Instructions
Pilot-controlled Flow Rate and Differential Pressure
Controller PCVPQ
English |
Page 2 |
Instructions
Hilfsgesteuerter Volumenstrom-, Differenzdruckregler
PCVPQ
Deutsch |
Page 21 |
DN 100 - DN 250
PN 16 / PN 25
© Danfoss | 2016.05 |
VI.JA.H3.5B | 1 |
Instructions |
PCVPQ |
Table of Contents |
1 |
Safety Notes ........................................................ |
3 |
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2 |
Definition of Application ............................. |
3 |
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3 |
Description........................................................... |
4 |
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3.1 |
Construction.......................................................... |
4 |
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3.2 |
Mode of Operation ............................................. |
4 |
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4 |
Technical Data .................................................... |
4 |
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5 |
Scope of Delivery............................................... |
5 |
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6 |
Assembly ............................................................... |
6 |
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6.1 |
Prior to Assembly ................................................ |
6 |
6.2Installation Position,
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Installation Place .................................................. |
6 |
6.3 |
When Installaling observe ............................... |
6 |
6.4 |
Impulse Tube Installation.................................. |
6 |
6.5 |
Insulation ................................................................ |
6 |
6.6 |
Installation Scheme............................................. |
7 |
6.7 |
Assembly Drawings, Dimensions .................. |
8 |
7 |
Start-up................................................................. |
10 |
7.1Required static Pressure, Pressure
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Difference ............................................................. |
10 |
7.2 |
Leak and Pressure Test..................................... |
10 |
7.3 |
Filling the System............................................... |
10 |
7.4 |
Start-up.................................................................. |
10 |
7.5 |
Putting out of Operation................................. |
10 |
7.6 |
Flow Rate Adjustment...................................... |
11 |
7.7 |
Flow Adjusting Curves ..................................... |
12 |
7.8Adjustment of
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the Differential Pressure ................................. |
14 |
7.9 |
Sealing ................................................................... |
14 |
7.10 |
Adjustement of |
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the Throttle Valves ............................................ |
14 |
7.11 |
Funstion Test ....................................................... |
15 |
8 |
Trouble Shooting ............................................ |
16 |
9 |
Replacement of Valve, |
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Actuator, Trims ................................................. |
17 |
9.1 |
Dismounting and Mounting |
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Actuator Valve .................................................... |
17 |
9.2 |
Replacement of Trim Valve VFQ 21 ............. |
19 |
9.3Dismounting, Mounting
Actuator AVP, AVP-F |
.........................................20 |
9.4 Replacement of |
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Trim Valve AVP, AVP-F |
.......................................20 |
2 | © Danfoss | 2016.05 |
VI.JA.H3.5B |
Instructions |
PCVPQ |
1 |
Safety Notes |
MAINTENANCE
FREE
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Prior to assembly and |
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commissioning to avoid injury |
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of persons and damages of the |
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devices, it is absolutely |
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necessary to carefully read and |
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observe these instructions. |
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Necessary assembly, start-up, and maintenance |
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work must be performed only by qualified, |
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trained and authorized personnel. |
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Prior to assembly and maintenance work on the |
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controller, the system must be: |
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depressurized, |
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cooled down, |
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emptied and |
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cleaned. |
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Please comply with the instructions of the |
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system manufacturer or system operator. |
2 |
Definition of |
The controller is used for flow rate limitation of |
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Application |
water for heating, district heating and cooling |
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systems. |
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The admissible medium temperatures depend |
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on the design and comprise 5-150 °C, |
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5-200 °C. |
The technical data on the rating plates determine the use.
VI.JA.H3.5B |
© Danfoss | 2016.05 | 3 |
Instructions |
PCVPQ |
3 |
Description |
3.1 Construction |
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Pilot controller AVP |
Pilot controller AVP-F |
Adjusting throttle |
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(Differential Pressure) |
(Flow Rate) |
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Throttling element DE |
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Valve unit PCV-VFQ 21 |
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Throttling valve |
Throttling valve |
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only by DN150-250 |
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3.2 Mode of Operation
The control unit consists of the PCV-VFQ21 valve unit, installed in the main pipe, and the differential pressure controllers AVP and AVP-F installed as pilot controllers in the bypass. In the
bypass line, a throttle element is installed in front of the pilot controllers.
The controller keeps the differential pressure for the corresponding section on a constant level and restricts the flow rate to the adjusted setpoints.
The valve and the pilot valves are pressurebalanced.
The setpoint for the differential pressure is adjusted by pre-stressing the setpoint spring of the pilot controller AVP. The setpoint for the flow rate limitation is adjusted at the adjusting throttle of the valve unit.
The valve unit in the main pipe is opening on rising pressure. The pilot controllers in the bypass line are closing on rising pressure.
Differential Pressure Control
In case of small flow rates, the valve in the main pipe remains closed through the pressure spring
in the actuator of the valve unit. The pressure is exclusively controlled by the pilot controller.
If the flow rate in the bypass is increased, the pressure in the throttle element (Venturi nozzle) decreases.
