18
5.2
Spool valve
5.2.1 Removal
For spool valve removal it is usually necessary to
unmount the valve controller from the actuator.
❑
Working from the bottom side of the valve con-
troller, unscrew the M4 screws (47, 3 pcs.).
Remove the spool valve cover (61) and the spool
valve (193) with gasket (174). Hold the ends of
the body with your fingers to avoid dropping the
spool from the body.
❑
Spool valve removal is only possible in the
spring-forced failsafe position of the spool. In the
case of a stuck spool it might be necessary to
remove the secondary diaphragm cover (167),
the spool spring (166) with its disc (164) and the
secondary diaphragm (162) with its plate. After
the removal of these parts it is possible to use a
punch to force the spool to the failsafe position.
❑
The spool valve may be cleaned if special atten-
tion is paid to a clean environment and proper
procedure.
❑
Clean the spool and the bore of the body with
care. Do not leave any fibres from cleaning mate-
rials in the bore or on the spool. Do not scratch
the mating surfaces of the spool and body.
5.2.2 Installation
❑
Ensure that the gaskets (174) and (63) are prop-
erly located in their grooves on the bottom of the
housing. Mount the spool valve and the spool
valve cover (61) to the housing, and tighten M4
screws evenly.
5.3
Flame arrestor assembly
The flame arrestor and the restrictor are fit into the same
plug which is located under the diaphragm cover (171).
This assembly can not be disassembled and should be
replaced if clogged.
❑
To remove the flame arrestor assembly, unscrew
the screws (173, 4 pcs) and remove the dia-
phragm cover (171) with its O-ring. Turn a M3
screw into the threaded hole of the flame arrestor
assembly to extract it from the housing. Installa-
tion is the reversal of removal. Place the O-rings
carefully.
5.4
Diaphragms
The diaphragms (169, 162) may be replaced by remov-
ing the respective covers (171, 167). The unit should be
unmounted from the actuator and the side to be worked
on turned upwards in order to avoid loss of small parts.
When replacing the secondary diaphragm (162), the
spool spring (166) with its guide (164) has to be
removed first. When reassembling, pay special attention
to the installation of the diaphragms and O-rings.
5.5
Communication circuit board
5.5.1 Removal
❑
Loosen the M8 stop screw (110) in the position
indicator (109) and turn the position indicator
from the shaft (11). Remove the inner cover (39)
attached with M3 screws (42, 3 pcs).
❑
Remove the M3 screws (217, 4 pcs.). Hold the
sides of the circuit board and lift it directly
upwards and outwards. Handle the board care-
fully, touching only the sides.
5.5.2 Installation
❑
Mount the new communication circuit board
carefully.
❑
Locate the pins with the matching connector on
the board. Tighten the M3 screws (217) evenly.
❑
Install the inner cover (39).
❑
Mount the position indicator (109) on the shaft
and tighten the M8 stop screw (110) temporarily.
The final orientation and locking of the position
indicator should be done after installation of the
valve controller to the actuator.
NOTE:
Each spool valve body has an individual correspond-
ing spool which cannot be replaced by any other
spool. Never alter the orientation of the spool. The ori-
entation of the spool is marked on the device, see
Fig. 21.
Fig. 21
Spool valve assembly
195
174 194
63
61
Sticker
NOTE:
Ground yourself on the body of the device before
touching the circuit board.
Содержание ND9200H
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