AVPQ Di Erential Pressure and Flow Controller
Instructions AVPQ, AVPQ-F, AVPQ 4, AVPQT – PN 16,25 / DN 15 – 50
Differential pressure and flow controller
AVPQ, AVPQ-F, AVPQ 4, AVPQT
Page 2
www.danfoss.com
Safety Notes
Prior to assembly and commisioning to avoid injury of persons and damages of the devices, it is absolutely necessary to carefully read and observe these instructions.
Necessary assembly, startup, and maintenance work must be performed only by qualified, trained and authorized personnel.
Prior to assembly and maintenance work on the controller, the system must be:
– depressurized,
– cooled down,
– emptied and
– cleaned.
Please comply with the instructions of the system manufacturer or system operator.
Definition of Application
The controller is used for differential pressure and flow (and temperature at AVPQT) control of water and water glycol mixtures for heating, district heating and cooling systems.
The technical parameters on the product labels determine the use.
Assembly
Admissible Installation Positions
Medium temperatures up to 100 °C:
– Can be installed in any position.
Medium temperatures
> 100 °C:
– Installation permitted only in horizontal pipelines with the actuator oriented downwards.
Installation Location and
Installation Scheme
1 AVPQ(-F) return mounting
2 AVPQ 4 flow mounting
3 AVPQT return mounting
Valve Installation
1. Clean pipeline system
prior to assembly.
2. The installation of a strainer
in front of the controller is
strongly recommended 1.
3. Install pressure indicators
in front of and behind
the system part to be
controlled.
4. Install valve
• The flow direction
indicated on the product
label 2 or on the valve
must be observed 3.
• The valve with mounted
weld-on taipieces may
only be spotwelded to the
pipeline 4.
The weld-on taipieces may
be welded only without
the valve and seals! 5 6
If these instructions
are not observed, high
welding temperatures may
destroy the seals.
• Flanges 7 in the pipeline
must be in parallel
position and sealing
surfaces must be clean
and without any damage.
Tighten screws in flanges
crosswise in 3 steps up
to the maximum torque
(50 Nm).
5. Caution:
Mechanical loads of
the valve body by
the pipelines are not
permitted.
Mounting of temperature actuator
(relevant only at AVPQT controllers)
Place temperature actuator
AVT at the combination piece
and tighten union nut with
wrench SW 50.
Torque 35Nm.
Other details:
See instructions for
temperature actuator AVT.
Impulse tube mounting
• Which impulse tubes to use?
Use Impulse tube set AV 1
or use followinge pipe:
Copper Ø 6×1 mm
EN 12449
• Connection of impulse
tube 1 in the system
Return mounting 2
Flow mounting 3
• Connection to the pipeline
It is strongly
recommended to install
the impulse tube to the
pipeline horizontally 2
or upwards 1.
This prevents dirt
accumulation in the
impulse tube and possible
malfunction of the
controller.
Connection downwards is
not recommendable 3.
• Impulse Tube Mounting
1. Cut pipe perpendicularly
to the pipe axis and
smooth edges out 1.
2. Press impulse tube 2
into the threaded joint
up to its stop.
3. Tighten union nut 3
Torque 14 Nm
Insulation
For medium temperatures
up to 100 °C the pressure
actuator 1 may also be
insulated.
Dimensions, Weights
- Conical ext. thread acc. to
EN 10226-1 - Flanges PN 25, acc. to
EN 1092‑2
Start-up
Filling the system, first
start-up
- Slowly open shut-off
valves 1 that are possibly
available in the impulse
tubes. - Open valves 2 in the
system. - Slowly open shut-off
devices 3 in the flow
pipeline. - Slowly open shut-off
devices 4 in the return
pipeline.
Leak and Pressure Tests
Before pressure test, open the
adjustable flow restrictor 2
by turning it to the left
(counter clockwise).
Pressure must be gradually
increased at the
+/- connection 1.
Non-compliance may cause
damages at the actuator or
the valve.
A pressure test of the entire
system must be carried
out in accordance with
manufacturer’s instructions.
The maximum test pressure
is:
1.5 x PN
PN – see product label
Putting out of operation
1. Slowly close shut-off
devices 1 in the flow
pipeline.
2. Slowly close shut-off
devices 2 in the return
pipeline.
Settings
First set the differential
pressure.
Differential Pressure
Setting
(not relevant at fixed setting
version AVPQ-F)
The diff. pressure setting
range is indicated on the
product label 1.
Procedure:
1. Unscrew cover 2.
2. Loosen counter nut 3.
3. Unscrew
(counter‑clockwise)
adjustable flow
restrictor 4 up to its stop.
4. Start system,
see section “Filling the
system, first start-up“
Completely open all shutoff
devices in the system.
5. Set flow rate on a
motorised valve 1, on
which differential pressure
is controlled, to about
50 % .
6. Adjustment
Observe pressure
indicators 4 or/and
alternatively see handle
scale indication.
Turning to the right 2
(clockwise) increases the
set-point (stressing the
spring).
Turning to the left 3
(counter-clockwise)
reduces the set-point
(releasing the spring).
Note:
If the required differential
pressure is not attained, a
cause may be a too small
pressure loss in the system.
Seal
The set-point adjuster can
be sealed by a seal wire 1, if
neccessary.
Flow Rate Setting
The flow rate is adjusted
by means the setting of
adjustable flow restrictor 1.
There are two possibilities:
1. Adjustment with the flow
adjusting curves,
2. Adjustment with heat
meter, see page 19.
Pre-condition
(min. diff. pressure over the valve)
At the maximum flow rate,
the pressure difference Δpv
across the control valve must
be at least: Δpmin = 0.5 bar
Adjustment with flow adjusting curves
The system don’t need to be
active for being adjusted.
1. Unscrew cover 1, loosen
counter nut 2.
2. Screw (clockwise)
adjustable flow
restrictor 3 in up to its
stop.
Valve is closed, no flow.
3. Select flow adjusting curve
in the diagram (see next
page).
4. Unscrew (counterclockwise)
the adjustable
flow restrictor by
determined number of
revolutions 4.
5. Adjustment is completed,
continue with step 3,
page 19.
Note:
The setting may be verified
with help of a heat meter if the
system is in operation, see next
section.
Flow Adjusting Curves
Adjustment with Heat Meter
Pre-condition:
The system must be in
operation. All units in the
system 1 or a bypass must
be completely open.
1. Unscrew cover 2, loosen
counter nut 3.
2. Observe heat meter
indicator.
Turning to the left
(counter-clockwise) 4
increases the flow rate.
Turning to the right
(clockwise) 5 reduces the
flow rate.
After the adjustment has
been completed:
3. Tighten counter nut 6.
4. Screw the cover 7 in and
tighten.
5. Cover may be sealed.
Temperature setting
(relevant only at AVPQT
controllers)
See instructions for
temperature actuator AVT.
Documents / Resources
 |
Danfoss AVPQ Di Erential Pressure and Flow Controller [pdf] Instruction Manual AVPQ Di Erential Pressure and Flow Controller, AVPQ, Di Erential Pressure and Flow Controller, Pressure and Flow Controller, Flow Controller, Controller |
