Monaco 2009 Knight, Owner'S Manual

Page: 199 / 260

19
2009
K
night
Electrical Sy
stems - Chassis - 9
Heater: The heater warms the air in the dash
area. Much like the refrigeration side of the
system, a liquid will be used in the process.
This liquid is the engine coolant. The coolant
is passed from the radiator to an electronic
water valve. When open, the water valve will
allow the coolant to flow through the heater
core. The heater core is much like a miniature
radiator. Air is drawn into the system by a
blower motor through the outside recirculation
door opening. Air is blown through the A/C
evaporator core and then through the heater
core. When the temperature control is in the
WARM position coolant flows through the
heater core. When the temperature is in the
COOL position coolant flow bypasses the
heater core. In either position, the airflow is
felt at the discharge vents.
Electric Water Valve: The water valve
controls the water flow to the heater core.
Functional Test:
Start and operate the engine until
the water reaches normal operating
temperature.
Set the HVAC temperature control to
the full hot position.
The discharge air outlets should have
hot air.
Rotate the temperature control to full
cold position.
Allow 10 minutes for the temperature
to stabilize.
The discharge air outlets should have
cold air.
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System Components
Compressor - The compressor is
belt driven from the engine through
the compressor and electronic clutch
pulley. The compressor will pump
freon from a low-pressure gas into a
high-pressure, high-temperature gas.
This is the start of the refrigeration
process.
Condenser - The condenser is made
of coils and fins which provide rapid
transfer of heat from the refrigerant
as external air passes over the coils.
The high-pressure gas is changed to a
high-pressure liquid.
Condenser Fan -
A steady flow of
cooling air is maintained across the
condenser during system operations.
Receiver-Drier - Refrigerant leaves
the condenser, enters the receiver-drier
and is stored until needed. The drier
filters out moisture in the system. It
only takes one drop of moisture to
cause a malfunction in the cooling unit.
Expansion Valve - The expansion
valve suppresses the refrigerant into
the evaporator according to the cooling
requirements. The pressure is reduced
in the restrictive effort of the expansion
valve. A part of the valve is the
capillary tube assembly. The capillary
tube is the sensing bulb at the outlet of
the evaporator.
Evaporator -
A tube core and fins are
used in the evaporator similar to the
condenser. Air is blown through the
fins to allow the evaporator to cool and
reduce pressure.
Blower and Motor - The evaporator
has a fan called the blower. The
blower will draw air from the cab area
and force the air over the evaporator
coils and fins. This forced air will
ensure continuous vaporizing of the
refrigerant.
Relays and Switches -
Both electronic
and vacuum switches are used in the
control and operations of the system.
Vacuum Generator - The vacuum
generator, located at the front firewall,
is important to the operation of the
dash heating and A/C systems. This
provides the vacuum to open and close
the vacuum switches. The vacuum
generator creates 15 inches of vacuum
that is passed to a reservoir ball. Most
dash heater and A/C systems will
only require 10 inches of vacuum
to operate the switches. The output
from the reservoir is sent to the vent
control knob. The control knob will
then direct the vacuum operation to
the appropriate vacuum switch to open
or close vents and switches. When the
ignition is on and the A/C is operating,
the vacuum generator will operate.