Danfoss PCVA User manual

© Danfoss | 2016.06 VI.JA.D2.5B | 1
Pressure relief controller PCVA,
Safety pressure relief controller PCVSAA
English Page 2
Instructions
Hilfsgesteuerters Überströmregler PCVA,
Hilfsgesteuertes Sicherheitsüberströmventil PCVSAA
Deutsch Seite 15
DN 100- DN 250
PN 16/PN 25
Einbau-, Bedienungsanleitung

Instructions PCVA, PCVSAA
2 | © Danfoss | 2016.06 VI.JA.D2.5B
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 ............................................6
6.3 When Installing 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 Tests...................................10
7.3 Filling the System ..............................................10
7.4 Start-up..................................................................10
7.5 Putting out of Operation ................................10
7.6 Adjustment of the Setpoint...........................11
7.7 Sealing ...................................................................11
7.8 Function Test.......................................................11
8 Trouble Shooting .................................. 12
8.1 Fault, Possible Cause, Remedy......................12
8.2 Diaphragm Break of the Controller SAVA. 12
9 Replacement of Valve, Actuator, Trim 13
9.1 Dismounting and Mounting Actuator and
Valve of the Valve Unit.....................................13
9.2 Replacement of Trim Valve VFG 21..............14
9.3 Dismounting, Mounting Actuator AVA,
SAVA........................................................................14
9.4 Replacement of Trim Valve AVA, SAVA ..... 14

Instructions PCVA, PCVSAA
© Danfoss | 2016.06 | 3
VI.JA.D2.5B
MAINTENANCE
FREE
1 Safety Notes
2 Definition of
Application
The controller is used for pressure control of
waterfor 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.
To avoid injury of persons and
damages to the device, it is
absolutely necessary to
carefully read and 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.

Instructions PCVA, PCVSAA
4 | © Danfoss | 2016.06 VI.JA.D2.5B
3.2 Mode of Operation
The control unit consists of the PCV-VFG21 valve
unit, installed in the main pipe, and the pressure
relief controller AVA or safety pressure relief
controller SAVA installed as pilot controller in the
bypass. In the bypass line, a throttle element is
installed in front of the pilot controllers.
As a pressure relief controller, the controller
keeps the pressure before the controller unit
in accordance with the preset setpoint on a
constant level.
As a safety pressure relief controller, the
controller guarantees that the pressure is not
exceeded before the control unit. If the controller
diaphragm is
damaged, the valve is closed via the second
diaphragm.The setpoint for the pressure is
adjusted by pre-stressing the setpoint spring of
the pilot controller.
The valve and the pilot valves are
pressurebalanced. The setpoint for the
pressure is adjusted by prestressing the
setpoint spring of the pilot controller. The
valve unit in the main pipe is opening on
rising pressure. The pilot controllers in the
bypass line are closing on rising pressure.
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 shockfree 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.
3 Description
4 Technical Data Technical data, see rating plates and the PCV
data sheet.
3.1 Construction
Throttling valve
Valve Unit PCV-
VFG21
Throttling element
Pilot controller SAVA
T
hrottling valve
only DN150-25
0

Instructions PCVA, PCVSAA
© Danfoss | 2016.06 | 5
VI.JA.D2.5B
5 Scope of Delivery
SAVA
SAVA
DN 100-125
Assembly kit valve unit PCV-VFG 21 Pilot controller DN 25
AVA
AVA
Cu pipe Ø 6 × 1 × 1500 mm
Cu pipe Ø 10 × 1 × 3000 mm
Throttling element
DN 150-250
Assembly kit valve unit PCV-VFG 21 Pilot controller DN 40
Throttling element
Cu pipe Ø 6 × 1 × 1500 mm
Cu pipe Ø 10 × 1 × 3000 mm
DN 25
DN 40

Instructions PCVA, PCVSAA
6 | © Danfoss | 2016.06 VI.JA.D2.5B
pin only
weld
do NOT
weld
1
2
Depressurized system before
any assembly work !
CAUTION!
6 Assembly 6.1 Prior to Assembly:
• 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 is only permitted in horizontal
pipelines with the actuators hanging in a
downward position.
6.3 When installing:
• Observe direction of flow.
• Design with welded ends:
• Loads on the valve body and the throttle
element by the pipes are not permitted.
6.4 Impulse Tube Installation
1. See installation scheme, section 6.6.
2. For CU pipes Ø 10 × 1, insert sockets 1on both
sides.
3. Care for correct position of the cutting rings 2.
6.5 Insulation
The diaphragm actuators must not be insulated
when insulating system parts.
4. Press impulse tube into the threaded fitting
up to its stop.
5. Tighten union nut, torque 40 Nm
6. Dismount again and check the position of the
cutting rings.

