General Pump ZH284KEZ User manual
ZH284KEZ
FLOW SENSITIVE FLOW SENSITIVE
• Suitable for Industrial use
• Dual bypass port
• Extremely reliable
• Easy maintenance
GENERAL PUMP A member of the Interpump Group
FEATURES
PARTS LIST
SPECIFICATIONS
Trapped Pressure Unloader Valve
General Pump
recommends using a
safety relief device in
conjunction with
this unloader valve
when installed on a
positive displacement
pump. General Pump is
not liable and assumes
no responsibility when
used in a customer’s
high pressure system.
Ref 301085 Rev. B
02-22
Part Number ZH284KEZ
Max Volume 10.5 GPM
Max Operating Pressure 4,060 PSI
Max Temperature 194° F
Port Sizes Inlet: (2) 3/8” NPT-F
Outlet: 3/8” NPT-F
Bypass: 3/8” NPT-F
Dimensions 7.24” x 3.31” x 2.05”
Weight 2.22 lbs
General Pump
is a member of
the Interpump Group
No. Part No. Description Qty.
1 36359741 Housing 1
2* 90358500 O-ring, Ø 10.82 x 1.78 1
3* 36326566 Seat 1
4* 97483800 Ball, 13/32" (10.319 mm) 2
6* 90359100 O-ring, Ø 14 x 1.78 1
7* 36310451 Valve Guide 1
8* 90382300 O-ring, Ø 9.92 x 2.62 1
9 36359070 Outlet Nipple 1
10* 90359300 O-ring, Ø 15.6 x 1.78 1
11 36359573 Piston Rod 1
12* 90006300 Anti-Extrusion Ring, D.8 - DF. 1.2 1
13 36326466 Piston Guide 1
14* 90507000 Anti-Extrusion Ring, Ø 11.6 x 16 x 1.5/2 1
15* 90382500 O-ring, Ø 10.78 x 2.62 1
16* 90357600 O-ring, Ø 6.75 x 1.78 1
17 36335770 Spacer 1
18 36335670 Piston Rod Bushing 1
19* 90503600 Anti-Extrusion Ring, Ø 8 x 12.4 x 2.5/3 1
20* 90381800 O-ring, Ø 7.59 x 2.62 1
21* 90359500 O-ring, Ø17.17 x 1.78 1
22 97665800 Plug, Ø 3 x 12 1
23 36358970 Nut, M08 x 4.5 2
24 36352670 Pressure Register 1
25 36352700 Spring Holder Ring 1
26 872011054 Nut, M8 1
27 36326051 Knob 1
28 36329751 Yoke 1
29 98209430 Plug, 3/8" NPT x 12.7 1
32* 94750700 Spring, Ø 21 x 53 1
33 94735500 Spring, Ø 8.5 x 12 1
35 36359470 Inlet Plug 1
* K421 Repair Kit
No. Torque Specs
9 13.49 ft. lbs / 60 Nm
18 11.24 . lbs / 50 Nm
29 9 ft. lbs./ 40 Nm
35 6.74 ft. lbs. / 30 Nm
ZH284KEZ
GENERAL PUMP A member of the Interpump Group
Trapped Pressure Unloader Valve
DIMENSIONS
THIS DOCUMENT PROVIDES THE INSTRUCTIONS FOR THE INSTALLATION, USE AND MAINTENANCE OF THE VALVE, THEREFORE IT IS
AN INTEGRAL PART OF THE VALVE ITSELF AND MUST BE READ CAREFULLY BEFORE ANY USE AND KEPT WITH CARE.
STRICTLY COMPLY WITH THE INSTRUCTIONS CONTAINED IN THIS DOCUMENT IN VIEW OF A SAFE AND EFFECTIVE USE OF THE VALVE.
FAILURE TO COMPLY WITH THESE INSTRUCTIONS MIGHT CAUSE EARLY FAULTS AND RESULT IN SITUATIONS OF DANGER, IN
ADDITION TO VOIDING ANY WARRANTY.
1-GENERAL INFORMATION:
1.1- The ZH284KEZ automatic pressure regulator is a manually-adjustable, pressure-operated device which, according to its setting, limits the pump/
system pressure by conveying the excess of water to the by-pass. Moreover, when the outlet flow is blocked, this device totally releases the flow - and
keeps under pressure the portion of the system following the valve, while it sets the pressure to zero in the portion of the system preceding the valve.
2-WARNINGS:
2.1- To ensure the tightness of the fittings used to connect the valve to the system, interpose a metal washer with a rubber ring or insert an appropri-
ate sealing on the thread and tighten them.
2.2- Use guns or other control devices ensuring a perfect seal when closed. Leakages may compromise the correct functioning of the valve.
2.3 - WARNING: The nut pos. 23 is a mechanical security stop that limits the maximum pressure. Do not remove for any reason.
3-INSTRUCTIONS FOR CALIBRATION:
The valve is calibrated to the maximum pressure value shown in the table, IT IS NOT ALLOWED TO EXCEED THIS VALUE
3.1- Connect the valve to the water system and follow these steps:
3.2- Unloose the adjustment knob pos.27 in order to completely release the spring.
3.3- Open the gun or the water control device and start the system. Make sure that the air contained in it is fully ejected.
3.4- Keeping the gun or the water control device open, start adjusting the pressure by screwing down the knob pos.27. Alternate the adjusting oper-
ations with a few openings and closings of the gun or of the control device. When the desired pressure has been reached, open and close the gun/
control device a few times again in order to stabilize the various components (seals, springs etc.). Check the pressure value again and correct if nec-
essary.
In case of doubts, do not hesitate to contact the General Pump Customer Service.
IMPORTANT: During use, never exceed the maximum values of pressure, flow-rate and temperature as stated in this document and/
or indicated on the valve.
INSTALLATION AND INSTRUCTIONS FOR USE
Ref 301085 Rev. B
02-22
Ref 301085 Rev. B
02-22
PROBLEMS PROBABLE CAUSES SOLUTIONS
Frequent valve recycles • Damaged check valve O-ring
• Leaking connections
• Restricted bypass or too small diameter of
the bypass hose
• Replace
• Check or renew
• Clean or adapt passage diameter
Valve does not reach
pressure
• Piston O-rings worn out
• Debris between seat and shutter
• Seat worn out
• Nozzle worn out
• Incorrect choice of nozzle
• Replace
• Clean the seat
• Replace
• Replace
• Fit with smaller nozzle
High pressure peaks at
gun closure
• There is not a minimum of 5% of total flow
discharged in bypass
• Excessive flow in bypass
• Adjustment with spring totally compressed
• Reset Correctly
• Change type of valve or adjust
passages
• Loosen adjustment screw and
eventually fit with smaller nozzle
Valve does not discharge
at low pressure at gun
closure
• Jammed check valve
• Debris on check valve
• Clean or replace
• Clean
TROUBLESHOOTING
GENERAL PUMP 1174 Northland Drive • Mendota Heights, MN 55120
ZH284KEZ
GENERAL PUMP A member of the Interpump Group
Trapped Pressure Unloader Valve
MAINTENANCE
STANDARD: every 400 working hours, check and lubricate the seals with water resistant grease.
SPECIAL: every 800 working hours, check the wear of the seals and internal parts and, if necessary, replace with
original GP parts taking care, during installation, to lubricate with water resistant grease.
The manufacturer is not to be considered responsible for damage as a result from incorrect fitting and
maintenance.
WARNING: This product can expose you to chemicals including
lead, which is know to the state of California to cause cancer and
birth defects or other reproductive harm. For more information, go
to www.P65Warnings.ca.gov
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