Danfoss PCVPQ Operating guide [de]

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

2 Definition of Application ............................. 3

3 Description ........................................................... 4

3.1 Construction ..........................................................4

3.2 Mode of Operation ............................................4

4 Technical Data ................................................... 4

5 Scope of Delivery .............................................. 5

6 Assembly .............................................................. 6

6.1 Prior to Assembly ................................................ 6

6.2 Installation Position,

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

7.1 Required static Pressure, Pressure

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

7.8 Adjustment of

the Differential Pressure ................................14

7.9 Sealing ..................................................................14

7.10 Adjustement of

the Throttle Valves ...........................................14

7.11 Funstion Test ......................................................15

8 Trouble Shooting ...........................................16

9 Replacement of Valve,

Actuator, Trims ................................................ 17

2 | © Danfoss | 2016.05

9.1 Dismounting and Mounting

Actuator Valve ....................................................17

9.2 Replacement of Trim Valve VFQ 21 ............19

9.3 Dismounting, Mounting

Actuator AVP, AVP-F .........................................20

9.4 Replacement of

Trim Valve AVP, AVP-F .......................................20

VI.JA.H3.5B

Instructions PCVPQ

1 Safety Notes

observe these instructions.

Necessary assembly, start-up, 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.

MAINTENANCE

FREE

Prior to assembly and
commissioning to avoid injury
of persons and damages of the
devices, it is absolutely
necessary to carefully read and

2 Definition of

Application

The controller is used for flow rate limitation of
water for heating, district heating and cooling
systems.
The admissible medium temperatures depend
on the design and comprise 5-150 °C,
5-200 °C.

The technical data on the rating plates deter­mine the use.

VI.JA.H3.5B

© Danfoss | 2016.05 | 3

Instructions PCVPQ

P
(Diff

3 Description

3.1 Construction

ilot controller AVP

erential Pressure)

Throttling valve
only by DN150-250

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

Pilot controller AVP-F
(Flow Rate)

Adjusting throttle

Throttling element DE

Valve unit PCV-VFQ 21

Throttling valve

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

data sheet.

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VI.JA.H3.5B

Instructions PCVPQ

5 Scope of Delivery

DN 100-125

Assembly kit valve unit PCV-VFQ 21 Pilot controller DN 25

AVP

DN 25

Throttling element

Cu pipe Ø 6 × 1 × 1500 mm

Cu pipe Ø 10 × 1 × 3000 mm

AVP- F

DN 150-250

Assembly kit valve unit PCV-VFQ 21 Pilot controller DN 40

AVP

DN 40

Throttling element

Cu pipe Ø 6 × 1 × 1500 mm

Cu pipe Ø 10 × 1 × 3000 mm

AVP- F

VI.JA.H3.5B

© Danfoss | 2016.05 | 5

Instructions PCVPQ

6 Assembly 6.1 Prior to Assembly:

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.

6.2 Installation 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.

6.3 When 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.

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VI.JA.H3.5B

Instructions PCVPQ

Valve unit PCV - VFQ 21

lay impulse tube during mounting

250)

Pilot controller AVP-F

6 Assembly 6.6 Installation Scheme

Valve unit PCV - VFQ 21

Installation in the Return Line

Throttling valve

Throttling
element

Throttling valve

(only by DN 150 -

Bypass controller
PCVPQ

Installation in the Supply Line

Pilotregler AVP-F

Pilotregler AVP-F

Throttling valve

Throttling
element
Throttling valve
(only by DN 150 - 250)

Bypass controller

PCVPQ

VI.JA.H3.5B

© Danfoss | 2016.05 | 7

Instructions PCVPQ

CU pipe Ø 6 x 1

DN 25: pipe
Mater
(not

6 Assembly

6.7 Assembly Drawings, Dimensions

Lay when assembling.

to the return flow

to the supply flow

Install impulse tubes
laterally because of dir t

Cu pipe
Ø 10 x 1
Lay when assembling.

DN 100-125

Ø 33.7 x 3.2

ial: ST 35.8

part of the delivery)

Pilot controller AVP

Pilot controller
AVP-F

Throttling
element

DN 25 SW 50

8 | © Danfoss | 2016.05

VI.JA.H3.5B

Instructions PCVPQ

laterally because of dirt

CU pipe Ø 6 x 1

DN 40: pipe
Mater
(not part of the delivery)

6 Assembly

to the return flow

to the supply flow

Install impulse tubes

Lay when assembling.

Cu pipe
Ø 10 x 1
Lay when assembling.

DN 150-250

Ø 48.3 x 3.2

ial: ST 35.8

Dimensions

Nominal diameter DN 100 125 150 200 250

L1

350 400 480 600 730
H1 530 530 619 647 697
H2 - 245 300 325
D2 263 380

mm

D1 150 250 320 385 500

B 200 210 310 336 412

A ≥ 290 320 350 410

VI.JA.H3.5B

© Danfoss | 2016.05 | 9

Instructions PCVPQ

5

4

3

p2 p1

867

7 Start-up

7.1 Required Static Pressure, Pressure
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.

1

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:

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.

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.

2

1)

Pre-condi tion: Same pressure on both side s of the diaphragm.

If the pressure lo ad is one-sided, the (+)diaphragm cham ber
may have an excess p ressure of 1 bar in comparison to th e (-)
diaphragm chamber.

9

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

Required
flo

for the adjusting throttle

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.

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.

2

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

w rate

7. Re-screw the cap nut 1.

8. The cap nut can be sealed.

VI.JA.H3.5B

The flow rate adjustment is completed.
Now, adjust the differential pressure,
see section 7.8.

Read rotations

© Danfoss | 2016.05 | 11

Instructions PCVPQ

DN 100kvs 125/DN 125kvs 160/DN 150kvs 320

14

Rotations for the adjusting throttle

Flow rate (m

3

/h)

DN 100kvs 125/DN 125kvs 160/DN 150kvs 320

14

Rotations for the adjusting throttle

Flow rate (m

3

/h)

DN 200kvs 450/DN 250kvs 630

10

adjusting throttle: 4

required flow rate
limitation:

DN 200kvs 450/DN 250kvs 630

89

Rotations for the adjusting throttle

Flowrate (m

3

/h)

7 Start-up

7.7 Flow Adjusting Curves

140

p

=0,2



120

100

80

60

40

20

0

200

180

160

140

/h)

3

120

100

80

Flowrate (m

60

40

20

0

b

DN150

0123456789 10 11 12 13

DN 250

01234567 89

Rotations for the adjusting throttle

DN100/125

DN 200

p

=0,2



b

220

200

p

=0,5



b

180

DN 250

DN150

DN100/125

DN 200

p

=0,5



b

160

140

120

100

80

60

40

20

0

0123456789 10 11 12 13

260

240

220

200

180

160

140

120

100

80

60

40

20

0

012345 67

12 | © Danfoss | 2016.05

Example

Ventil DN 200

100 m³/h

necessary
rotations of the

VI.JA.H3.5B