HDD 207 - Heavy Duty Diesel Heating, Ventilation, & Air Conditiioning

1. Complete general HVAC system diagnosis and related NATEF tasks as listed below.
   1. Verify the need for service or repair of HVAC systems based on unusual operating noises; determine needed action.
   2. Verify the need for service or repair of HVAC systems based on unusual visual, smell, and touch conditions; determine needed action.
   3. Identify system type and components (cycling clutch orifice tube – CCOT, expansion valve) and conduct performance test(s) on HVAC systems; determine needed action.
   4. Retrieve diagnostic codes; determine needed action.
2. Complete NATEF tasks related to A/C System and Components as listed  below.
   1. A/C System - General
      1. Identify causes of temperature control problems in the A/C system; determine needed action.
      2. Identify refrigerant and lubricant types; check for contamination; determine needed action.
      3. Identify A/C system problems indicated by pressure gauge and temperature readings; determine needed action.
      4. Identify A/C system problems indicated by visual, audible, smell, and touch procedures; determine needed action.
      5. Perform A/C system leak test; determine needed action.
      6. Recover, evacuate, and recharge A/C system using appropriate equipment.
      7. Identify contamination in the A/C system components; determine needed action.
      8. Interface with vehicle's on-board computer; perform diagnostic procedures using recommended electronic service tool(s) (including PC based software and/or data scan tools); determine needed action.
   2. Compressor and Clutch
      1. Identify A/C system problems that cause protection devices (pressure, thermal, and electronic) to interrupt operation; determine needed action.
      2. Inspect, test, and replace A/C system pressure, thermal, and electronic protection devices.
      3. Inspect and replace A/C compressor drive belts, pulleys, and tensioners; adjust belt tension and check alignment.
      4. Inspect, test, adjust, service, or replace A/C compressor clutch components or assembly.
      5. Inspect and correct A/C compressor lubricant level (if applicable).
      6. Inspect, test, or replace A/C compressor.
      7. Inspect, repair, or replace A/C compressor mountings and hardware.
   3. Evaporator, Condenser, and Related Components
      1. Correct system lubricant level when replacing the evaporator, condenser, receiver/drier or accumulator/drier, and hoses.
      2. Inspect A/C system hoses, lines, filters, fittings, and seals; determine needed action.
      3. Inspect and test A/C system condenser. Check for proper airflow and mountings; determine needed action.
      4. Inspect and replace receiver/drier or accumulator/drier.
      5. Inspect and test cab/sleeper refrigerant solenoid, expansion valve(s); check placement of thermal bulb (capillary tube); determine needed action.
      6. Remove and replace orifice tube.
      7. Inspect and test cab/sleeper evaporator core; determine needed action.
      8. Inspect, clean, or repair evaporator housing and water drain; inspect and service/replace evaporator air filter.
      9. Identify and inspect A/C system service ports (gauge connections); determine  needed action.
      10. Identify the cause of system failures resulting in refrigerant loss from the A/C system high pressure relief device; determine needed action.
3. Complete NATEF tasks related to Heating and Engine Cooling Systems as listed below.
   1. Identify causes of outlet air temperature control problems in the HVAC system; determine needed action.
   2. Identify window fogging problems; determine needed action.
   3. Perform engine cooling system tests for leaks, protection level, contamination, coolant level, coolant type, temperature, and conditioner concentration; determine needed action.
   4. Inspect engine cooling and heating system hoses, lines, and clamps; determine needed
   5. Inspect and test radiator, pressure cap, and coolant recovery system (surge tank); determine needed action.
   6. Inspect water pump; determine needed action.
   7. Inspect and test thermostats, by-passes, housings, and seals; determine needed repairs.
   8. Recover, flush, and refill with recommended coolant/additive package; bleed cooling system.
   9. Inspect thermostatic cooling fan system (hydraulic, pneumatic, and electronic) and fan shroud; replace as needed.
   10. Inspect and test heating system coolant control valve(s) and manual shut- off valves; determine needed action.
   11. Inspect and flush heater core; determine needed action.
4. Complete NATEF tasks related to Operating Systems and Related Controls as listed below.
   1. Electrical
      1. Identify causes of HVAC electrical control system problems; determine needed action.
      2. Inspect and test HVAC blower motors, resistors, switches, relays, modules, wiring, and protection devices; determine needed action.
      3. Inspect and test A/C compressor clutch relays, modules, wiring, sensors, switches, diodes, and protection devices; determine needed action.
      4. Inspect and test A/C related electronic engine control systems; determine needed action.
      5. Inspect and test engine cooling/condenser fan motors, relays, modules, switches, sensors, wiring, and protection devices; determine needed action.
      6. Inspect and test electric actuator motors, relays/modules, switches, sensors, wiring, and protection devices; determine needed action.
      7. Inspect and test HVAC system electrical/electronic control panel assemblies; determine needed action.
      8. Interface with vehicle’s on-board computer; perform diagnostic procedures using recommended electronic service tool(s) (including PC based software and/or data scan tools); determine needed action.
   2. Air/Mechanical
      1. Identify causes of HVAC air and mechanical control problems; determine needed action.
      2. Inspect and test HVAC system air and mechanical control panel assemblies; determine needed action.
      3. Inspect, test, and adjust HVAC system air and mechanical control cables and linkages; determine needed action.
      4. Inspect and test HVAC system actuators and hoses; determine needed action.
      5. Inspect, test, and adjust HVAC system ducts, doors, and outlets; determine needed action.
5. Complete NATEF tasks related to Refrigerant Recovery, Recycling, and
   1. Maintain and verify correct operation of certified equipment.
   2. Identify and recover A/C system refrigerant.
   3. Recycle or properly dispose of refrigerant.
   4. Handle, label, and store refrigerant.
   5. Test recycled refrigerant for non-condensable gases.