Danfoss H1 078 - Bypass Function; Charge Pressure Relief Valve

High Pressure Relief and Charge Check Valve with Bypass Valve in charging mode
P003 269
High Pressure Relief and Charge Check Valve with Bypass Valve in relief mode
P003 268
Pressures marked on HPRV valve
Mark Pressure bar [psi]
20 200 [2900]
25 250 [3626]
30 300 [4351]
35 350 [5076]
37 370 [5366]
40 400 [5801]
42 420 [6092]
45 450 [6527]
48 480 [6962]
51 510 [7397]
Bypass Function
The HPRV valve also provides a loop bypass function when each of the two HPRV hex plugs are
mechanically backed out 3 full turns. Engaging the bypass function hydraulically connects both A & B
sides of the working loop to the common charge gallery. The bypass function allows you to move a
machine or load without rotating the pump shaft or prime mover.
C
Caution
The HPRV valves are not tow valves. Damage to the pump and motor can occur when operating without
charge flow. Limit vehicle/machine movement to no more than 20% of maximum speed and no longer
that three minutes. Reseat the HPRV valves after vehicle/machine movement.
Charge Pressure Relief Valve
The charge pressure relief valve maintains charge pressure at a designated level above case pressure. The
charge pressure relief valve is a direct acting poppet valve that opens and discharges fluid to the pump
case when pressure exceeds a designated level. This level is nominally set with the pump running at 1800
Service Manual
H1 Pumps 069/078, 089/100, 115/130, 147/165, 210/250
Operation
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Danfoss | May 2018 520L0848 | AX00000087en-US0308