18
phragm are replaced. For convenience, these parts
are available in a Routine Preventative Mainte-
nance (RPM) Kit from your local representative.
RPM kit numbers are listed in Section 1, Paragraph
1.6.
4.5 SEMI ANNUAL OIL CHANGE
The oil in the main housing should be drained twice
a year, using the drain plug provided, and new oil
installed. This can usually be scheduled to coincide
with the change from winter to summer grade lubri-
cants and vice versa. Refer to “Pump Lubricants” in
Section 2, Installation, Paragraph 2.8 for informa-
tion on recommended oil and oil capacity.
NOTE: When adding oil, pour in a thin, slow
stream to avoid overflow.
4.6 CHECK VALVE CARTRIDGES
Milton Roy Company recommends that check
valves be replaced on an annual basis. If highly
corrosive material (acids, slurries, etc.) is being
pumped, some applications may require more fre-
quent replacement.
In general, poor or reduced pump performance
indicates that the check valves need to be replaced
(refer to Section 5, Troubleshooting).
Complete instructions for replacing worn check
valve assemblies is given in the “Corrective Main-
tenance” section.
The mRoy check valves are complete assemblies
manufactured at the factory and should not be dis-
assembled in the field.
To determine if the check valves need replace-
ment, with the pump off and pressure removed
from system unscrew the check valve from the liq-
uid end and peer through the hole in the check
valve seat. The ball should appear perfectly round
and free of pits, mars, or scratches. 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.
4.7 DIAPHRAGM(S)
The mRoy PTFE diaphragm is extremely durable
and often lasts for many years. As a preventative
measure, however, Milton Roy Company recom-
mends that the mRoy diaphragm be replaced
yearly to coincide with check valve replacement.
Also whenever the head is removed freeing the
diaphragm the diaphragm must be replaced. Refer
to the instructions in the “Corrective Maintenance”
section for diaphragm replacement.
4.8 CORRECTIVE MAINTENANCE
BEFORE CARRYING OUT ANY SERVIC-
ING OPERATION ON THE METERING
UNIT OR PIPES, DISCONNECT ELEC-
TRICAL POWER FROM THE PUMP.
TAKE THE NECESSARY STEPS TO
ENSURE THAT ANY HARMFUL LIQUID
IN THE PUMP OR PIPING SYSTEM CAN-
NOT ESCAPE OR COME INTO CON-
TACT WITH PERSONNEL. SUITABLE
PROTECTIVE EQUIPMENT MUST BE
PROVIDED. CHECK THAT THERE IS NO
PRESSURE BEFORE PROCEEDING
WITH DISMANTLING.
4.8.1 XT & XW Diaphragm Replacement
NOTE: This section contains procedures for
disassembly and assembly of the pump, and
check valves, plus procedures for preventive
and corrective maintenance. To maintain the
reliability, durability, and performance of your
pump assembly and related components, it is
essential to follow these procedures exactly
and carefully.
For consistent, reliable performance, replace any
O-rings, or other seals that you remove. Order
replacement seal kits with detailed instructions
from your Milton Roy Company. Whenever you dis-
connect any fluid piping, cover all open ports in the
pump assembly to prevent dirt from entering.
Disassembly
1. Remove drain plug (XT, Item 350, Figure 9,
10, 11 or XW, Item 60, Figure 14) at bottom
of pump housing, and drain pump of all oil.
2. Using appropriate wrenches, remove
suction check valve (XT, Item 240, Figure 8
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