Specifications and Installation
1-5
b
The exit water temperature should not exceed 120°F.
c
The outlet or discharge (nearest the foreline) should be connected to an open drain.
d
If the diffusion pump is being cooled by a recirculating water system, the system must be
capable of adequate cooling and heat exchange to ensure a continuous inlet temperature
of 60 to 80°F. The recirculating system must also be capable of maintaining an adequate
flow rate to ensure that exit water temperature does not exceed 120°F. The minimum rating
of this system should be 85 percent of the maximum power rating of the diffusion pump.
e
The quick cool coil feed line, located at the boiler plate, shoud be controlled by a separate
three-way valve (open, closed, and vent to atmosphere).
f
The quick cool drain must be connected to an open drain which is below the inlet connection
of the quick cool coil. This will ensure that the quick cool coil is completely drained when the
cooling water supply is turned off and the pump is vented to atmosphere.
1-2-5 Electrical Connections
a
The diffusion pump has been designed to operate at a specific voltage. The voltage is
specified on the label that is mounted on the side of the pump. Verify the heater rating by
measuring the resistance of the heater circuit (line-to-line) and comparing it to the values in
Tables 1-1 and 1-2, Specifications.
b
Make the electrical connections in the junction box located near the foreline. The electrical
supply should not be more than 5 percent above the rated voltage.
c
All electrical connections should be made in accordance with all applicable State, local,
and/or industrial codes.
1-2-6 Thermal Switch
a
The pump has been fitted with a manually-resettable thermal switch that is preset at the
factory. This switch is located in a box near the bottom of the pump and provides protection to
the pump in the event of excessive fluid loss, the loss of cooling water, or high inlet pressure.
WARNING
Diffusion pump heaters operate at voltages high enough to kill through
electrical shock. During installation, check the drawings and be sure to
attach all hazard warnings and cautions. Always break the primary cir-
cuit of the power supply when direct access to the heater or wiring is
required.
Read the safety section in the front of this manual.
WARNING
Failure to properly connect the thermal switch circuit in the following
step could result in catastrophic damage to personnel, the pump, or the
vacuum system.
