12 D10-991-2400 5/1/04
D/G-10 Service (Fluid End)
WRONG: Retainer
leg pointing toward
center of pump.
RIGH
Installing Valve Retainers
Into Valve Plate
2. Inspect Valves (10-15, 39)
*NOTE: For non-metallic slurry duty pumps, see the insert
to this manual for fluid valve service (Step 2), then proceed
to Step 3 in this manual for remaining service steps.
The three inlet and three outlet valve assemblies are identical
(but face in opposite directions). Inspect each valve as follows:
a. Check the spring retainer (15), and replace if worn.
Note: if your pump has either abrasive duty valve
assemblies or a non-metallic pump head there will be a
plastic dampening washer (39) at the bottom of each
seat. Inspect each one for wear or cracks and replace if
necessary.
b. Check the valve spring (13). If it is shorter than a new spring,
replace it (don’t just stretch the old spring).
c. Check the valve poppet (12). If worn excessively, replace it.
NOTE: If your pump has plastic spring retainers, there
is a tetra seal (flat O-ring, 14) between the retainer (15)
and valve seat (11).
d. Remove the valve seat (11). A seat remover is included in
the Wanner Tool Kit. Inspect the valve seat for wear, and
replace it if necessary.
e. Reinstall the valve assemblies:
• Clean the valve ports and shoulders with emery cloth,
and lubricate them with lubricating gel or petroleum jelly.
• Install the O-ring (10) on the valve seat (11).
• Inlet (3 center valves). Insert the spring retainer (15)
into the valve plate, then insert the spring, valve, and
valve seat (13,12,11).If the pump has plastic spring
retainers, a flat O-ring (14) goes between the retainer
and seat. Insert dampening washer (39) if included in
your valve assembly.
• Outlet (3 outer valves). Insert dampening washer (39)
if included in your valve assembly.Insert the valve seat,
valve, and spring, then the retainer. If the pump has
plastic retainers, install the flat O-ring between the
retainer and seat. If the pump has metal spring retainers
in the outlet valves, position them so a leg does not point
toward the center of the pump (refer to the illustration
below).
3. Inspect and Replace
Diaphragms (20)
If necessary to service the diaphragms, remove the two socket-
head cap screws (41) that secure the valve plate (16) to the
cylinder casting (24). Inspect the valve plate in the same manner
as you did the manifold.
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 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 (17), O-ring (18), and follower (19) 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.
• Slice in ridge of diaphragm. Occurs when a Viton
diaphragm is operated at cold temperatures.
• Diaphragm edge chewed away. Usually caused by
overpressurizing the system.
e. Inspect the plunger (21) for any rough surfaces or edges.
Do not remove the plunger from the plunger shaft. 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.
f. Install a new diaphragm (or reinstall the old one, as
appropriate), ridge side out.
g. Clean the screw (17) and remove any oil from it. Apply
medium-strength threadlocker to the screw. Reinstall the
screw and follower (19), and a new O-ring (18). Tighten to
18 in.-lbs (2.0 N-m).
h. Repeat the above inspection procedure (and replacement,
if necessary) with the other two diaphragms.
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