Unloader
Remove the locknut (67). adjusting nut (68)and spring washers (71).
Remove bolts (511 andseparatetheupper andlower casings (48 and 49). All other parts can then be freely removed.
To replace the cup and
a. Cut throughtheoldcup and
b.Grip the shaft sleeve (69) in a vise equipped with jaw protectors.
c.Slowly heat the end of the valve stem andpiston 165) with a propanetorch. Whenthe assembly ishot enough, (about 250" F [120" C]) thepistoncanbe easily screwed off the valve stem by firmly gripping with a pair of pliers.
d.After the assembly cools, mount a new
e.Beforereplacing the piston, put a few dropsof locking compound on the valve stem threads.
Items 69 and 70 are supplied as a unit and should notbe disassembled.
Assemble in reverse order withthefollowing pre- cautions:
a. Be certain the
as shown. See Fig 4.
Never shim or alter the 17 spring washers 171) as thiswill cause theunitto overpressurize and
' damaaeI Citself.A U T ' O N 1
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To readjust the pressure of the unloader valve:
a. Replace the 1/4 in. pipeplug (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 tooperation instructions on page 2.
d. The unit should"unload" at 1050 to 1150 psi (72- 79 bar)water pressure.Close the sprayvalveand note pressure. Continueadjusting the nut,closing the spray valve, and checking pressure until required pressure is obtained. Tighten the locknut.Check the unloading pressure a couple more timesby triggering the gun and noting pressure.
e. Shut off the unit, trigger gunto,relieve pressure, remove the gauge and replace the pipe plug.
NOTE: Increasing valve unloaderpressurebeyond
specifiedsetting willnot increase tlp pressure or flow rate.
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