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HEATING, VENTILATION, & AIR CONDITIONING
For every task in Heating, Ventilation, and Air Conditioning, the following
safety task must be strictly enforced:
Comply with personal and environmental safety practices associated with clothing;
eye protection; hand tools; power equipment; proper ventilation; and the handling,
storage, and disposal of chemicals/materials in accordance with federal, state,
and local regulations.
The first task in Heating, Ventilation, & Air Conditioning is to listen
to and verify the operator's concern, review past maintenance and repair documents,
and determine necessary action.
VII. HEATING, VENTILATION, & AIR CONDITIONING
All practices and procedures must be performed according to current mandates,
standards, and regulations.
A. HVAC Systems Diagnosis, Service, and Repair
1. Verify the need for service or repair of HVAC systems based on unusual operating
noises; determine needed action. P-1
2. Verify the need of service or repair of HVAC systems based on unusual visual,
smell, and touch conditions; determine needed action. P-1
3. Identify system type and components (cycling clutch orifice tube - CCOT,
expansion valve/R-12, R-134a) and conduct performance test(s) on HVAC systems;
determine needed action. P-1
VII. HEATING, VENTILATION, & AIR CONDITIONING
B. A/C System and Component Diagnosis, Service, and Repair
1. A/C System - General
1. Diagnose the cause of temperature control problems in the A/C system; determine
needed action. P-1
2. Identify refrigerant type and check for contamination; determine needed action.
P-2
3. Diagnose A/C system problems indicated by pressure gauge readings; determine
needed action. P-1
4. Diagnose A/C system problems indicated by visual, audible, smell, and touch
procedures; determine needed action. P-1
5. Perform A/C system leak test; determine needed action. P-1
6. Evacuate A/C system using appropriate equipment. P-1
7. Internally clean contaminated A/C system components and hoses. P-3
8. Charge A/C system with refrigerant. P-1
9. Identify lubricant type needed for system application. P-1
B. A/C System and Component Diagnosis, Service, and Repair
2. Compressor and Clutch
1. Diagnose A/C system problems that cause protection devices (pressure, thermal,
and electronic) to interrupt system operation; determine needed action. P-1
2. Inspect, test, and replace A/C system pressure, thermal, and electronic protection
devices. P-2
3. Inspect, adjust, and replace A/C compressor drive belts, pulleys, and tensioners.
P-1
4. Inspect, test, service, and replace A/C compressor clutch components or assembly.
P-2
5. Inspect and correct A/C compressor lubricant level (if applicable). P-2
6. Inspect, test, and replace A/C compressor. P-3
7. Inspect, repair, or replace A/C compressor mountings and hardware. P-3
VII. HEATING, VENTILATION, & AIR CONDITIONING
B. A/C System and Component Diagnosis, Service, and Repair
3. Evaporator, Condenser, and Related Components
1. Correct system lubricant level when replacing the evaporator, condenser,
receiver/drier or accumulator/drier, and hoses. P-1
2. Inspect A/C system hoses, lines, filters, fittings, and seals; determine
needed action. P-1
3. Inspect A/C condenser for proper air flow. P-1
4. Inspect and test A/C system condenser and mountings; determine needed action.
P-2
5. Inspect and replace receiver/drier or accumulator/drier. P-1
6. Inspect and test cab/sleeper refrigerant solenoid, expansion valve(s); check
placement of thermal bulb (capillary tube); determine needed action. P-3
7. Inspect and replace orifice tube. P-1
8. Inspect and test cab/sleeper evaporator core; determine needed action. P-3
9. Inspect, clean, and repair evaporator housing and water drain; inspect and
service/replace evaporator air filter. P-1
10. Identify and inspect A/C system service ports (gauge connections); determine
needed action. P-1
11. Diagnose system failures resulting in refrigerant loss from the A/C system
high pressure relief device; determine needed action. P-2
VII. HEATING, VENTILATION, & AIR CONDITIONING
C. Heating and Engine Cooling Systems Diagnosis, Service, and Repair
1. Diagnose the cause of outlet air temperature control problems in the HVAC
system; determine needed action. P-1
2. Diagnose window fogging problems; determine needed action. P-2
3. Perform engine cooling system tests for leaks, protection level, contamination,
coolant level, temperature, and conditioner concentration; determine needed
action. P-1
4. Inspect engine cooling and heating system hoses, lines, and clamps; determine
needed action. P-1
5. Inspect and test radiator, pressure cap, and coolant recovery system (surge
tank); determine needed action. P-1
6. Inspect water pump and drive system; determine needed action. P-2
7. Inspect and test thermostats, by-passes, housings, and seals; determine needed
repairs. P-2
8. Flush and refill cooling system; bleed air from system. P-1
9. Inspect and test fan, fan hub, fan clutch, fan controls, fan thermostat,
and fan shroud; determine needed action. P-2
10. Inspect and test heating system coolant control valve(s) and manual shut-off
valves; determine needed action. P-2
11. Inspect and flush heater core; determine needed action. P-2
VII. HEATING, VENTILATION, AND AIR CONDITIONING
D. Operating Systems and Related Controls Diagnosis and Repair
1. Electrical
1. Diagnose the cause of failures in HVAC electrical control systems; determine
needed action. P-1
2. Inspect and test A/C heater blower motors, resistors, switches, relays, modules,
wiring, and protection devices; determine needed action. P-2
3. Inspect and test A/C compressor clutch relays, modules, wiring, sensors,
switches, diodes, and protection devices; determine needed action. P-2
4. Inspect and test A/C-related electronic engine control systems; determine
needed action. P-2
5. Inspect and test engine cooling/condenser fan motors, relays, modules, switches,
sensors wiring, and protection devices; determine needed action. P-2
6. Inspect and test electric actuator motors, relays/modules, switches, sensors,
wiring, and protection devices; determine needed action. P-3
7. Inspect and test HVAC system electrical control panel assemblies; determine
needed action. P-3
2. Air/Vacuum/Mechanical
1. Diagnose the cause of failures in HVAC air, vacuum, and mechanical switches
and controls; determine needed action. P-1
2. Inspect and test HVAC system air/vacuum/mechanical control panel assemblies;
determine needed action. P-3
3. Inspect, test, and adjust HVAC system air/vacuum/mechanical control cables
and linkages; determine needed action. P-3
4. Inspect and test HVAC system vacuum actuators (diaphragms/motors) and hoses;
determine needed action. P-3
5. Inspect and test HVAC system vacuum reservoir(s), check valve(s), and restrictors;
determine needed action. P-3
6. Inspect, test, and adjust HVAC system ducts, doors, and outlets; determine
needed action. P-3
E. Refrigerant Recovery, Recycling, and Handling
NOTE: Tasks 1 through 5 should be accomplished in accordance with published
EPA and appropriate SAE "J" standards for R-12, R-134a, and EPA approved
refrigerant blends.
1. Maintain and verify correct operation of certified equipment. P-1
2. Identify (by label application or use of a refrigerant identifier) and recover
A/C system refrigerant. P-1
3. Recycle refrigerant. P-1
4. Handle, label, and store refrigerant. P-1
5. Test recycled refrigerant for non-condensable gases. P-1
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