ABB Navigator 550 Spares Replacement Procedures page 3

3.3 Replacing the constant-head assembly, pressure switch
assembly and pressure switch cable
Part numbers:

Constant-head assembly: AW503 075

Pressure switch assembly: AW503 077

Pressure switch cable: AW503 085
Referring to Fig. 3.5:
A
1. Remove all tubing
2. Carefully disconnect the 2 spade connectors
C
of pressure switch
3.1, page 2, for cable connection details and remove /
discard the cable.
3. Unscrew the 2 securing screws
constant head body support arms
constant-head assembly complete with pressure switch.
4. If replacing the pressure switch, unscrew the 4 retaining
F
screws (note that the nuts
support bracket and may fall out when screws are removed).
5. Fit a replacement pressure switch and new O-ring
reverse order of removal – note the orientation (LOW) is
always uppermost.
6. If replacing the cable, fit in the reverse order of removal and
connect the 2 spade connectors
pressure switch, otherwise re-connect the existing spade
connectors.
7. Secure the constant-head assembly, complete with pressure
switch, in the reverse order of removal.
Fig. 3.5 Replacing the constant-head assembly, pressure switch assembly
and pressure switch cable
to the constant-head assembly.
B
. If replacing the cable, refer to Section
D
on the upper faces of the
E
and remove the
G
are constrained in the
B
to the rear of the
3.4 Replacing the solenoid valve assembly and solenoid
valve cable
Part numbers:

Solenoid valve assembly: AW503 053

Solenoid valve cable: AW503 080
Referring to Fig. 3.6:
1. Remove all tubing connected to the valve
2. Unclip the valve cable connector
replacing cable(s), refer to Section 3.1 for cable connection
at the rear
details and remove / discard the cable.
3. Unscrew the 2 retaining screws
the bracket
D
plate
4. Unscrew the 2 valve securing screws and nuts
remove the valve.
5. Ensure the valve cable connector is facing downwards and fit
the new valve assembly to the plate
securing screws and nuts
6. Refit the plate
H
in the
C
screws
7. If replacing the cable, fit in the reverse order of removal and
re-clip the cable connector
valve body.
8. Reconnect all tubing to the new valve.
Fig. 3.6 Replacing the solenoid valve assembly and solenoid valve cable
Navigator 550 | Hydrazine wet-section| Spares replacement procedures | INF13/114–EN
3 Replacement procedures
B
C
that hold the plate
E
and withdraw the valve assembly
.
F
.
D E
to the bracket
.
B
to the underside of the new
IN/OUT
A
.
from the valve body. If
D
to
A
and
F
and
D
using the 2 valve
using the 2 retaining
3