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Instructions
7
Start-up
8
Pilot-controlled PCVQ DN 100 - DN 250 (PN 16, PN 25)
7.1 Required Static Pressure
The static pressure p1 in front of the controller
must not fall below 1.5 bar (excess pressure).
Non-observance may lead to cavitation and
damages in the throttling element 1.
p2
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
. For higher pressures, you
1)
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
2
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.
VI.JA.G2.02
© Danfoss 11/2006
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.
p1
1
This procedure guarantees that there is no
overturn of the diaphragm in the valve and the
actuators.
1. Open units 6 of the system.
2. Slowly open shut-off units in the supply
flow 7 and the return flow 8.
7
8
4
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.
To avoid too high pressure
differences on the controller,
observe the following sequence
when starting-up !
6
DH-SMT/SI
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