Graco PT2500 - Manual (Page 18)

18 820-133
Service
Repairs, other than those for which instructions are given
below, should be performed by a trained and qualified re-
pair agency.
WARNING
To reduce the risk of injury, including fluid injection,
splashing in the eyes or on the skin, or injury from
moving parts, always follow the Pressure Relief
Procedure Warning on page 11 before checking or
repairing any part of the spray system.
Inlet Check Valve. See Fig. 15.
1. Unscrew the inlet check valve (26) from the paint
pump (22).
2. Clean the gasket (26a), the inlet valve (26), and the
paint pump (22) threads and check for erosion. If any
of the parts are eroded, replace them.
3. Be sure the threads in the paint pump are clean.
4. Lubricate the threads of the inlet valve with petro-
leum jelly. Install the gasket on the valve, then install
the valve and torque it to 320–360 in–lb (36–41 N.m).
Outlet Check Valve. See Fig. 15.
1. Unscrew the plug (28d) and the housing (28b).
2. Use a pick, such as a dentist’s pick, to remove the
seal (28a) from the paint pump (23). The seal may be
hard to remove.
DO NOT LEAVE THE SEAL IN THE
PAINT PUMP HOUSING.
3. Clean the parts thoroughly, including the threads in
the pump, with a compatible solvent. Check all parts
for wear or damage and replace as needed.
4. Lubricate the threads of the housing (28b) and plug
(28d).
5. Install a NEW seal (28a) in the pump housing. AL-
WAYS replace the seal (28a). Do not try to reuse the
old seal as it will be deformed.
CAUTION
Be sure you do not install a new seal until the old one
is removed. Having two seals in the valve will cause
performance problems.
6. Install the housing (28b) and torque to 125–150 in–lb
(14–17 N.m).
7. The last coil on one end of the spring is turned in.
Place this end over the stud in the plug (28d). Install
the ball (28e), washer (28f) and plug, and torque to
plug to 380–300 in–lb (32–34 N.m).
Pressure Control. See Fig. 15.
When removing the pressure control (4) to check or clean
it, always replace the seal (4a). When replacing the pres-
sure control, torque the new control (4) to 125–150 in–lb
(14–17 N.m).
Starter Switch. See Fig. 15.
Remove the cover of the switch box. Remove the two
screws holding the starter switch (18a). Remove the old
switch and install a new one.
Diaphragm. See Fig. 15.
1. Remove the inlet strainer (27). Remove the four paint
pump screws (25) and lockwashers (24).
2. Remove the bypass valve (66) and the fluid outlet
nipple (67), and then remove the screws (35) and
shield (3).
3. Remove the screw (36) and lockwasher (37) from the
bracket (38).
4. Pull the paint pump assembly away from the hydrau-
lic housing (20) and remove the old diaphragm (21).
CAUTION
Never start the electric motor with the inlet valve (26)
removed to avoid damaging the diaphragm.
CAUTION
Be careful not to get any dirt or paint on the new dia-
phragm or the hydraulic housing. Contaminants in
the hydraulic system can cause the sprayer to mal-
function and result in costly damage to the sprayer.
DO NOT TAMPER with the nut (C). The nut is factory
set to hold the spring to a specific dimension.
5. Check the gasket (22a) for wear or damage and re-
place it if needed. Clean the top of the paint pump
and the hydraulic housing thoroughly.
6. Install the new diaphragm assembly (21), lubricate
the internal threads of the housing (20), and reas-
semble the parts.