PA VB 16 User manual

Last update: 20/04/18
1
VB 16-UnloaderValve (discharging)
Technicalmanual: E 234
Pressure regulating unloader valve with discharge control pressure with very low readings.
At gun-lance closure, the water flow is bypassed at reduced pressure DN 15
Technical specifications
Max. flow rate: 80 l/min. Max temperature: 90°C (1)
Part number
Rated
pressure
bar - MPa
Permissible
pressure
bar - MPa
Minimum
adjustable
pressure
bar - MPa
Pressure remainder
at circuit closure
bar
300 400 500
MPa
(30) (40) (50)
(2) Pressure drop
to reset bypass
bar
300 400 500
MPa
(30) (40) (50)
Inlet
outlet
bypass
Weight
g
60.8000.00
500 -50
560 -56
100 - 10
140
(14)
165
(16.5)
190
(19)
65
(6.5)
90
(9)
110
(11)
G1/2 FF
3450
(1) The valve has been designed for a continuous use at a water temperature of 60°C. It can resist for short periods at a
maximum temperature of 90°C.
(2) This is the pressure reduction necessary in comparison to the set up, in order that the valve brings back pressure in
the circuit.
Instruction manual, maintenance, installation, spare parts.
For a correct utilization, follow the directions of this manual
Re-print them on the Use and Maintenance booklet of the machine.
n. 12.9234.00
60.8000.00 VB 16 G1/2 FF
- Sturdy steel and brass construction.
- By-pass control actuated at very low pressure values with
reduced pressure in the delivery line when gun is shut.
-Quick start at gun opening assures gradual pressure reset,
essential for use on endothermic engines.
-Specially designed check valve prevents jamming and vibrations
even in presence of sand and scales
-Working typology protected by registered patent.

Last update: 20/04/18
2
DIMENSIONAL DRAWING
INSTRUCTIONS
SELECTION
This product is to be utilized with clean fresh water, even slightly additivated with normal detergents. For use involving different or
corrosive liquids, contact the PA Technical department. Appropriate filtration should be installed when using unclean liquids. Choose
the valve in line with the data of nominal running (system rated pressure, max flow and max temperature). In any case, the pressure of
the machine should not exceed the permissible pressure rate imprimed on the valve.
INSTALLATION
This accessory, on a system that produces hot water, must be fitted upstream the heat generator. This product is bound to be
incorporated on a finished machine. On a system that generates hot water, anticipate the fitting of accessories that limit the accidental
increase of fluid temperature.
Always install a safety valve that protects the pressurized inlet channel.
Choose a correct nozzle size, which allows a regular discharge on bypass, at least 5% of the total flow of the system in order to
achieve a constant pressure value and avoid troublesome pressure spikes at closure. If the nozzle wears out, the pressure drops.
On installation of a new nozzle, re-adjust the system to the original pressure setting.
OPERATIONS
The valve regulates the the max pressure of the system through a piston, which acts on a ball correctly positioned, that closes the
bypass opening. A check valve cuts out the delivery section, the pressure of which controls the drive of the piston.
Each regulation should be made when the system is operational and the nozzle open.
ATTENTION: In order not to overstep the max pressure, the nut (pos 36) must be fastened and never removed otherwise a
mechanical safety feature would lack that limits the max pressure avoiding serious damage to persons and machine.
Mark the position with a drop of paint in order to prevent possible slackening and tampering.
The balanced conformation of the valve allows a renewed pressure at very low readings giving a longer function in bypass and a
progressive restart, without unpleasant pressure spikes, useful with endothermic engines.
DISCHARGE SYSTEM AND WATER ADDUCTION
The bypass line should be returned into a tank with deflectors. By using a direct pump recycle, with elevated pressure intake, it is
necessary to install a pressure reducer in order to have an even flow supply and to protect the circuit intake.
When long bypass conditions occur, direct to the pump intake, it is advisable to fit a thermal protector valve (VT3 or VT6) in order to
eliminate excessive temperature build up.

Last update: 20/04/18
3
SYSTEM (Technical notes)
Due to the high pressure and flow valves used, always install an adequate pressure dampener in order to balance delivery flows.
Connection between pump and valve must be made through a flexible hose, at least 1,5m. long, in order to avoid transmission of
vibrations to the valve, especially when using endothermic engines. Valve must be properly installed by using the threaded holes on the
valve body.
PROBLEMS AND SOLUTIONS
PROBLEMS
PROBABLE CAUSES
SOLUTIONS
Frequent unloader recycles
Damaged seat or cone
Leaking connections
Restricted bypass
Replace
Check and renew
Clean or adapt
Unloader does not reach
pressure
Unloader not properly sized
Piston O rings worn out
Material matter between seat and shutter
Worn out nozzle
Damaged safety valve
Change spring or type of valve
Replace
Clean the seat
Replace
Replace
Pressure peaks
There is not a min of 5% of total flow in bypass
Excessive flow in bypass
Spring totally compressed
Reset
Change type of valve or adjust passages
Loosen knob and change nozzle
Unloader does not bypass at
low pressure
Jammed check valve
Check valve O ring worn out
Material matter on check valve
Clean or replace
Replace
Clean
REGULATIONS : see norm manual
For a correct utilization, follow the directions described in this manual and re-print them on the Use and maintenace manual of the
machine.
Make sure that you are given the Original Conformity Declaration for the accessory chosen. The present manual is valid for all
unloader valves named VB 16.
MAINTENANCE
Maintenance has to be carried out by Specialized Technicians.
STANDARD: every 400 working hours (circa 10,000 cycles), check and lubricate the seals with water resistant grease.
SPECIAL: every 800 working hours( circa 20,000 cycles), control the wear of the seals and internal parts and if necessary, replace with
original PA parts taking care during installation and to lubricate with water resistant grease.
ATTENTION: reassemble the valve in the correct manner paying special attention to the Nut (pos 31) which must
always be in place.
The manufacturer is not to be considered responsible for damage as a result from incorrect fitting and
maintenance
Technical data, descriptions and illustrations are indicative and liable to modification without notice.

