97
e. Align the inlet check valve with its bore in the pump
head, as shown in Figure 7.39. Push the check valve,
along with its seal and backup ring, down into the
check valve bore.
f. Unscrew and withdraw the bolt, jam nut, and washer.
g. Install the two remaining inlet check valves in the same
manner.
3. Install the three (3) outlet check valves and three (3) high
pressure port towers as follows:
a. Install an o-ring seal and backup ring onto the high
pressure port tower, similar to that seen earlier in
Figure 7.38.
b. Install a bearing seal ring into the high pressure port
tower (seen in Figure 7.38).
c. Install a high pressure seal into the high pressure port
tower, over the bearing seal ring previously installed
(Figure 7.38).
d. Insert the 7/16”-20 bolt/jam nut/washer down through
the bore of the high pressure port tower and engage
the bolt threads with the internal threads of the outlet
check valve.
e. Snug the jam nut down against the washer to force the
end of the tower firmly against the backup ring of the
outlet check valve.
f. Lubricate an outlet check valve and tower with silicone
spray.
g. As shown in Figure 7.40, carefully align the check valve
and tower with the high pressure bore provided in the
pump head. Press the check valve and tower into the
bore.
h. Unscrew and withdraw the bolt, jam nut, and washer.
i. Install the two remaining outlet check valves and
towers in the same manner.
4. Press the thermal bypass actuator into its recess at the
center of the pump head. Check that the actuator is fully
seated. Make sure the small actuating stem is installed into
the actuator. A small dab of petroleum jelly will help hold
it in place.
Section 7 • Large Frame Pump
Portable Pressure Washer Familiarization and Troubleshooting Guide
Figure 7.39 - Inlet Check Valve Installation
Figure 7.40 - Outlet Check Valve Installation
