Southworth Products
PUN Manual
18
• Follow steps in Maintenance section to make the machine safe to inspect and
maintain.
To avoid death or serious injury:
• All maintenance and repair shall be performed with the bucket in the fully
lowered position.
• Ensure pressure has been released from the hydraulic system before
performing any maintenance. Pressurized fluid can penetrate skin and cause
death or severe injury.
Symptom
Possible Cause
Remedy
Neither lift mechanism is working: CAUTION!
If the tilt function does not begin right away,
don’t continue to operate the “up” control for
more than 2 or 3 seconds. You may damage
the pump.
The power for the unit may be switched
off.
Turn on the “Main Disconnect” switch.
One of the fuses or circuit breakers may
have opened.
Replace the fuse, or reset the circuit breaker. If
the condition repeats, determine the cause of the
problem.
The Emergency Stop switch may have
been pressed.
Reset the Emergency Stop switch, and reset the
control system.
One of the protective light beams at the
front of the unit may be blocked.
Be sure the space in front of the unit is clear.
There may be a problem with one of the
photo eyes.
Check the alignment of each photo eye and its reflec
-
tor. When the eye can “see” the reflector, the LED on
the photo eye should light. Check the power supply to
the photo eye. Replace the part if it is faulty.
The motor for the pump may have
stopped. The motor controls have built-in
over current protection in case of an
overload.
The protective circuit will reset after it has cooled.
Look for anything which may be preventing the motor
from turning.
The motor may be running backwards.
If this is happening, the pressure valve will indicate
zero pressure even though the motor is running.
Reverse any two electrical leads on the motor.
The motor may be “single phasing”.
This causes the motor to hum, but not turn. Check for
a break in one lead to the three-phase motor. Check
the motor wiring and line fuses.
The motor may be running backwards.
If this is happening, the pressure valve will indicate
zero pressure even though the motor is running.
Reverse any two electrical leads on the motor.
The motor may be “single phasing”
This causes the motor to hum, but not turn. Check for
a break in one lead to the three-phase motor. Check
the wiring and line fuses.
The voltage to the motor may be too low. Check the voltage at the starter when the motor is
under load. The supply voltage should be
10% of the rating.
The level of the hydraulic oil may be low.
When the unit is lowered completely, check the oil
level by viewing the reservoir sight gauge.
The filler/breather cap on the hydraulic
tank may be plugged.
Remove the cap and clean the baffles inside it.
There may be a vacuum leak in the suc-
tion line. (This could cause cavitation and
loss of suction in the pump.)
Check the suction line hose and fittings. CAUTION!
Do not allow cavitation to continue -- this may dam-
age the pump.
The coupling between the pump and mo-
tor may be missing.
Remove the pump as described in this section.
Check to see that the coupling is in place.