Last updated 03/07/2019
60.8000.00 VB16 unload. 1/2F Bsp
Pos. P/N Description Q.ty K1K2K3K4 Pos. P/N Description Q.ty K1K2K3K4
1 60.8003.31 Plug, M38x1 brass 1 3
2 10.4089.00 Back-up ring, 32,7x35,5x1,5 mm 1 • 5
3 10.3078.08 O-ring, 1,78x31,45 mm Ni 85 1 • 10
4 10.3058.02 O-ring, 1,78x10,82 mm Ni 85 1 • 10
5 10.4090.00 Back-up ring, 11,2x14x1,5 mm 1 • 10
6 10.3077.28 O-ring, 1,78x29,87 mm Ni 85 1 • 10
7 10.4088.00 Back-up ring, 31,2x34x1,5 mm 1 • 5
8 60.8012.51 Spacer ring, 14,5x34x27,5 mm Sst. 1 3
9 60.8016.31 Spacer ring, 5,2x19x12,5 mm brass 1 3
10 60.8022.51 Piston, 5x43,8 mm Sst. 1 3
11 60.8004.51 Spring, 3,5x17,5x29 mm Sst. 1 3
12 60.8013.31 Seat holding spacer, brass 1 3
13 60.8015.51 Seat, 3x14x7,5 mm Sst. 1 • 5
14 14.7418.71 Ball, 5/32" 1 • 5
15 60.8014.51 Ball holding piston, Sst. 1 5
16 60.8006.51 Spring, 1x7,2x14 mm Sst. 1 3
17 11.4574.11 Hex. nut, M8, Sst. 1 10
18 60.8023.24 Seat, 14mm Sst. + shutter pin, Sst. 1 • 1
19 10.4085.00 Back-up ring, 29,2x32 mm 1 • 5
20 10.3077.08 O-ring, 1,78x28,3 mm Ni 85 1 • 10
21 60.8011.31 Spacer ring, 1 3
22 60.8002.51 Piston, M8-M10 Sst. 1 3
23 10.4086.00 Back-up ring, 6,3x8,5x1,5 mm 1 • 5
24 10.3018.08 O-ring, 1,5x6 mm Ni 85 1 • 10
25 10.4094.00 Back-up ring, 15,5x20x5 mm 2 • 5
26 10.3180.08 O-ring, 2,62x15,08 mm Ni 85 1 • 10
27 10.4087.00 Back-up ring, 23,5x26,5x2,5 mm 1 • 5
28 10.3073.08 O-ring, 1,78x23,52 mm Ni 85 1 • 10
29 60.8010.51 Spacer ring, 12,2x26,5x33,5 mm Sst. 1 3
30 10.2012.00 Stem seal, 12x19x2,8 mm +O-ring 1 • 5
31 60.8001.35 Housing -VB16, 1/2F Bsp brass 1 1
32 60.0022.31 Grub screw, brass 1/4 Bsp 1 5
33 11.6500.09 Plate, 10,9x1,5 mm Cu 1 5
34 60.8005.61 Spring, 7x42,5x48 mm z.pl. 1 3
35 60.8017.31 Spring guiding washer, brass 1 3
36 60.8018.61 Valve regulating nut, M10 z.pl. 1 3
37 15.1042.00 Roll pin, 3x26 mm Sst. 1 10
38 10.4091.00 Back-up ring, 21,2x24x1,5 mm 1 • 5
39 10.3072.01 O-ring, 1,78x20,35 mm Ni 85 1 • 10
40 60.8019.51 Shutter seat, Sst. 1 3
41 10.3292.08 O-ring, 4x8 mm Ni 85 1 • 10
42 60.8020.51 Pin, hex.17 Sst 1 3
43 60.8007.51 Spring, 0,8x12,2x27 mm Sst. 1 3
44 10.3072.60 O-ring, 1,78x21,95 mm Ni 85 1 • 10
45 10.4092.00 Back-up ring, 22,7x25,5x1,5 mm 1 • 5
46 60.8021.31 Shutter coupl., 1/2F Bsp brass 1 3
Kit P/N Description
K1 60.8025.24 Spares kit -VB16, 24x1pcs. 1