www.energyabsorption.com
Revision B December 2013
www.highwayguardrail.com
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Relief Valves
1.
The Purpose of a Relief Valve is to:
A. Limit the maximum pressure in the system to a safe level.
B. Keep the current draw and battery drain at a minimum when the cylinder “deadheads”
(reaches full stroke).
2.
The Pump relief Valves on TMA’s are Basically the Same Except:
An internal cavity is drilled into the pump base on Monarch pumps for the relief valve.
The following parts are inserted to make up the relief valve assembly.
A. Ball or Cone
B. Heavy Spring
C. Adjusting Screw
3.
Diagnosing and Repairing Relief Valves
Note:
When testing or making adjustments on the relief valve the system must be
''deadheaded'' (cylinder at full stroke or in a position where cylinder movement is zero).
A. Relief valve pressure too high.
1. Symptoms:
a. Current draw and battery drain excessive when system is “deadheaded.”
b. Motor RPM is slow in comparison to full load system operation.
2. Repair procedure:
Turn relief valve adjusting screw counterclockwise using a pressure gauge teed
into a high-pressure line to record the proper pressure setting.
Note:
On the Monarch relief valve the jam nut will need to be loosened before adjusting.
The Monarch relief valve is adjusted with an
Allen
wrench. Re-tighten the jam nut.
B. Relief valve pressure too low.
1. Symptoms
a. Motor RPM is “faster” than normal.
b. Cylinder will not extend.
c. Excessive turbulence in the reservoir.
Recommended Pressure:
Monarch: 1800 psi [12.4 MPa]