The reduced pressure acts through an impulse tube upon the lower chamber of the actuator of the valve unit. The main valve is thus opened shock-free and continuously.
If the flow rate is reduced, the pressure in the throttle element raises and the main valve closes. This sequential switching guarantees an operation free of vibrations and a small control deviation over a wide positioning range.
Flow Rate Limitation
If the flow rate reaches the adjusted setpoint, the differential pressure increases at the adjusting throttle. This differential pressure acts on the actuator AVP-F via the impulse tubes and the valve AVP-F closes. Consequently, the valve of the valve unit is throttled, too, and the flow rate is restricted.
4 |
Technical Data |
Technical data, see rating plates and the PCV |
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data sheet. |
4 | © Danfoss | 2016.05 |
VI.JA.H3.5B |
Instructions |
PCVPQ |
5 Scope of Delivery |
DN 100-125 |
Assembly kit valve unit PCV-VFQ 21 |
Pilot controller DN 25 |
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AVP |
AVP-F |
DN 25 |
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Throttling element
Cu pipe Ø 6 × 1 × 1500 mm
Cu pipe Ø 10 × 1 × 3000 mm
DN 150-250
Assembly kit valve unit PCV-VFQ 21 |
Pilot controller DN 40 |
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AVP |
AVP-F |
DN 40 |
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Throttling element
Cu pipe Ø 6 × 1 × 1500 mm
Cu pipe Ø 10 × 1 × 3000 mm
VI.JA.H3.5B |
© Danfoss | 2016.05 | 5 |
Instructions |
PCVPQ |
6 |
Assembly |
6.1 Prior to Assembly: |
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Depressurized system before any assembly work !
CAUTION!
•Clean pipeline system.
•Install strainer in front of the controller.
•Install shut-off units in front of and behind the controller.
6.2Installation Position, Installation Place
•Installation is only permitted in horizontal pipelines with the actuators hanging in a downward position.
•The controller may be installed in the supply as well as in the return line.
6.3When installing:
•Observe direction of flow.
•Design with welded ends:
6.4 Impulse Tube Installation
See installation scheme, section 6.6.
For CU pipes Ø 10 × 1, insert sockets 1 on both sides.
1
Care for correct position of the cutting rings 2.
2
pin only
weld
do NOT weld
•Loads on the valve body and the throttle element by the pipes are not permitted.
6.5 Insulation
The diaphragm actuators must not be insulated when insulating system parts.
6 | © Danfoss | 2016.05 |
VI.JA.H3.5B |
Instructions |
PCVPQ |
6 |
Assembly |
6.6 Installation Scheme |
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Throttling valve |
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Throttling |
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element |
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Valve unit PCV - VFQ 21 |
Throttling valve |
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(only by DN 150 - 250) |
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Bypass controller |
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PCVPQ |
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Pilot controller AVP-F |
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Installation in the Return Line |
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Valve unit PCV - VFQ 21
Throttling valve
Throttling element
Throttling valve
(only by DN 150 - 250)
Bypass controller
PCVPQ
Pilotregler AVP-F |
Pilotregler AVP-F |
lay impulse tube during mounting
Installation in the Supply Line
VI.JA.H3.5B |
© Danfoss | 2016.05 | 7 |
Instructions |
PCVPQ |
6 |
Assembly |
6.7 Assembly Drawings, Dimensions |
CU pipe Ø 6 x 1
Lay when assembling.
to the return flow |
Cu pipe |
to the supply flow |
Ø 10 x 1 |
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Lay when assembling. |
Install impulse tubes |
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laterally because of dirt |
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Pilot controller AVP |
Pilot controller |
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DN 25 SW 50 |
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AVP-F |
Throttling |
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element |
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DN 25: pipe Ø 33.7 x 3.2 Material: ST 35.8
(not part of the delivery)
DN 100-125
8 | © Danfoss | 2016.05 |
VI.JA.H3.5B |
Instructions |
PCVPQ |
6 |
Assembly |
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CU pipe Ø 6 x 1 |
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Lay when assembling. |
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to the return flow |
to the supply flow
Cu pipe Ø 10 x 1
Lay when assembling.
Install impulse tubes laterally because of dirt
DN 40: pipe Ø 48.3 x 3.2 Material: ST 35.8
(not part of the delivery)
DN 150-250
Dimensions
Nominal diameter DN |
100 |
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125 |
150 |
200 |
250 |
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L1 |
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350 |
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400 |
480 |
600 |
730 |
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H1 |
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530 |
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530 |
619 |
647 |
697 |
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H2 |
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245 |
300 |
325 |
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D2 |
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263 |
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380 |
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D1 |
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150 |
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250 |
320 |
385 |
500 |
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B |
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200 |
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210 |
310 |
336 |
412 |
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A ≥ |
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290 |
320 |
350 |
410 |
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VI.JA.H3.5B |
© Danfoss | 2016.05 | 9 |
Instructions |
PCVPQ |
7 |
Start-up |
7.1 Required Static Pressure, Pressure |
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Difference |
For a proper functioning, a minimum pressure difference of p1 - p2 ≥ 0.5 bar is required.
