|
| |
TM5-4120-376-14
d. Mode Selector Switch. The mode selector switch is an electrical switch that can be
manually positioned to select the desired operational mode of the air conditioner. The five
positions of the mode selector are:
(1) Off. The off mode position is used to stop operation. All major electrical components
are isolate from electrical power except the compressor crankcase heater, which is
thermostatically controlled as long as input power is connected to the unit.
(2) Vent. In the vent mode position, the evaporator motor operates and the fans circulate
filtered air. Ventilation air will be drawn into the unit through the fresh air filter and vent duct
if the damper door in the vent duct is open. Some cooling effect will occur if the ventilation
air is cold. Ventilation air flow is controlled by opening and closing the damper door with the
vent adjusting knob.
(3) Cool. In the cool mode position, the refrigerant cycle begins, and the unit will cool.
Ventilation air will be drawn into the unit if the vent damper door is open.
(4) Low Heat. In the low heat mode, the evaporator fan motor operates continuously and
three of the six heater elements are activated. The three heater elements cycle on and off
under thermostatic control of the temperature selector switch. This mode will produce half of
the unit's heating capability. Ventilation air will be drawn into the unit if the vent damper door
is open.
(5) High Heat. In the high heat mode, the evaporator fan motor operates continuously
and all six of the heater elements are activated, but only three of the heater elements will cycle
on and off under thermostatic control of the temperature selector switch. This mode will
produce maximum heating capability of the unit. Ventilation air will be drawn into the unit if
the vent damper door is open.
e. Evaporator Fan Speed Switch. The evaporator fan speed switch has two positions, “low”
and “high”. The positions are manually selected to control the evaporator fan speed in all
operating modes. Normally the “low” speed should be selected as it is quieter and requires less
electrical power; however, the “high” speed position has three advantages over “low” which may
dictate its selection:
(1) Maximum cooling capacity can only be achieved in “high”.
(2) The increased flow of evaporator air improves air distribution in the conditioned
space.
(3) Twice as much ventilation air is drawn into the unit in “high”.
f. Ventilation Knob. The ventilation knob controls the flow of ventilation air into the unit.
The knob is connected by the damper cable to a damper located in the vent duct. The knob
controls the flow of ventilation air by adjusting the position of the damper from full closed to
full open. Turning the knob to the right closes the damper, turning the knob to the left opens
the damper. When ventilation air enters the air conditioned space a like flow of air must
exhaust from the space to prevent a pressure buildup. Cracks in the space may be sufficient;
but if a large flow of ventilation air is desired, some positive means of air exhaust should be
provided.
g. Return Air Louver. The return air louver is finger-adjustable from full open to full closed.
Normally the louver shutter tab adjustment is kept at 45 position, which is essentially the
same as a full open return air louver. If the return air louver is closed, return air will still
2-2
|
