Valve Inspection and/or Replacement
Before removing and inspecting the valves, begin by
depressurizing and purging (if necessary) the unit and
refer to Appendix D.
Disassembly of 2 .75" Cylinder Size
1. Remove the valve cover plate and O-ring by removing
each of the three bolts.
2. After the cover plate and O-ring have been removed,
the valve assembly and valve gasket can be lifted out.
3. Inspect valves for breakage, corrosion, debris and
scratches on the valve plate. In many cases, valves
may simply be cleaned and reinstalled. If the valves
show any damage, they should be repaired or
replaced. Replacement is usually preferable although
repair parts are available. If valve plates are replaced,
seats should also be lapped until they are perfectly
smooth. If more than .005 of an inch must be removed
to achieve a smooth surface, the valve should be
discarded. If plates are replaced without re-lapping
the seat, rapid wear and leakage may occur.
Assembly of 2 .75" Cylinder Size
1. Insert metal valve gasket into the suction and/or
discharge opening of the head. The metal valve
gasket should always be replaced when the valve
is reinstalled.
2. Insert cleaned or new valve assembly. Make sure the
suction and discharge valves are in the proper suction
and discharge opening in the head.
3. Replace the O-ring and valve cover plate. Torque
the bolts to the value listed in Appendix B. NOTE:
Gaskets and O-rings are not normally reusable.
4. Check bolts after first week of operation. Re-torque if
necessary. See Appendix B for torque values.
Disassembly of 3 .25", 4", 5", 6" and 8"
Cylinder Sizes
1. Unscrew the valve cap and remove the O-ring.
2. Remove the valve cover plate, O-ring and holddown
screw by removing each of the four bolts. The
holddown screw is easily removed with the special
wrench supplied with the compressor.
3. After the cover plate and O-ring have been removed,
the valve cage, valve assembly and valve gasket can
be lifted out.
4. Inspect valves for breakage, corrosion, debris and
scratches on the valve plate. In many cases, valves
may simply be cleaned and reinstalled. If the valves
show any damage, they should be repaired or
replaced. Replacement is usually preferable although
repair parts are available. If valve plates are replaced,
seats should also be lapped until they are perfectly
smooth. If more than .005 of an inch must be removed
to achieve a smooth surface, the valve should be
discarded. If plates are replaced without re-lapping
the seat, rapid wear and leakage may occur.
Assembly of 3 .25", 4", 5", 6" and 8" Cylinder Sizes
1. Insert metal valve gasket into the suction and/or
discharge opening of the head. The metal valve
gasket should always be replaced when the valve
is reinstalled.
2. Insert cleaned or new valve assembly. Make sure the
suction and discharge valves are in the proper suction
and discharge opening in the head.
3. Insert the valve cage.
4. Replace the O-ring and valve cover plate. Torque the
bolts to the value listed in Appendix B. CAUTION: Be
sure the holddown screw has been removed.
5. To ensure the valve gasket is properly seated, insert
the holddown screw and tighten to the value listed
in Appendix B. NOTE: Gaskets and O-rings are not
normally reusable.
6. Replace the O-ring and valve cap and tighten to the
value listed in Appendix B.
7. Check bolts and valve holddown screws after first
week of operation. Re-torque if necessary. See
Appendix B for torque values.
5 .2 Heads
A horizontal compressor cylinder head or adjusting cap
seldom require replacement if the compressor is properly
maintained. The primary cause of damage to a cylinder
head and adjusting cap is corrosion and the entry of
solid debris or liquid into the compression chamber.
Improper storage can also result in corrosion damage to
the cylinder heads and adjusting caps (for proper storage
instructions see chapter 6).
Many compressor repair operations require removal
of the cylinder heads and adjusting caps. While the
compressor is disassembled, special care should be
taken to avoid damage or corrosion. If the compressor
is to be left open for more than a few hours, bare metal
surfaces should be coated with rust preventative.
When reassembling the compressor, make sure the
bolts are re-tightened to the torque values listed in
Appendix B.
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