DISPLACEMENT PUMP

WARNING

To reduce the risk of serious bodily injury, follow the Pressure Relief Procedure Warning on page 16 before checking or repairing any part of the spray system. Unplug the sprayer!

Removing the Pump. See Fig 18±1.

1.Flush the sprayer. Relieve pressure.

2.For the upright sprayer, remove the clips (110,114) and drain tube (125) from the pump.

3.Hold the intake valve (222) steady with a wrench and unscrew the adapter (38).

4.Unscrew the hose (52).

5.Use a screwdriver to push the retaining spring (33) aside, and then push out the pin (34).

6.Loosen the locknut (112) and unscrew the pump (58).

55

54

A

33

36

34

WARNING

Be sure the retaining spring (33) is firmly and com- pletely in the groove of the connecting rod to prevent the pin (34) from working loose due to vibration. See Fig 18±1.

If the pin works loose, it or other parts could break off due to the force of the pumping action. These parts could be projected through the air and result in serious bodily injury or property damage, includ- ing damage to the pump, connecting rod or bearing housing.

3.Screw the pump further into the drive housing (55) un- til it stops at the locknut (112). Unscrew the pump just until the nipple (10) faces straight back.

4.Torque the locknut (112) to 70 ft±lb (95 N.m).

5.Reassemble the remaining parts, in the reverse order of removal.

Disassembly. See Fig 19±1, except where noted.

1.

Remove and disassemble the intake valve (222). If no

 

further service is needed, reassemble the valve, us-

 

ing a new gasket (206*). Torque the intake valve to

 

80 ft±lb (107 N.m). See Fig 18±1.

2.

Remove the packing nut (221) and plug (201).

3.

Tap the piston rod (223) down with a plastic mallet.

 

Pull the rod out the bottom of the cylinder (216).

4.

Remove the packings and glands from the throat of

 

the cylinder (216).

223

112

52

10

TORQUE TO

70 ft±lb

58

(95 N.m)

 

38

INTAKE VALVE DETAIL

215 207*

*204

*206

222

TORQUE TO

80ft±lb

(107 N.m)

5. Clamp the flats of the piston rod (223) in a vise. Un-

screw the retaining nut (214). Unscrew the piston

valve (224) from the rod. Remove all parts from the

piston.

Reassembly Notes

A.

Packing Repair Kit 222±587 is available. Parts in-

 

cluded in the kit are marked with an asterisk (*) in the

 

text and drawings.

B.

Clean all parts thoroughly. Check the outside of the

 

piston rod (223) and the inside of the cylinder (216) for

Fig 18±1

0678

Reinstalling the Pump. See Fig 18±1.

1.Rotate the crankshaft (A) so the connecting rod (54) is in its lowest position. The pump piston rod (223) should protrude about 1 in. (25 mm) above the pump cylinder.

2.Screw the pump into the drive housing (55) until the pin holes are aligned with the pump coupling (36). In- sert the pin (34). Position the spring (33) so it covers the ends of the pin.

18307-724

scoring or scratches, which prevent the packings

from sealing properly. Replace all worn parts.

C. Alternate polyethylene and leather packings as

shown in Fig 19±1, starting with the polyethylene

packings. Incorrect installation damages the pack-

ings and results in pump leakage. Notice that:

the lips of the throat v±packings face down; the lips of the piston V±packings face up; the lips of the U±cup seal (205) face down.

D.Coat the piston rod and the inside of the cylinder with lightweight oil, and soak the packings in oil before reassembling.

Page 18
Image 18
Graco Inc EM390 Displacement Pump, Removing the Pump. See ±1, Reassembly Notes, Reinstalling the Pump. See ±1