Graco Inc 307-638, 218-026, PRO4000 manual Fan Air Valve Replacement

SERVICE

Fan Air Valve Replacement

1.Place a wrench on the flats of the valve housing (33) and remove it from the handle (2). See Fig 20.

2.Remove the retaining ring (31).

3.Rotate the air adjusting screw (34) counterclockwise until it is disengaged from the valve housing threads. Pull the adjusting screw (34) out of the valve hous- ing (33).

4.Clean all the parts and inspect them for wear or dam- age. If replacing the seal (40), unscrew it clockwise and remove it from the adjusting screw.

5.Apply medium grade thread sealant to the small threads on the end of the adjusting screw (34) and install a new seal (left hand thread).

6.When reassembling the fan air valve, lubricate the o± ring (32) and the adjusting screw threads with petro- leum jelly.

7.After the retaining ring (31) is installed on the adjust- ing screw (34), back the adjusting screw out of the valve housing (33) until it bottoms out against the re- taining ring (31).

8.Apply PTFErpaste to the threads of the valve hous- ing (33) and install it in the handle (2). Torque the housing (33) to 1.1±1.4 NSm (10±12 in±lb).

Air Valve Replacement

1.Using a screwdriver, remove the retainer (27), spring (26), and air valve (25). See Fig 21.

CAUTION

Clean all parts in non±conductive solvent compat- ible with the fluid being used, such as xylol or min- eral spirits. Use of conductive solvents can cause the gun to malfunction.

2.Remove the trigger by removing the screws and the spacers from the gun.

3.Unscrew and remove the guide (24) and packing (47) from the front of the gun handle (2).

4.Apply PTFE tape to the threads of the guide (24). In- stall the new packing (47) and guide (24) in the front of the gun handle (2). Tighten the guide (24) finger tight only.

5.Install the new air valve (25) and spring (26) into the back of the gun handle (2).

6.Apply PTFE tape to the threads of the retainer (27). Install the retainer (27) in the back of the gun handle

(2) and tighten with a screwdriver.

7.Reinstall the trigger with the screws and spacers.

8.Squeeze the trigger and tighten the guide (24) just until the valve (25) will not return when the trigger is released. Then loosen the guide just enough so the valve stem returns freely when the gun is triggered and released.

KEY			KEY			Apply
2	Gun Handle	2	2	Gun Handle
						PTFE
31	Retaining Ring		24	Guide
						tape
32	O-Ring		25	Air Valve Assembly	2
						27
33	Valve Housing		26	Spring
34	Adjusting Screw		27	Retainer
40	Valve Seal		47	Packing
		40
		31
			32
			34			26
						25

33

Torque to 1.1±1.4 NSm (10±12 in±lb)

24	47
Apply
PTFE
tape

Fig 20 Fig 21

￿4 ￿￿7￿6￿8