Enerpac HPT-Series User Manual

Page 3

5.0 OPERATION

1. Release handle lock pin located under beam.

2. The pump may be operated as a vented or a non-vented

pump. Turn the reservoir vent/fi

ll cap to the desired

position.

WARNING: Do not stand directly over the pump handle.

It is possible for the pump handle to “kick back.” Keep
your body to the side of the pump and away from the

line of force of the handle.

3. Open pump release valve by turning knob counterclockwise

one turn. Operate the pump using full strokes six or more
times as necessary to purge air from the pump circuit.

4. Open

reservoir

vent/fi ll cap and check the oil level. Fill the

reservoir (using Enerpac oil only) to the indicator mark on the
end cap. DO NOT overfi ll.

NOTE: The HPN and HPT Series pumps have a usable oil capacity
of 155 cu. in [2540 cm

5. Close release valve by turning knob clockwise.

NOTE: Release valve is designed to close with hand pressure
only. Use of tools to close valve can result in damage to the valve
and/or valve seat.

6. The pump may be operated from either the horizontal or

vertical position. If operated in the vertical position, the
discharge port must be down.

7. The

HPN and HPT Series pumps are two-stage pumps. The

shift from fi rst to second stage is automatic when the system
pressure reaches approximately 200 psi [13.8 bar]. To reduce
handle effort at high pressure, take short strokes.

NOTE: Allow for oil compressibility when designing a system. In
low pressure applications oil compressibility will be negligible, but
as pressure increases, oil will compress at a rate of approximately
1/2

per 1000 psi [68.9 bar].

5.1 Relief Valve Adjustment

All HPN and HPT Series pumps contain a factory set internal
relief valve to help prevent overpressurization of the system. This
valve is not user-adjustable.

WARNING: Do not attempt to readjust or disable the

internal relief valve. Serious personal injury and/or
equipment damage could result.

5.2 Air Removal

Remove trapped air from the circuit as described in the following
steps:

1. Move the reservoir vent/fi ll cap to the “vent” position.

2. Close the pump release valve by turning knob clockwise.

3. Position the pump at a higher elevation than the hydraulic

nut or tensioner. Be sure that the piston end is DOWN.

4. Operate pump to fully extend the hydraulic tensioner or

hydraulic nut. Be careful to ensure that the maximum stroke
for the nut or tensioner is not exceeded.

5. Open the release valve to retract the hydraulic nut or

tensioner. If necessary, apply some force to assist the
retracting process. This will force the trapped air to move up
into the pump reservoir.

6. Repeat step 5 as necessary to remove all the trapped air

from the circuit.

7. Remove

the

vent/fi ll cap. Add additional oil to the reservoir,

if necessary.

8. Reinstall

the

vent/fi ll cap. Be sure to return the cap to the

“vent” position.

6.0 MAINTENANCE

To check pump oil level:

1. Open the release valve to allow oil in the system to return to

the reservoir.

2. Remove the reservoir vent/fi ll cap.

3. Add Enerpac hydraulic oil until oil level is up to the indicator

mark on the pump end cap. Do not overfi ll.

4. Reinstall

the

vent/fi ll cap. Return the cap to the “vent”

position.

• To function, all hand pumps require some air in the reservoir. If
the oil level is too high, the pump will not operate properly.

• If the pump is operated under dirty conditions, more frequent
oil changes are recommended. Refi ll with clean Enerpac oil.

• Periodically lubricate the beam pin, cross pin, and piston
head.

Figure 2, Pump Features and Components

Key:

1 - Coupling
2 - Pressure Gauge
3 - Release Valve Knob
4 - Handle Lock Pin
5 - Handle
6 - Vent/Fill Cap