21
Instruction Manual
4.4 CORRECTIVE MAINTENANCE
4.4.1 3- Function Hydraulic Valve
The 3- function hydraulic valve assembly
(see Figure 8)
operates in filtered hydraulic oil
and should require maintenance only if unusual
circumstances occur, such as if corrosive media
contaminates the fluid.
Assembly and disassembly is straightforward.
Follow instructions in the “Start- Up of Pump
Containing No Oil in Casing and Displacement
Chamber” section of the manual. Field servicing
should be limited to inspection and cleaning only.
Repairs of this critical component should only be
carried out by an authorized Milton Roy repair
facility.
4.4.2 “MARS” Valve Assembly
The Mechanically Activated Refill System (MARS)
valve assembly
(see Figures 8 & 9)
requires no
periodic maintenance. Clean hydraulic oil is critical
for proper operation. Field servicing should be
limited to inspection and cleaning only. Repairs of
this critical component should only be carried out
by an authorized Milton Roy repair facility.
The valve is designed to be easily removed through
the front of the pump without having to remove
the displacement chamber. The following steps
describe the procedure for removal of the valve
from the displacement chamber
(refer to Figure 9)
:
A. Disassembly
1. Remove liquid end according to instructions
in the “Removing the Liquid End” portion of
the “
Diaphragm Replacement
” section of the
manual.
2. Insert a small tip screw driver into one of the two
small holes in the valve button (780) and gently
pry out plastic cap (790).
3. While pressing down on button (780), remove
the retaining ring (820) using the appropriate
retaining ring pliers (Waldes Truarc External
Type, Waldes Truarc part# M-1520).
4. Slide OFF activation button (780) and spring
(800).
5. Remove large retaining ring (810) using the
appropriate retaining ring pliers (Waldes Truarc
Internal Type, Waldes Truarc part# 0300).
6. Reinstall small retaining ring (820) in groove in
valve stem (770).
7. To avoid damage to valve stem, grip retaining
ring with pliers and pull remaining valve
assembly out of displacement chamber.
8. Discard O-rings (830,840) and retaining rings
(810, 820).
NOTE:
When reinstalling, make certain that new
O-rings and retaining rings are installed on
MARS assembly.
B. Reassembly
1. Install new O-rings (830, 840) on valve body
(750) and apply a light layer of O-ring grease
to O-rings.
2. Push assembly into place until it reaches stop
in displacement chamber.
3. Reinstall large bowed retaining ring (810).
Using a hammer and flat tipped screwdriver,
gently tap the ring to insure that it is securely
seated in the retaining groove machined into
the displacement chamber.
4. Reinstall spring (800) and activation button
(780).
5. While pressing button (780), reinstall small
retaining ring (820). Gently tap on the ring to
insure that it is securely seated in the retaining
ring groove machined into the valve stem
(770).
6. Press plastic cap piece (790) into activation
button (780).
7. Valve is now ready for service.
SECTION 4 - MAINTENANCE