Instruction manual

VHS-4, VHS-6 and VHS-250 Diffusion Pumps

D R A F T 6 / 1 8 / 1 3

❑

The minimum rating of this system should be 85% of the

maximum power rating of the diffusion pump.

❑

The Quick Cool Coil feed line, located at the boiler plate,

should be controlled by a separate three-way valve (open,

closed, and vent to atmosphere).

2. Connect the quick cool drain to an open drain which is below the inlet connection of

the Quick Cool Coil to ensure that the Quick Cool Coil is completely drained when the

cooling water supply is turned off and the pump is vented to atmosphere.

1.2.6 Electrical Connections

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 warning and caution labels.

❑

Always break the primary circuit of the power supply when

direct access to the heater or wring is required.

Read the safety section in the front of this manual.

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.

1. Verify the heater rating by measuring the resistance of the heater circuit and comparing

it to the values in Table 1-1 on page 19.

2. Make the electrical connections in the junction box located near the foreline. The

electrical supply should not be more than ±5% of the rated voltage.

CAUTION

All electrical connections should be made by qualified

personnel in accordance with all applicable state, local, and/or

industrial codes.

3. Connect the ground earth wire directly to the ground stud. The wire must be terminated

in a double crimp closed loop/ring connector. The connector must be placed over the

ground stud and secured by a lock washer and nut.

4. Connect the two line input wires to terminal positions L1 and L2. For added safety, to

prevent wires from becoming disconnected, secure the two line input wires together

inside the junction box with a tie-wrap, similar to what was done with the heater wires

on the other side of the terminal block.