation from a set
temperature level, until heat input is either com-
pletely shut off or is at its maximum. The tempera-
ture levels at which this occurs are presettable, and
the band between the two levels, measured in K
(degrees C) is the proportional band.
Danfoss radiator thermostats can be sized to oper-
ate across a defined proportional band. A range of
0,5 – 2K is recommended. In providing proportional
control, they ensure smaller swings in room tem-
perature than, say, a conventional room thermostat
which gives on/off control and needs to cycle
throughout its switching differential each time it op-
erates.
1. Thermostatic element
2. Bellows
3. Setting dial
4. Setting spring
5. Limit pin
6. Pressure pin
7. O-ring seal
8. Valve cone
9. Valve body
10. Nozzle
Data Sheet Radiator thermostats for one-pipe and two-pipe systems
Hydraulic balance
Definitions kv-Coefficiant of flow
The kv-value of a valve shows the quantity of liquid,
in m3/h, that the valve will pass with a pressure
drop of 1 bar across the valve. This value is used in
the following formulae to calculate flow rates for
valve sizing purposes.

Data Sheet Radiator thermostats for one-pipe and two-pipe systems
6 VD.51.Q1.12 © Danfoss 10/2003 DKCD
The P-band value depends on the chosen valve i.e.
RA-FN 15 will work with a P-band of 2K.
RA-FN 20 will work with a P-band of about 1.4K.
The Kv-value can also be calculated on the basis of
the formula
Kv = Q Q(m3/h), ∆p (bar)
√ ∆p
0.044 = 0.044 x 3600 = 0.158 m3/h
1000
Kv = 0.158 = 0.71
√0.05 Note: 1m3/h = 0.278 l/s
Capacities
Use the following sizing charts
to select the correct valve for
the radiator in question.
Heat requirement: 2.05 kW
Temperature drop: 11°C
Differential pressure
across the radiator: 0.05 bar (5 kPa)
Solution:
Water flow through the radiator per hour:
Q = 2.05 = 0.044l/s
4.2 x11
Capacity with P-band between 0.5K and 2K with RA 2000 sensor
Note:
As with any device which
imposes a pressure drop
system, noise may occur under
certain flow/pressure conditions.
To ensure quiet operation,
maximum pressure drop should
not exceed 40 to 45kPa.
Example
RA-FN
for two-pipe systems
RA-G
for one-pipe systems

DKCD VD.51.Q1.12 © Danfoss 10/2003 7
Fitting Danfoss radiator
thermostats
Built-in sensors
are best fitted horizontally so that the ambient air can
pass freely over the sensor without being affected by
heat from valve and possibly surface pipes.
Remote sensors
should be used when:
- curtains cover the sensor
- or the sensor is affected by surface pipes.
- It is necessary to mount the sensor in the vertical
position because of adjacent obstructions and the
valve body is flow mounted.
The remote sensor must be mounted on the wall, away
from curtains, or on the skirting board beneath the
radiator if free of surface pipes. All remote sensors are
now supplied with ultra-thin capillary. Simply pull out
the length required (2m max.) and fix using clips
provided.
Remote temperature adjuster
isidealforusewhenthevalveispositionedinaccessible
to the user. The temperature adjuster should be
mounted 1.5m above the floor.
IMPORTANT
Do not use RA 2000 sensors with RA-FR reversible
valve bodies.
Changing the gland seal
Data Sheet Radiator thermostats for one-pipe and two-pipe systems
Should the valve body gland seal shows signs of
weeping, the gland seal can be renewed in a few
minutes with the system in operation.
Order gland seal 013U0070 for RAVL and RAV
valves. 013G0290 for RA-FN and RA-G. (Sold in
packs of 10 units, complete with instructions).

Data Sheet Radiator thermostats for one-pipe and two-pipe systems
8 VD.51.Q1.12 © Danfoss 10/2003 DKCD
Dimensions
*) Add 32mm to L7 to allow for sensor removal fitting
**) "UK" indicates horizontal angle type valve body
Built-in sensor
on RA-FN or RA-G body Built-in tamperproof sensor on RA-FN or RA-G body
Built-in sensor
on RA-FN body, horizontal angle (UK)
Remote sensor
on RA-FN or RA-G body Remote temperature adjuster
DN D d2
RA-FN 10 10 Rp3/8R3/860 85 27 52 22 47 96 22 27
RA-FN 10 UK** 10 Rp3/8R3/8103 26 51 22 22 27
RA-FN 15 15 Rp1/2R1/267 95 30 58 26 47 96 27 30
RA-FN 15 UK** 15 Rp1/2R1/2104 29 57 44 27 30
RA-FN 20 20 Rp3/4R3/474 106 34 66 29 47 96 32 37
RA-FN 20 UK** 20 Rp3/4R3/4105 34 66 30 32 37
RA-FN 25 25 Rp1/1R1/190 126 40 76 34 47 96 27 30
RA-G 15 15 Rp1/2R1/268 96 30 58 27 50 99 27 30
RA-G 20 20 Rp3/4R3/474 106 34 66 30 50 99 32 37
RA-G 25 25 Rp1/1R1/190 126 42 78 34 54 103 41 46
L1L2L3L4L5L6L7*L
8L9L10
Type
Arc.flats
S1S2
Connection (ISO 7-1)