Operation
4
307107P
Service
Pressure Relief Procedure
1.
Shut off the pump.
2.
Open the dispensing valve, if used.
3.
Open the fluid drain valve to relieve all fluid pres-
sure, having a container ready to catch the drain-
age.
Service Procedure
NOTE:
Regular cleaning and inspection of the valve,
based upon the degree and kind of service, is essential.
1.
Shut off the pump and open the back pressure valve
by turning the adjusting screw (13)
counterclock-
wise
until no spring pressure is felt. Relieve all air
and fluid pressures in the system.
2.
Remove the back pressure valve from the fluid line.
3.
Disassemble the valve and clean it with a suitable
solvent. See the parts drawing, page 5.
4.
Carefully inspect the diaphragm (12) for cracks or
other damage. Replace if necessary.
5.
Check for chips or dirt that could puncture the mem-
brane or diaphragm before assembling the valve.
6.
Check if the gasket (17) needs to be replaced.
7.
Lubricate the threads of the diaphragm retainer
(11).
8.
Install the diaphragm parts onto the valve housing
(15). Torque the retaining nut (20) to 10 to 12 ft-lb
(13.5 to 16 N-m).
9.
Carefully inspect the seat (10) for damage, wear, or
dirt. These things could cause the regulated pres-
sure to creep. Replace the seat if necessary.
10. Replace the seat gasket (14) when replacing the
seat (10). Torque the seat to 15 to 20 ft-lb (21 to 27
N-m).
11. To remove or install the gauge (8), use the wrench
on the square portion of the gauge stud only.
12. Lubricate both sides of the spring plate (7) and
spring (5) with lithium-base grease.
13. Lubricate the adjusting screw threads.
14. Assemble the remaining parts.
15. Tighten the regulator cap screws (1) finger-tight,
then torque them to 120 to 130 in-lb (13.6 to 14.7
N-m) in a criss-cross pattern. See the TOP VIEW in
the parts drawing.
16. Install the back pressure valve back in the fluid line.
PRESSURIZED EQUIPMENT HAZARD
The system pressure must be manually relieved to
prevent the system from starting or spraying
accidentally. To reduce the risk of an injury from
accidental spray from the gun, splashing fluid, or
moving parts, follow the
Pressure Relief Procedure
whenever you
• Are instructed to relieve the pressure
• Stop spraying
• Check or service any of the system equipment
• Install or clean the spray nozzle
WARNING
NOTICE
Use thread sealer sparely on the gauge’s male
threads when installing it to avoid plugging the gauge.
