13
G25-991-2400A
H/G-25 Service (Fluid End)
3. Inspect and Replace
Diaphragms (22)
a. Lift the diaphragm by one edge, and turn the pump
shaft until the diaphragm pulls up. This will expose
machined cross holes in the valve plunger shaft behind
the diaphragm.
b. Insert an Allen wrench through one of the holes, to hold
the diaphragm up. The proper size tool is included in the
Wanner Tool Kit.
c. Remove the screw (19), O-ring (20), and follower (21) in
the center of the diaphragm.
d. Remove the diaphragm and inspect it carefully. A
ruptured diaphragm generally indicates a pumping
system problem, and replacing only the diaphragm will
not solve the larger problem. Inspect the diaphragm for
the following:
• Half-moon marks.Usually caused by cavitation of the
pump (refer to the “Troubleshooting” section).
• Concentric circular marks. Usually caused by
cavitation of the pump (refer to the “Troubleshooting”
section).
• Small puncture. Usually caused by a sharp foreign
object in the fluid, or by an ice particle.
• Diaphragm pulled away from the center screw or from
the cylinder sides. Usually caused by fluid being frozen
in the pump, or by overpressurization of the pump.
• Diaphragm becoming stiff and losing flexibility.
Usually caused by pumping a fluid that is incompatible
with the diaphragm material.
•
diaphragm is operated at temperatures below its rated
capability.
• Diaphragm edge chewed away. Usually caused by
overpressurizing the system.
f. Inspect the plunger (23) for any rough surfaces or edges.
Do not remove the plunger from the valve plunger (54).
Smooth the surfaces and edges as necessary with emery
cloth or a fine file.
CAUTION: If a diaphragm has ruptured and foreign
material or water has entered the oil reservoir, do
not operate the pump. Check all diaphragms, then
flush the reservoir completely (as outlined below)
and refill it with fresh oil. Never let the pump stand
with foreign material or water in the reservoir, or with
the reservoir empty.
g. Install a new diaphragm (or reinstall the old one, as
appropriate), ridge side out.
h. Clean the screw (19) and remove any oil from it. Apply
medium-strength threadlocker to the screw. Reinstall the
screw, the follower (21), and a new O-ring (20). Tighten
to 18 in.-lbs (2.0 N-m).
i. Repeat the above inspection procedure (and replacement,
if necessary) with the other two diaphragms.
4. Flush Contaminant from
Hydraulic End (only if a
diaphragm has ruptured)
a. Remove the oil drain cap (34) and allow all oil and
contaminant to drain out.
b. Fill the reservoir with kerosene or solvent, manually turn
the pump shaft to circulate the kerosene, and drain.
CAUTION: If you have EPDM diaphragms, or if food
grade oil is in the reservoir, do not use kerosene or
solvents. Instead, flush with the same lubricant that
is in the reservoir. Pumps with EPDM diaphragms
have an “E” as the 7th digit of the Model No.
c. Repeat the flushing procedure (step b).
d. Fill the reservoir with fresh oil, manually turn the pump
shaft to circulate the oil, and drain once again.
e. Refill the reservoir. If the oil appears milky, there is
still contaminant in the reservoir. Repeat the flushing
procedure until the oil appears clean.
5A. Prime the Hydraulic Cells on
Standard Pumps
a. With the pump horizontal, and the fluid-end head
removed, fill the reservoir with the appropriate Hydra-oil
for the application. Have a catch basin for oil that leaks
from behind the diaphragms when priming. Catch the oil
and dispose of it properly; do not reuse it.
b. All air in the oil within the hydraulic cell (behind the
diaphragms) must be forced out by turning the shaft (and
thus pumping the piston). A shaft rotator is included in the
Wanner Tool Kit. Turn the shaft until a bubble-free flow of
oil comes from behind all the diaphragms. Watch the oil
level in the reservoir; if it gets too low during priming, air
will be drawn into the pistons (inside the hydraulic end)
and will cause the pump to run rough.
c. Wipe excess oil from the cylinder casting (24) and
diaphragms (20).
d. Ensure that the oil is 1 inch (25 mm) from the top of the
fill port.
e. Replace oil fill cap (27).
5B. Priming the Hydraulic Cells
for Kel-Cell Pumps
NOTE: Providing oil prime to Kel-Cell fitted pumps requires
pressure be applied to the diaphragms. This can be
done manually, with the system head pressure, or with
pressurized air if available. Review all methods below to
determine the procedure most suitable.
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