Hvac System Basic Maintenance; Coil Cleaning; Driver's Unit - PREVOST H3-41 Maintenance Manual

SECTION 22: HEATING AND AIR CONDITIONING
3.

HVAC SYSTEM BASIC MAINTENANCE

Basic maintenance required on the passenger's
and driver's units consists in cleaning their
respective coils and cleaning or replacing air
filters.
However, periodic inspection for broken drains,
hoses and charging of system should be done.
MAINTENANCE
Squeeze rubber discharge tubes located
underneath the appropriate compartment to
eliminate the accumulated water and dirt
every three months.
3.1

COIL CLEANING

Check the external surface of the coils at regular
intervals for dirt or any foreign matter.
3.1.1

Driver's Unit

MAINTENANCE
Once a year, gain access to the driver's unit,
remove the coil access panel (Figure 14) and
clean the driver's unit evaporator and heater
coils with low pressure air jet, taking care not to
damage fins. Clean the bottom of the defrost
plenum.
For the optional windshield upper section
defogger/defroster, remove the bottom access
panel, remove the six bolts fixing the blower
motor assembly. Use low air pressure to clean
the coil.
FIGURE 14: DRIVER'S UNIT AIR FILTERS
20 PA1621 Maintenance Manual All Series | Revised February 2019
3.1.2 Passenger's Unit
With the air filters previously removed, clean
the passenger's unit evaporator and heater
coils with low air pressure or a stream low-
pressure water once a year. Do not use a
pressure washer as this will damage the fins.
Remove the air filter and brush the evaporator
coil from behind.
Once a year, clean the condenser with low-
pressure air jet or a stream of low-pressure
water, taking care not to damage fins (Figure
16).
CAUTION
Direct the pressure straight through the coil to
prevent bending of fins and do not use
extremely high pressure.
water, steam or caustic soap.
FIGURE 15: EVAPORATOR COIL CLEANING WITH LOW-
PRESSURE AIR JET
22171
MAINTENANCE
Do not use hot
22373