Severn Trent VAX4600 Series, Instruction Manual

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115.6001.10

4.6

 Water Temperature Control Thermostat (Refer to Bulletins 115.3020 and 115.3021)

4.6.1

Check power source and fuse to actuate magnetic contactor coil.

4.6.2

Check power source and fuse to heater circuit.

4.6.3

Check power source and 100 mA sloblow fuse to the temperature control.

WARNING

: Improper voltage will destroy the switch.

4.6.4

Check contactor for malfunction. Refer to manufacturer’s instructions.

4.6.5

Check low water level cutoff. Section 4.5.

4.6.6

Check high water temperature alarm, Section 4.7.

4.6.7

Manually check water temperature to confirm failure of thermostat to actuate.

4.6.8

Refer to Shutdown Section before proceeding.

4.6.9

Disconnect wiring and remove control thermostat.

4.6.10 Refer to Startup Section.

4.7

High and Low Water Temperature Alarm Switch

4.7.1

Check power source and fuse.

4.7.2

Inspect the actuated component for proper operation. Refer to manufacturer’s instructions.

4.7.3

Manually check water temperature to confirm failure of switch to actuate.

4.7.4

Refer to Shutdown Section.

4.7.5

Disconnect wiring and remove switch.

4.7.6

Replace using a Teflon based pipe dope or Teflon tape on the threads.

4.7.7

Refer to Startup Section.

The temperature controls are factory set as follows:

Control Thermostat - 180°F (82°C)

Low Temperature Alarm Switch - 170°F (77°C)

High Temperature Alarm Switch - 190°F (88°C)

4.8

Cathodic Protection - Anode Replacement

The water wetted surfaces of the vaporizer are protected against corrosion by two sacrificial anodes. The anodes
being the most active metal in the vaporizer will suffer corrosion and supply the electrical current needed to
protect the structure.

The anodes should be replaced as a set after they are consumed. This is indicated by zero current flow at all
potentiometer settings. Refer to Figure 8 and proceed as follows to replace or remove the anodes. Note: It is not
necessary to shutdown the system for this procedure, but caution must be exercised to prevent burns from the
hot water in the tank.

4.8.1

To replace the anode, disconnect the wire from the screw at the top of the anode. See Figure 8. Using a
screwdriver, hold the position of the screw and loosen the nut with a box wrench.

4.8.2

Unscrew the two 10-24 screws at the top plate and withdraw the anode insulator vertically from the
vaporizer.

4.8.3

Insert a new anode and fasten into position.

4.8.4

Connect wires as before. The screw at the top of the anode must be tight and in good electrical contact.

4.9

Recommended Torque Values

The following bolt/nut torque values are used at the factory when assembling the equipment. These values are
recommended guidelines for re-assembly of a repaired unit:

Part

Torque Value

Flange Bolt

110 foot pounds

Thermowell

75 foot pounds