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Hersteller: Graco Inc. Dateigröße: 526.21 kb Dateiname: Unterrichtssprache:

4 307-308 - Plugged or constricted Examine the water in the barrel or tank for air suction piping (suction valve bubbles while thepumpis discharging. Ifno not fully open); Collapsed suction hose. Decreased Delivery Worn valve seats. Accompanied By Smooth Operation Slipping couplers. Excessive Leakage Worn piston cups; Loose piston bolts; Damaged O-rings; Cracked ceramic liners; Faulty gaskets; Loose valve caps; Loose cylinder head bolts or malfitted heads. SERVICE Pistons and Yoke Take off the cylinder head (14) by removing four 112 in. socket head capscrews See Fig 3. (A). Use a 7/32 in. socket wrenchto unscrew the piston bolt (13) from the yoke. Slide out the cylinder liner (21) and piston assembly. Leave the yoke in place. Examine the ceramic cylinder liner (21)forcracks.tight Replace worn or cracked parts before reassemblinginto pump body. NOTE: Dirty grease sludge adhering to thewallof thecylinder liner should beremoved with emery cloth before theliner is replaced in the pump body. bubbles are seen and the discharge has actually decreased, look for plug-ups, worn valve seats, or collapsed suction hose. If bubbles are seen, look for air leaks in the suction piping or for air leaking past the piston cups. These leaks are hard to find because they are leaking "in" rather than "out". However,if are made to put arrangements pressure into thesuction piping orifnewcups smooth out the pump operation, the problem is solved Lookfor worn or pitted valve seats. Replace if necessary. eccentric roller bearing andyokepads Measureclearancebetweenoutersurface with a or feeler gauge. This should not exceed 0.010 inch (0.2% mm). NOTE: Worn yoke pads will give a verynoisy operation. Replace the yoke or pads if necessary. Examine pistons and cups for wear. Generally a cup will not leak severely until it is torn. The piston should not be more than0.020in. 10.508 mm) out of round. Tighten loose piston bolts, cylinder head bolts and valvecaps. Removeheadandsand flat part on 80-grit sandpaper which is laid on a flat surface. CheckO-rings andgaskets for wear orbreaks. Remove cylinder heads and blocks to examine ceramic liners for cracks. Replace all damaged parts. Assembleallpistonparts (10. 11. 12. 13,21, 22, 23,24) as shown and push the assembly into the. cylinder liner. Make sure that the O-ring is in the recess of the piston cap. Screw the piston bolt into the yoke. The bolt has a countersunkheadcapscrewofthelockwelltypeand will require a-little extra effort to turn. Make certain it is to prevent leakage through the b.olt hole. Repeat the procedure for the oppositeside of the pump. ' ' 307-308 5 Valve Replacement .. Mount the valve disc (61 on the spring (7). See Fig 3. Make sure that the O-rings (2 & 3)have been inserted in Then mount the spring in the cage recess (8). Slip thls the proper places accordingto the diagram. It is Wise to assembly into the head cavities behindthe valve seat (5) grease the head O-rings to prevent them from fallingOut and O-rings (4). Put the valve caps 115) over these and during assembly. install bolts (161. Bolting Cylinder Head AssemblyTo Pump Body install the cylinder (14) head right side up on the pump body, as shown. 17- '*Repair Kit Pam Fig 3 9" 6 307-308 Unloader Remove the locknut (67). adjusting nut (68)and spring washers (71). Remove bolts (511 andseparatetheupper andlower casings (48and 49). All other parts can then be freely removed. To replace the cup and back-up ring (46 and 47): a. Cut throughtheoldcup and back-up ringand remove them from the valve stem. b. Grip the shaft sleeve (69)in a vise equipped with jaw protectors. c. Slowly heat the end of the valve stem and piston 165) with a propanetorch. Whenthe assembly is hot enough, (about 250" F [120" C]) the piston can be easily screwed off the valve stem by firmly gripping with a pair of pliers. d. After the assembly cools, mount a new back-up ring and cup on the piston. e. Beforereplacing the piston, put a few drops of locking compound on the valve stem threads. Items 69and 70 are supplied as a unit and should not be disassembled. Assemble in reverse order with thefollowing pre- cautions: a. Be certain the by-pass valve seat (58)is installed with the flat side of the valve against the valve ball (60). b. The first spring washer (71) is installed concave side downward and the remaining springs are alternated as shown. See Fig 4. Never shim or alter the 17 spring washers 171) as thiswill cause theunitto overpressurize and damaae itself. 'I CAUT'ON1 ~~ ~ To readjust the pressure of the unloader valve: a. Replace the 1/4 in. pipe plug (102) in theoutlet manifold (101)with a 1500 psi (103bar) min. pressure gauge. b. Screw the adjusting nut (68)into the stem (69) until approximately 118 in. of thread is exposed. c. Start the unit according to operation instructions on page 2. d. The unit should "unload" at 1050 to 1150 psi (72- 79 bar)water pressure.Close the spray valveand note pressure. Continue adjusting the nut, closing the spray ...

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