SERVICING
CAUTION: Before commencing with service, shut off drive (electric
motor, gas or diesel engine) and turn off water supply to pump.
Relieve all discharge line pressure by triggering gun or opening valve
in discharge line.
Disassembly
1. Disconnect by-pass, discharge and inlet plumbing from regulator.
2. Remove regulator from pump.
3. Secure lower body of regulator in a vise with brass adjusting nut
facing up.
4. Remove upper body by unthreading from lower body.
5. Grasp top of piston stem and separate from conical piston.
6. Remove piston stem with stack of spring washers, flat washers
and anti-rotating washer and place on flat surface.
7. Remove conical piston with reverse pliers by making contact on
the inside diameter of conical piston.
NOTICE: Exercise extreme caution to avoid contact and damage to
outside diameter and sharp tip of conical piston.
8. Remove piston retainer from lower body of regulator.
NOTICE: Exercise extreme caution to avoid contact and damage to
the inside diameter of the piston retainer.
9. Remove conical seat from lower body of regulator.
NOTICE: Exercise extreme caution to avoid contact and damage to
outside diameter and the tapered surface of the seat.
Note: With the regulator completely disassembled, inspect lower
body sealing areas where the conical seat and piston retainer makes
contact for grooves, pitting and wear. If damage is found, replace
with new lower body or complete new regulator. If not, proceed with
reassembly.
Reassembly
Note: Conical piston and seat should be changed as a matched set
when upgrading from the old tapered piston and seat. See Tech
Bulletin 097.
Note: Spring washers and flat washers should be changed as a
spring set. See Tech Bulletin 102.
1. Place lower regulator body with by-pass port facing down into a
vise.
2. Lubricate and install o-ring onto outside diameter of conical seat.
Press conical seat down into lower regulator body with small hole
facing up.
3. Lubricate and install o-ring onto piston retainer. Press piston
retainer with raised surface facing up.
4. Lubricate and install back-up-ring, then o-ring onto outside
diameter of conical piston. Press conical piston with sharp point
down into piston retainer.
5. Replace piston stem with stack of spring washers and flat washers
into hole of conical piston.
6. Place anti-rotating washer on top of spring set. Align tabs on
washer with slots on the upper body.
Note: The number of flat washers varies with each spring set. Place
the first flat washer between the anti-rotating washer and spring stack.
Place second washer (if required) between spring stack and retaining
ring. Place all remaining washers with first washer.
7. Thread upper body into lower body.
8. Re-install regulator onto pump.
9. Reconnect by-pass, discharge and inlet plumbing to regulator.
10. Proceed to PRESSURE ADJUSTMENT.
Read all CAUTIONS and WARNINGS before commencing
service or operation of any high-pressure system
TROUBLESHOOTING
Cycling /Chattering l Too little flow for valve specifications.
l Air in system, poor connections.
l Inlet seals in pump worn.
l O-ring in gun worn.
System will not l Nozzle worn.
build up to pressure l Improper nozzle size for system specs.
l Foreign material trapped in seat.
Pressure drop l Nozzles worn.
l Piston and seat in regulator worn.
l Air in system, poor connections.
l Insufficient flow to pump.
l Filter clogged. Check and clean regularly.
l Fatigued or broken spring washers.
Pressure spikes l Minimum by-pass of 5% not present.
while in by-pass l Excessive pressure adjustment made for worn
nozzle. REPLACE NOZZLE. Reset system pressure.
Leakage from l O-ring around piston worn. Service with O-ring Kit.
regulator vent hole l Piston Retainer scored. Service with O-ring kit and
or top slots replace retainer.
l Fatigued or broken spring washers.
Approximate Gauge Gauge
Pressure Reading Between Between
at Gauge Pump/Unloader Unloader/Gun-Nozzle-Valve
System in operation system pressure system pressure
(gun open)
System in by-pass 200-300 PSI above 200-300 PSI above
(gun closed) system pressure system pressure
PRESSURE READING
