MTS Series 505 SilentFlo Hydraulic Power Unit Model 505-30 - Manual (Page 53)

Low/High Pressure Functionality
Model 505.20 - 505.30 SilentFlo™ HPU Operation 53
The effective range of the auto-cooling circuit is between system pressures of 14
MPa (2000 psi) to 21 MPa (3000 psi). In order for the auto-cooling valve to
function properly, it must be re-adjusted anytime the output pressure will be
changed for longer than 10 minutes.
Note If the test condition requires a maximum pressure level less than 14 MPa
(2000 psi), consult MTS.