77
Service Instructions
MAN-02-08-77-0714-EN Rev. 2
September 2020
Section 9: Troubleshooting
Troubleshooting
Section 9: Troubleshooting
!
WARNING
To prevent personal injury, the actuator must be in double-acting, Fail-safe Position and all
hydraulic pressure drained, including an optional accumulator, before opening any tube
lines or attempting replacement operations below.
Of all the system components, the actuator itself is least likely to malfunction and require
the most time and effort to service.
Table 30.
Troubleshooting
Symptoms
Possible Reason
EHO does not turn on
1. Ensure voltage is adequate to the unit.
2. Check to see that the electrical power is connected to the
correct terminals.
3. Branch circuit fuse blown out.
EHO is on, but motor does not run
1. Ensure the Local/Off/Auto switch is in the proper position.
2. Ensure the field power wiring is an adequate size.
3. Power supply is insufficient.
4. Check to see if thermal overload is tripped.
EHO motor runs, but fails to
develop sufficient pressure to
open the valve
1. Low fluid level in reservoir.
2. Wrong motor shaft rotation.
3. Hand pump isolation valve (O) is closed
(if optional accumulator is provided).
4. ESD solenoid is not energized because signal power
is insufficient.
5. The Relief valve is cracking open.
Check to ensure setting set to factory setting.
ESD solenoid (optional)
1. Ensure the Local/Off/Auto switch is in the proper position
when initiating the open/close command.
2. Hand pump isolation valve (O) is closed; preventing
ability to stroke to the Fail-safe Position.
Should any issue be experienced besides the symptoms noted above, please consult factory.
Important check points for automatic operation of the EHO:
1.
Ensure oil level is at the proper level.
2.
Ensure hand pump isolation valve (O) is open.
3.
Check to see that the ESD (optional) signal power is on.