Instructions PCVA, PCVSAA
© Danfoss | 2016.06 | 7
VI.JA.D2.5B
T
hrottling valve
Throttling valve
(only by DN 150 - 250)
Throttling element
CU pipe Ø 10 × 1
Pilot controller SAVA
Do not install a
shut-o valve her.
But if you do so,
it is absolutely necessary
to secure against
unauthorized closing.
lay impulse tube during mounting
Valve unit
PCV - VFG 21
CU pipe Ø 10 × 1
T
hrottling valve
Throttling valve
(only by DN 150 - 250)
Throttling element
CU pipe Ø 10 × 1
Shut-o valve
Pilot controller AVA
CU pipe Ø 6 × 1
lay impulse tube during mounting
Valve unit
PCV - VFG 21
6 Assembly 6.6 Installation Scheme
Installation PCVA
Installation PCVSAA

Instructions PCVA, PCVSAA
8 | © Danfoss | 2016.06 VI.JA.D2.5B
-
Dismount impulse
tube
-
Unscrew threaded
fittings at the valve and
at the actuator
-
Close opening at the
valve with a stopper
(see assembly kit order
No. 003G1599)
Install impulse tubes
laterally because of dirt
Cu pipe Ø 6 × 1,
when laying,
use the assembly kit
order No. 003G1599
Cu pipe Ø 10 × 1
Lay when assembling.
D2
H1 H2
Valve unit PCV - VFG 21
DN 25: pipe Ø 33.7 × 3,2
Material: ST 35.8
(not part of the delivery)
Pilot controller
AVA
DN 25
SW 50 Throttling
element
L1
A
160
ca. 1000
75
159 244
these parts are not in the scope of delivery
6.7 Assembly Drawings, Dimensions
DN 100-125
6 Assembly

Instructions PCVA, PCVSAA
© Danfoss | 2016.06 | 9
VI.JA.D2.5B
- Dismount impulse tube
- Unscrew threaded
fittings at the valve and
at the actuator
- Close opening at the
valve with a stopper
(see assembly kit order
No. 003G1599)
Install impulse tubes
laterally because of dirt
Cu pipe Ø 6 × 1,
when laying,
use the assembly kit
order No. 003G1599
Cu pipe Ø 10 × 1
Lay when assembling.
D2
H1 H2
L1
these parts are not in the scope of delivery
DN 40: pipe Ø 48,3 × 3,2
Material: ST 35.8
(not part of the delivery)
290
D1
cca. 1200
200
these parts are not in the scope of delivery
A
B
Dimensions
Nominal diameter DN 100 125 150 200 250
L1
mm
350 400 480 600 730
H1 530 530 619 647 697
H2 -245 300 325
D2 263 380
D1 150 250 320 385 500
B200 210 310 336 412
A ≥ 290 320 350 410
DN 150-250
6 Assembly

Instructions PCVA, PCVSAA
10 | © Danfoss | 2016.06 VI.JA.D2.5B
76
3
4
2
5
9
8 10
6
7
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.
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 2is 25 bar 1). For higher pressures, you
must:
• Remove the impulse tubes 3.
The admissible operating excess pressure in the
actuator 4is 25 bar 1). For higher pressures, you
must:
• Remove the impulse tubes 5 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.
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 6is closed when no pressure is
applied and only opens with a defined flow in the
bypass.
The pilot controllers 7are closing on rising pressure.
Procedure
1. Open shut-off valves 8that possibly exist in
the impulse tubes.
2. Slowly open shut-off units first in the return
flow 9and then in the supply flow 10.
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.
p2 p1
1