Carrier T-326 Fan Speed Switch three speed or variable, Thermostat Control, 2.3.1 ON/OFF Switch

There will be some applications where the switch mounting plate, thermostat and fan speed switch are mounted in the drivers area without the control panel housing.

On other applications the vehicle manufacturer (OEM) will supply different type controls for the air conditioning system. Refer to OEM technical manual for operating instructions.

2.2.1 Fan Speed Switch (three speed or variable)

Turning this switch clockwise will energize the evaporator and condenser fan motors. The compressor clutch will also be energized if the thermostat calls for cooling (see thermostat control operation).

Three Speed --The standard fan speed switch has four settings, Off (0), Low (1), Medium (2), and High (3) speed operation. This switch controls the operation of the system and the evaporator blower(s) by energizing the appropriate circuits and relays located on the electrical control panel.

Variable Speed --Certain applications may be fitted with a variable speed control switch instead of the standard three speed switch. This switch controls the speed of the evaporator motors by varying the supply voltage.

2.2.2 Thermostat Control

The thermostat controls the temperature within the passenger compartment by switching system components on and off.

Rotate the potentiometer switch knob to the right (clockwise) for maximum cooling. Rotate the potentiometer switch knob to the left (counterclockwise) for less cooling.

2.3 DRIVER’S CONTROL PANEL -- FLORIDA (TEMPCON)

This control panel (See Figure 2-2) is normally used in school buses located within the state of Florida, but not limited to that area. This controller is wired to an electrical control board.

The controller consists of:

a.ON/OFF Switch

b.Fan Speed Switch

c.Potentiometer

d.In--Line Fuse (Behind Controller)

2.3.1 ON/OFF Switch

Power is supplied to the controller, through an in--line fuse (see Figure 2-3) from a 12 VDC ignition source originating from the vehicle. The controller will not operate until the ignition switch is activated.

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