Oct 04, 2022  
2017-2018 
    
2017-2018 [ARCHIVED CATALOG]

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

Credits: 4


Introduces and practices the service of heavy duty diesel vehicle heating, ventilation, and air conditioning (HVAC) systems. Practices NATEF tasks related to HVAC systems of heavy duty diesel vehicle.

Prerequisite(s): HDD 202  and HDD 206  both with a minumum grade of "C" (2.0)
Corequisite(s): HDD 203W , HDD 209W , and HDD 210  
Lecture Hours: 60 Lab Hours: 30
Meets MTA Requirement: None
Pass/NoCredit: Yes

Outcomes and Objectives 1:    Complete general HVAC system diagnosis and related NATEF tasks as listed below.

     A.          Verify the need for service or repair of HVAC systems based on unusual operating noises; determine needed action.

     B.          Verify the need for service or repair of HVAC systems based on unusual visual, smell, and touch conditions; determine needed action.

     C.          Identify system type and components (cycling clutch orifice tube – CCOT, expansion valve) and conduct performance test(s) on HVAC
                   systems; determine needed action.

     D.          Retrieve diagnostic codes; determine needed action.

2.    Complete NATEF tasks related to A/C System and Components as listed  below.

     A.          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.

     B.          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.

     C.          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.

     A.          Identify causes of outlet air temperature control problems in the HVAC system; determine needed action.

     B.          Identify window fogging problems; determine needed action.

     C.          Perform engine cooling system tests for leaks, protection level, contamination, coolant level, coolant type, temperature, and conditioner
                   concentration; determine needed action.

     D.          Inspect engine cooling and heating system hoses, lines, and clamps; determine needed

     E.          Inspect and test radiator, pressure cap, and coolant recovery system (surge tank); determine needed action.

     F.           Inspect water pump; determine needed action.

     G.          Inspect and test thermostats, by-passes, housings, and seals; determine needed repairs.

     H.          Recover, flush, and refill with recommended coolant/additive package; bleed cooling system.

     I.            Inspect thermostatic cooling fan system (hydraulic, pneumatic, and electronic) and fan shroud; replace as needed.

     J.           Inspect and test heating system coolant control valve(s) and manual shut- off valves; determine needed action.

     K.           Inspect and flush heater core; determine needed action.

 4.    Complete NATEF tasks related to Operating Systems and Related Controls as listed below.

     A.          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.

     B.          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 Refrigerante Recovery, Recycling, and

     A.          Maintain and verify correct operation of certified equipment.

     B.           Identify and recover A/C system refrigerant.

     C.           Recycle or properly dispose of refrigerant.

     D.           Handle, label, and store refrigerant.

     E.           Test recycled refrigerant for non-condensable gases.



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