Block I – Climate Control

Trends

Climate control systems have become more complex. Because of environmental concerns, regulations governing the use of refrigerants have become stricter and more consistently enforced. Product tracking has become a common industry practice. More HVAC systems are ECM controlled.

Related Components (including, but not limited to)

Heating and ventilation system: ductwork, motors, blowers, pumps, resistors, controls, modules, heater cores, hoses, fittings.

Air conditioning system: evaporator, condenser, compressor, receiver dryer, expansion valves, sensors, controls, hoses, fittings, orifice tubes, accumulators, switches.

Tools and Equipment

See Appendix A.

Task 36 Services, diagnoses and repairs heating and ventilation systems.

Context

Truck and transport mechanics service, diagnose and repair heating and ventilation systems for the comfort of the driver.

Required Knowledge

• K 1 heating system components such as blowers, pumps, resistors, controls and modules
• K 2 heater operating principles such as coolant flow and heat exchange
• K 3 common heating system faults such as burnt resistors, worn motors and malfunctioning heat controls
• K 4 ductwork components and routing
• K 5 hazards of materials
• K 6 basic principles of electricity and circuit components

Sub-task - I-36.01 Services heating and ventilation systems.

Key Competencies

• I-36.01.01 clean heating and ventilation system components such as filters and heater cores
• I-36.01.02 perform sensory inspections of heating and ventilation system to identify worn, damaged or defective components such bent or plugged fins, burnt heater controls and leaking flow valve
• I-36.01.03 measure heating and ventilation system components such as for air temperature and flow to determine if they meet manufacturers’ specifications
• I-36.01.04 remove and replace consumable components such as coolant according manufacturers’ specifications
• I-36.01.05 recycle and/or dispose of coolant according to jurisdictional regulations
• I-36.01.06 record service information and inspection findings according to manufacturers’ requirements for warranty, and for future reference and tracking

Sub-task - I-36.02 Diagnoses heating and ventilation systems.

Key Competencies

• I-36.02.01 obtain details of symptoms associated with complaint to establish a starting point for diagnosis
• I-36.02.02 perform sensory inspections such as temperature, coolant leaks and air flow to confirm complaint and establish a preliminary diagnosis
• I-36.02.03 perform diagnostic procedure by following troubleshooting tree or schematic supplied by manufacturer to determine failure
• I-36.02.04 perform testing procedures such as bringing vehicle to operating temperature to assess components for wear, damage or defects such as thermostat failure
• I-36.02.05 test system and component operation to isolate problem
• I-36.02.06 perform failure analysis to determine root cause of failure
• I-36.02.07 record test results and inspection findings according to manufacturers’ requirements for warranty, and for future reference and tracking

Sub-task - I-36.03 Repairs heating and ventilation systems.

Key Competencies

• I-36.03.01 remove and replace worn, damaged or faulty components such as thermostats, blowers, flow valves and heater cores
• I-36.03.02 rebuild components such as heater cores, radiators and heater boxes by replacing parts according to manufacturers’ specifications
• I-36.03.03 repair components such as flow valves by replacing the cable, heater core by soldering components and heater motors by fixing the wiring, according to manufacturers’ specifications
• I-36.03.04 clean and replace filters
• I-36.03.05 adjust cables on flow valves and doors on heater boxes to ensure proper operation of component/equipment
• I-36.03.06 verify repair by using methods such as road testing and sensory observations
• I-36.03.07 document that repairs and verifications have been performed for warranty, liability, future reference and tracking
• I-36.03.08 disassemble and reassemble dashboard and firewall components for access

Task 37 Services, diagnoses and repairs air conditioning systems.

Context

Truck and transport mechanics service, diagnose and repair air conditioning systems for the comfort of the driver.

Required Knowledge

• K 1 heating system components such as blowers, pumps, resistors, controls and modules
• K 2 ductwork components and routing
• K 3 regulations and standards related to air conditioning material handling such as reclaiming, recycling and disposing of material
• K 4 air conditioning system components such as evaporator, condenser, compressor, receiver dryer, expansion valves, sensors and controls
• K 5 air conditioning operating principles and theory (compression and expansion)
• K 6 types of refrigerant oils and refrigerants such as R134A
• K 7 hazards of materials such as refrigerant, and hot and cold temperatures
• K 8 air conditioning electrical components
• K 9 properties, sizes and functions of high/low line side

Sub-task - I-37.01 Services air conditioning systems.

Key Competencies

• I-37.01.01 clean air conditioning system components such as condenser and evaporator cores
• I-37.01.02 perform sensory inspections of air conditioning systems to identify worn, damaged or defective components such chaffed lines, defective expansion valves, plugged condensers and damaged evaporators
• I-37.01.03 measure temperature and air flow of air conditioning system to determine if it meets manufacturers’ specifications
• I-37.01.04 record service information and inspection findings according to manufacturers’ requirements for warranty, and for future reference and tracking

Sub-task - I-37.02 Diagnoses air conditioning systems.

Key Competencies

• I-37.02.01 obtain details of symptoms associated with complaint to establish a starting point for diagnosis
• I-37.02.02 perform sensory inspections of air conditioning systems to identify worn, damaged or defective components such as chaffed lines, defective expansion valves, plugged condensers and damaged evaporators to confirm complaint and establish a preliminary diagnosis
• I-37.02.03 perform diagnostic procedure by following troubleshooting tree or schematic supplied by manufacturer to determine failure
• I-37.02.04 pressure test for high/low pressure to assess components for wear, damage or defects using tools and equipment such as air conditioning recovery machines
• I-37.02.05 perform electrical testing to isolate problem
• I-37.02.06 run system to isolate problem
• I-37.02.07 compare test results to manufacturers’ specifications or expected values to verify diagnosis
• I-37.02.08 perform failure analysis to determine root cause of failure
• I-37.02.09 record test results and inspection findings according to manufacturers’ requirements for warranty, and for future reference and tracking

Sub-task - I-37.03 Repairs air conditioning systems.

Key Competencies

• I-37.03.01 remove and replace worn, damaged or faulty components such as expansion valves, evaporators, belt, condensers and sensors
• I-37.03.02 remove and replace consumables such as freon according manufacturers’ specifications and employer maintenance schedule to minimize breakdowns
• I-37.03.03 adjust freon pressures to ensure proper operation of component/equipment
• I-37.03.04 recycle freon according to jurisdictional regulations using equipment such as air conditioning recovery system
• I-37.03.05 verify repair by running air conditioning system
• I-37.03.06 document that repairs and verifications have been performed for warranty, liability, future reference and tracking
• I-37.03.07 use welding equipment to braze or solder lines
• I-37.03.08 disassemble and reassemble dashboard and firewall components for access, according to manufacturers’ specifications
• I-37.03.09 evacuate, clean and recharge system refrigerant according to manufacturer’s specifications