The static pressure p1 in front of the controller must not fall below 1.5 bar (excess pressure). Nonobservance may lead to cavitation and damages in the throttling element 1.
p2 |
p1 |
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7.2 Leak and Pressure Tests
To avoid too high pressures at the diaphragm actuators, the following should be observed prior to any pressure tests:
Actuator of valve unit:
The admissible operating excess pressure in the actuator 2 is 25 bar 1). For higher pressures, you must:
•Remove the impulse tubes 3 at the actuator and close the connections with a stopper.
•Prior to any leak or pressure test, the instructions in section 7.3 must be complied with.
5 |
4 |
2 |
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3 |
1)Pre-condition: Same pressure on both sides of the diaphragm. If the pressure load is one-sided, the (+)diaphragm chamber may have an excess pressure of 1 bar in comparison to the (-) diaphragm chamber.
7.3 Filling the System
Note:
The controller 4 is closed when no pressure is applied and only opens with a defined flow in the bypass.
The pilot controller 5 is closing on rising pressure.
To avoid too high pressure differences on the controller, observe the following sequence
when starting-up !
This procedure guarantees that there is no overturn of the diaphragm in the valve and the actuators.
1.Open shut-off valves 6 that possibly exist in the impulse tubes.
2.Open units 7 of the system.
3.Slowly open shut-off units in the supply flow 8 and the return flow 9.
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6 |
7 |
9 |
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7.4 Start-up
During starting-up the filled system, open the units in the same sequence as described in section 7.3.
7.5 Putting out of operation
When putting the system out of operation, first close the shut-off units in the supply flow and then those of the return flow.
10 | © Danfoss | 2016.05 |
VI.JA.H3.5B |
Instructions |
PCVPQ |
7.6 Flow Rate Adjustment
The setting of the setpoint for the flow rate limitation is made by means of flow adjusting curves (see section 7.7) or a heat meter (see page 33).
Adjustment by means of flow adjusting curves
Adjustment is to be made at a shut-down system.
Procedure
1. Unscrew cover 1.
1
2. Loosen the counter nut 2.
2
4.Turn the adjusting throttle by this number of rotations to the left.
5.The adjusted flow rate can be verified by means of a flow rate measuring device. Perhaps you need to re-adjust the flow rate.
Care for an adequate differential pressure in the system.
6.Tighten the counter nut without changing the position of the adjusting throttle.
7. Re-screw the cap nut 1.
2. Screw in the adjusting throttle 3 to its stop.
3
3.Choose diagram,
(see section 7.7, Flow Adjusting Curves)
Observe effecitve pressure Δpb: 0.2 or 0.5 bar see rating plate on the actuator AVP-F
Required flow rate
Read rotations
for the adjusting throttle
8. The cap nut can be sealed.
The flow rate adjustment is completed. Now, adjust the differential pressure, see section 7.8.
VI.JA.H3.5B |
© Danfoss | 2016.05 | 11 |
Instructions |
PCVPQ |
7 Start-up
7.7 Flow Adjusting Curves
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DN 100 kvs 125 / DN 125 kvs 160 / DN 150 kvs 320 |
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140 |
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220 |
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pb=0,2 |
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200 |
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120 |
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180 |
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100 |
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DN150 |
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160 |
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<![if ! IE]> <![endif]>(m3/h) |
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<![if ! IE]> <![endif]>(m3/h) |
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140 |
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80 |
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120 |
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<![if ! IE]> <![endif]>rate |
100 |
<![if ! IE]> <![endif]>low |
60 |
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<![if ! IE]> <![endif]>low |
80 |
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<![if ! IE]> <![endif]>F |
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<![if ! IE]> <![endif]>F |
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40 |
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60 |
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DN100 / 125 |
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40 |
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20 |
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20 |
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DN 100 kvs 125 / DN 125 kvs 160 / DN 150 kvs 320 |
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pb=0,5 |
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DN150 |
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DN100 / 125 |
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14 |
Rotations for the adjusting throttle |
Rotations for the adjusting throttle |
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DN 200 kvs 450 / DN 250 kvs 630 |
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DN 200 kvs 450 / DN 250 kvs 630 |
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200 |
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260 |
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180 |
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240 |
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DN 250 |
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220 |
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160 |
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DN 250 |
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200 |
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<![if ! IE]> <![endif]>F low rate (m3/h) |
140 |
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180 |
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120 |
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<![if ! IE]> <![endif]>low rate (m3/h) |
160 |
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DN 200 |
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DN 200 |
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60 |
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pb=0,2 |
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pb=0,5 |
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Rotations for the adjusting throttle |
Rotations for the adjusting throttle |
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Example
Ventil DN 200
required flow rate |
necessary |
limitation: 100 m³/h |
rotations of the |
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adjusting throttle: 4 |
12 | © Danfoss | 2016.05 |
VI.JA.H3.5B |