551-E00 Page 5/6
MAINTENANCE
PREPARATION FOR DISASSEMBLY
1. Isolate Bypass Valve from liquids/vapor in inlet and
discharge lines, depressurize and purge any toxic,
flammable, corrosive or air hardening liquid/vapor.
2. Ensure the associated Pump Motor power supply has been
isolated, before proceeding with disassembly.
3. Once exposed to the atmosphere, immediately protect the
valve with from corrosion. A ¼ cup (60 mL) of diesel may
be poured into the valve
DISASSEMBLY
Refer to the Parts Designation drawings.
1. Unlock Adjusting Screw Locknut (10).
2. Release Spring pressure by rotating Adjusting Screw (8)
anti-clockwise.
3. Unscrew four Capscrews (9) holding Valve Cover (2) onto
Housing (1).
NOTE:
There will be a slight spring pre-
compression remaining.
4. Remove the Valve Cover (2) and O-Ring (2), together with
the Spring Cap (2) and its O-Ring (6).
5. Remove Spring Cap (2) and O-Ring (6) from Valve Cover
(2).
6. Remove Spring (5) and Valve (3a, 3b) from Housing (1).
7.
VRS OPTION ONLY:
Carefully remove Circlip (14) from
inside Valve (3a), then remove Ball (12) and Spring-Vent
(13).
INSPECTION
1. Inspect Housing (1) and valve bore for damage or wear. If
required, remove Housing and replace.
2. Check Valve (3a, 3b) for damage or wear. If required,
replace valve.
3. Inspect Spring - Bypass (5), replace if broken or damaged.
4. It is advised that O-Rings (6, 7) be replaced at every
overhaul.
5. Check Valve Cover (2), Spring Cap (4), Adjusting Screw (8)
and Locknut (10) for damage. Replace as required.
6.
VRS OPTION ONLY:
Check condition of Ball (12), Spring -
Vent (13) and Circlip (14). Replace as required.
REASSEMBLY
Refer to the Parts Designation drawings.
4.
VRS OPTION ONLY:
Insert Spring - Vent (13) into Valve
(3a) with large end seating in Valve, insert Ball (12) after
Spring - Vent and retain in place with Circlip (14), ensuring
Circlip locates correctly in groove.
5. Fit Valve (3a, 3b) into Housing (1), ensuring freedom of
movement.
6. Fit Spring - Bypass (5) on to top of Valve (3a, 3b).
7. Lightly smear all O-Rings (6, 7) with a compatible good
quality detergent free, light oil before assembly.
8. Fit O-Ring (7) to Valve Cover (2).
9. Fit O-Ring (6) to Spring Cap (4) and insert into Valve Cover
(2) with spring location boss facing out.
10.
Fasten Valve Cover (2) to Housing (1) using four
capscrews (9). Torque to 16 ft-lb (22 N-m).
11. After recommissioning, adjust differential pressure as per
‘BYPASS VALVE ADJUSTMENT’.