MTS Series 252 Servovalves - Manual (Page 39)

Troubleshooting Guide
Series 252 Servovalve Product Information Maintenance 39
Troubleshooting Guide
The table below provides the symptom, probable cause, and remedy for some
common servovalve malfunctions that may be encountered.
Before diagnosing a servovalve malfunction, ensure that:
• The servovalve is getting the proper command.
• The servovalve is getting full system pressure and flow.
• The hydraulic fluid in the system is clean.
S YMPTOM P ROBABLE C AUSE R EMEDY
Output flow from only one
control port
Actuator is fully
extended/retracted, or
hydraulic motor is
rapidly rotating
Does not respond to the
command signal
Plugged inlet filter element Replace filter element (252.3x
only)*
Poor response (the servovalve
output lags command signal) Partially plugged filter element Clean inlet orifices or clean/replace
filter element
(252.3x only);* check for dirty
hydraulic fluid
High null bias
(a large valve balance
adjustment at the controller is
needed to maintain hydraulic
actuator in stationary position) Incorrect (mechanical or
electrical) null adjustment
Partially plugged inlet orifice
assembly
Partially plugged filter element
Adjust null
Clean inlet orifices
Clean/replace filter element (252.3X
only);* check for dirty hydraulic
fluid
* For a Series 252.2X or 252.4X Servovalve, return the unit to MTS.