16
Instruction Manual
4.3.2 Check Valves
Milton Roy recommends that check valve balls,
seats, gaskets, and O-rings be replaced on an
annual basis. If highly corrosive material (acids,
slurries etc.) is being pumped, some applications
may require more frequent replacement.
Milton Roy recommends an annual tune up using
a Routine Preventive Maintenance (RPM) Kit.
RPM kits contain replacements for those parts
which are subject to wear; specifically the ball
checks, check valve seats, gaskets/seals, and the
strainer. Replacing these parts annually with an
RPM kit can reduce the possibility of unexpected
downtime and will help to extend pump life.
To determine if check valves need maintenance,
disassemble the check valves following the
instructions in the following “Check Valve
Replacement” section. In valves that permit
disassembly, inspect the ball check and seat for
chemical or physical damage. The ball should be
perfectly round and free of pits, marks, or scratches.
The seat should retain a smooth edge where the
ball contacts for proper sealing. If the seat edge
is worn or damaged, or has any pits, marks, or
scratches, it should be replaced. If the ball and/
or seat is excessively damaged, the replacement
schedule should be shortened accordingly.
If the ball and seat are both in good condition, the
replacement schedule can be lengthened.
BEFORE CARRYING OUT ANY
SERVICING OPERATION ON THE
METERING UNIT OR PIPES, DISCONNECT ELECTRICAL
POWER FROM THE PUMP, AND TAKE THE NECESSARY STEPS
TO ENSURE THAT THE HARMFUL LIQUID THEY CONTAIN
CANNOT ESCAPE OR COME INTO CONTACT WITH
PERSONNEL. SUITABLE PROTECTIVE EQUIPMENT MUST BE
PROVIDED. CHECK THAT THERE IS NO SYSTEM FLUID
PRESSURE BEFORE PROCEEDING WITH DISMANTLING OF
LIQUID END COMPONENTS.
4.3.3 Cleaning Fouled Check Valves
Check valve assemblies are designed to be self
cleaning and should seldom need servicing.
Fouled check valves can usually be cleaned by
pumping a solution of mild detergent and warm
water (if compatible with liquid being pumped) for
15 minutes, followed by flushing with water.
4.3.4 Check Valve Replacement
Before beginning work on the valve assemblies,
make sure the shut- OFF valves are closed and
that pressure has been bled from the system. When
replacing the valves, take care to systematically
change their O-rings and/or gaskets. Take care to
properly assemble the valve assemblies. In valves
that permit replacement of ball and seat, the ball
must be placed on the sharp edge of the seats.
For each plunger size, check valves are supplied
in three different configurations: plastic- single
ball, plastic-double ball, and metallic- double ball.
Be sure to refer to the appropriate instructional set
below pertaining to your plunger size and valve
type.
BE SURE TO FOLLOW
INSTRUCTIONS CAREFULLY
AND REFER TO THE APPROPRIATE FIGURE WHEN
REASSEMBLING CHECK VALVES. IF CHECK VALVE
CARTRIDGES ARE INSTALLED INCORRECTLY, ONE OF THE
FOLLOWING WILL OCCUR: (A) IMMEDIATE SEVERE DAMAGE
TO PUMP MECHANISM, (B) NO PUMPING, (C) REVERSE
PUMPING ACTION (FROM DISCHARGE LINE INTO SUCTION
LINE).
SECTION 4 - MAINTENANCE
