AAON LN-140 - Manual (Page 44)

44
Discharge Valve
This valve performs the dual function of
automatically sealing the discharge of the
inactive pump when one pump is running
and can manually be closed and locked to
isolate one pump for service.
Automatic Flapper Operation
In the flapper mode the two halves of the
discharge
valve are free to pivot
independently under normal operating
conditions. The locking handle (3) should be
secured with the set screw (11) in the
vertical position with the center pin of the
locking arm (4) trapped by the locking
handle (3).
Manual Valve Locking
The locking feature of this valve is to ensure
a positive seal (leak proof) of the discharge
port on the pump to be serviced.
Note: Ensure the pump to be isolated is not
operating before attempting to release the
locking mechanism. Failure to do so may
result in injury to the operator and/or
damage to the pump.
Locking
1. Loosen discharge side set screw (11) to
release the locking handle (3).
2. Rotate the discharge side locking handle
(3) so that the handle points toward the
pump to be serviced and secure in the
horizontal position, using set screw (11).
This releases the discharge locking arm
(4).
3. Rotate discharge valve shaft (16)
towards the pump to be isolated. The
orientation of the shaft is indicated by
the center pin on the locking arm (4).
4. Raise the locking handle (3) so that the
cam on the base of the handle forces the
pin of the locking arm (4) towards the
pump to be isolated. The locking handle
(3) should be raised to between 45
degrees and the vertical position.
5. Tighten set screw (11) to lock the
locking handle (3) in position.
This handle should not be rotated past the
vertical position.
Note: Ensure the isolated pump is not
operating before attempting to release the
locking mechanism. Failure to do so may
result in injury to the operator and/or
damage the pump.
Unlocking
1. Open the interconnecting valve on the
seal flush line to pressurize the serviced
pump and vent air through bleeder valve
on series 4302
2. Close these valves once the pressure is
equalized and air removed.
3. Loosen set screw (11) and lower locking
handle (3) to the horizontal position,
secure with set screw (11).
4. Rotate valve to center position so that
the center pin of the locking arm (4)
locates in the recess on the locking
handle (3).
5. Loosen set screw (11) and raise locking
arm (3) to the vertical position, locking
the center pin in the locking arm recess,
secure with set screw (11).
Suction Valve
Manual Operation
The suction side valve is designed for use as
a manually operated isolation valve. This
valve is not designed to automatically pivot
as the discharge flappers do.
Care should be taken when
performing procedures 3 and 4. Read
instructions carefully.
WARNING