Danfoss QT Data sheet
Data sheet
Thermostatic actuator QT
- return temperature control with AB-QM valves
Description
Benefits
QT is a self-acting thermostatic actuator
designed to be used as return temperature
control thermostat in one-pipe heating systems.
QT is dedicated to be used with AB-QM
automatic balancing & control valve.
AB-QM together with QT is a complete
one-pipe solution: AB-QT.
Main data:
• Setting range: 35-50 °C, 45-60 °C, 65-85 °C
• Designed for AB-QM DN 10-32
• Easy-to-install external surface sensor
• Reduces actual riser flow to match heat
demand
• Improved room temperature control
• Reduced overheating of the building
• Reduced heating cost
Ordering
QT thermostatic actuator
Setting range
(°C)
45 … 60
35 … 50
65 … 85
fit to
AB-QM
DN 10 -20 003Z0382
DN 25-32 003Z0383
DN 10 -20 003Z0384
DN 25-32 003Z0385
DN 10 -20 003Z0386
DN 25-32 003Z0387
Code No.
Accessories
Typ e
Pocket for submersible sensor
Adapter kit QT (DN 10-20)
Adapter kit QT (DN 25-32)
Sensor pocket kit
QT flow set ting tag
Code No.
003Z0391
003Z0392
003Z0393
003Z0394
003Z0395
AB-QM valves
DN
10 LF 150
10 275 00 3Z1211 00 3Z1201
15 LF 275
15 450 003 Z1212 00 3Z1202
20 900 G 1 A 003Z 1213 G 1 A 003Z1203
25 1.700 G 1¼ A 0 03Z1214 G 1¼ A 00 3Z1204
32 3.200 G 1½ A 0 03Z1215 G 1½ A 003Z1205
Q
(l/h)
max.
Ext. thread
(ISO 228/1)
G ½ A
G ¾ A
Code No. AB-QM
00 3Z1261
003Z1262
Ext. thread
(ISO 228/1)
G ½ A
G ¾ A
Code No.
00 3Z1251
00 3Z1252
© Danfoss | 2018.07 VD.C6.U4.02 | 1
Data sheet Thermostatic actuator QT
Applications
Fig. 1 Fig. 2 Fig. 3
QT is designed to be used in combination with
AB-QM in one-pipe heating systems. AB-QM
together with QT converts one-pipe heating
system into energy efficient variable flow
system, where flow in the risers is dynamically
adjusted to match the load in the riser by control
of return water temperature.
In one-pipe systems flow in the riser is always
present. TRV on the radiator controls room
temperature by controlling flow through
radiator. However, by reducing flow through the
radiator, water flow is not reduced but diverted
to a by-pass and thus total water flow in the riser
remains permanent. Therefore at partial loads
water temperature in the pipe is increasing.
As a result the riser itself with the by-pass pipe
continues to heat the room. This can cause
overheating of the room.
After the building is renovated the heating
system becomes oversized since the heat losses
of the building decrease. As a result overheating
issue increases even more.
AB-QM mounted in the riser provides a robust
solution that offers reliable balance of one-pipe
heating system at all system conditions. As a
result, every riser gets design flow – and never
more than that. Each riser becomes independent
part of installation.
In addition, QT as a self-acting return
temperature thermostat installed on AB-QM
provides flow control through the temperature
of return water in the riser. By this water flow in
the riser is dynamically controlled to match the
actual load in the riser. This results in improved
room temperature control and greatly reduced
overheating of the building. Thus one-pipe
systems become energy efficient variable flow
systems, similar as Two-pipe systems are.
Typical applications are:
- one-pipe vertical riser based heating system
(Fig. 1)
- one-pipe horizontal loop based heating
system (Fig. 2)
- two-pipe vertical riser based heating system
without TRV’s, such as staircase or bathroom
risers (Fig. 3)
2 | VD.C6.U4.02 © Danfoss | 2018.07
Data sheet Thermostatic actuator QT
Technical data
General data
Setting range
Temperature tolerance ±3
1)
P-band
Max adm temperature at sensor 90
Capillary tube length m 0.6
Materials
Housing CuZn36Pb2As (CW 602N)
Cone and diaphragm support MPPE (Noryl)
Main spindle (CW 614N) Zn39Pb3
Sensor cap Polypropylene (Borealis HF 700-SA)
Temperature sensor Copper, mat. No. 2.0090
Adapter
Nut
1)
with AB- QM DN 10-20, at 50 % flow setting
2)
with AB-Q M DN 25-32, at 50 % flow setting
QT setti ng 0 (min) QT setti ng 6 (max)
AB-QM
50% setting
°C
DN 10 -20 CuZn39Pb3 (CW 614N), coated with Cu Zn8B
DN 25-32 CuZn39Pb3 (CW 614N)
DN 10 -20 CuZn39Pb3 (CW 614N), coated with Cu Zn8B
DN 25-32 CuZn39Pb3 (CW 614N)
35 … 50 45 … 60 65 … 85
2)
5 1)/8
QT setti ng 0 (min) QT setti ng 6 (max)
AB-QM
50% setting
Mounting
P band P band
P band P ba nd
Fig. 4 Functional graph for QT on AB-QM DN 10-20 Fig. 5 Functional graph for QT on AB- QM DN 25-32
When used in vertical based one-pipe heating
system (Fig.1) AB-QM is to be installed after the
last radiator in the riser.
In horizontal based heating system (Fig.2) AB-QM
can be mounted also elsewhere in the loop, as
long as the temperature sensor can be mounted
after the last radiator in that loop.
QT should be mounted on the AB-QM by hand.
Installation of the sensor
For proper heat transfer between a heating
water pipe and the thermostat sensor, it is very
important to apply thermo paste (included in the
box) on the surfaces in contact.
Sensor itself can be mounted in any direction.
For best performance of QT it is recommended
to install sensor facing up (Fig. 7). It can be
mounted either above or below sensor head.
Maximum allowed torque is 5 Nm.
It is recommended to insulate the sensor if the
thermostat is installed in a very cold place (< 5 °C).
o
r
f
m
r
e
a
n
c
e
Sensor holder
Fastener
p
t
s
e
B
Thermo paste
Fig. 6
Hot water su pply
Fig. 7
VD.C6.U4.02 | 3© Danfoss | 2018.07
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