Training Syllabus to Instruct/Prepare for the ASE Transit Bus HVAC Test

Transcription

1 APTA STANDARDS DEVELOPMENT PROGRAM RECOMMENDED PRACTICE American Public Transportation Association 1666 K Street, NW, Washington, DC, APTA BTS-BMT-RP Approved October, 2010 APTA Bus Maintenance Training Working Group Training Syllabus to Instruct/Prepare for the ASE Transit Bus HVAC Test Abstract: This Recommended Practice provides guidelines for establishing a standardized bus maintenance training related to the ASE certification program syllabus for HVAC systems used in transit buses and coaches. Keywords: air conditioning, Automotive Service Excellence (ASE) H7, bus, certification, heating, HVAC, training, transit, ventilation Summary: This Recommended Practice allows users to instruct/prepare transit bus technicians and mechanics for the National Automotive Service Excellence (ASE) H-7 Transit Bus HVAC Test and to evaluate, develop or enhance current training programs for the diagnosis, repair and maintenance of transit bus HVAC systems. Individual operating agencies should modify these guidelines to accommodate their specific equipment and mode of operation. Scope and purpose: This Recommended Practice reflects the consensus of the APTA Bus Standards Program members in conjunction with transit labor organizations, including ATU and TWU, on the subject material, manuals and textbooks, test equipment, methods and procedures that have provided the best performance record based on the experiences of those present and participating in meetings of the program task forces and working groups. APTA recommends the use of this document by organizations that have a training department or conduct training for the maintenance of transit buses, organizations that contract with others for transit bus maintenance training, and organizations that influence how training for transit bus maintenance is conducted. This Recommended Practice represents a common viewpoint of those parties concerned with its provisions, namely, transit operating/planning agencies, manufacturers, consultants, engineers and general interest groups. The application of any standards, practices or guidelines contained herein is voluntary. In some cases, federal and/or state regulations govern portions of a rail transit system s operations. In those cases, the government regulations take precedence over this standard. APTA recognizes that for certain applications, the standards or practices, as implemented by individual rail transit agencies, may be either more or less restrictive than those given in this document.

2 Contents 1. xx... Error! Bookmark not defined. Participants The American Public Transportation Association greatly appreciates the contributions of the Bus Transit Standards Bus Maintenance Training Working Group, which provided the primary effort in the drafting of this Recommended Practice. References... Error! Bookmark not defined. Definitions... Error! Bookmark not defined. Abbreviations and acronyms... Error! Bookmark not defined American Public Transportation Association

3 1. Learning environment For best application of this Recommended Practice, a combination of classroom lectures, mentoring, practical training and practice tests should be included in the training program. 2. Computer skills Basic computer skills are now a standard for transit bus technicians. Basic skills and knowledge in the operation of a computer in a Microsoft Windows environment is essential. 3. Questions format In order to standardize the question-and-answer format, the ASE format of questions has been adopted. This type of test uses six question formats, discussed in the following sections. 3.1 Direct question The correct answer, one out of four potential answers, must be chosen to answer a direct question. 3.2 Completion question The correct answer, out of four potential answers, must be chosen to complete the statement. 3.3 Illustrated question Referring to an illustration, the correct choice must be indicated. 3.4 Technician A and Technician B with stem With this question, the choice is made as to which technician statement is correct, or if both technician statements are correct or incorrect. A lead-in or descriptive statement prefixes the statements 3.5 Technician A and Technician B without stem With this question, the choice is made as to which technician statement is correct, or if both technician statements are correct or incorrect. 3.6 Except This type of question is sometimes referred to as a negative question because the choice is the incorrect answer. In the answers presented to the question or statement, all of them can be correct EXCEPT one. In this type of question, the word EXCEPT will be capitalized. 4. ASE course tasks Tasks that should be covered in this training course: 2010 American Public Transportation Association 1

4 5. Course descriptions and objectives Transit Bus HVAC 101 SAFETY, COMPLIANCE & CERTIFICATION Demonstrate use of proper PPE for working with refrigerants Describe proper handling and labeling of refrigerant storage tanks 101 THEORY & UNDERSTANDING Refer to manufacturer s specifications and codes Demonstrate ability to reference maintenance manuals Demonstrate ability to identify HVAC system components Describe characteristics of different refrigerants Locate heater and defroster core components Demonstrate ability to reference recovery machine operation manuals Demonstrate ability to reference maintenance manual to determine which accessories and components are present Explain the difference between recycling and recovering Explain the operation of heating systems Explain the operations of evaporator and condenser fan motors Demonstrate ability to identify and use the correct containers for different refrigerants 101 TOOL USAGE & DIAGNOSTICS Demonstrate ability to use digital multimeter (DMM) Demonstrate ability to use hand tools properly Demonstrate basic computer skills Demonstrate ability to use basic air tools 102 SAFETY, COMPLIANCE & CERTIFICATION Identify safety/high pressure protection devices Refer to EPA required records on use of refrigerant Describe all EPA requirements for handling, labeling and storage ASE Task Reference A1 B1(6) ASE Task Reference B2(8), D1(1), D1(6), D2(2), D2(3), D2(4), D2(6) E6, B2(3) E2 C11 E1 D2(1) E3 C1 D1(5) E4 ASE Task Reference B2(1), B2(2), B2(6), B2(8), C13,, D1(1), D1(2), D1(3), D1(5), D2(6) B2(2), B2(4), B2(7) A4 B2(6), B2(8), C13 ASE Task Reference B2(1), B2(2) E4 E American Public Transportation Association 2

5 Transit Bus HVAC Comply with federal and local laws concerning handling of refrigerants 102 THEORY & UNDERSTANDING Ability to read pressure temperature charts Identify color code for refrigerant tanks Describe the need for the different refrigerant oil types Locate and describe the purpose of HVAC control panels using schematics and manuals Describe cable operation, check and replace cables as needed Explain compressor operation, hi-lo cut out switches and other related components Explain different uses of AC and DC motors Explain the purpose of evaporator pressure regulators Explain evaporator and condenser operation and purpose Explain the function of expansion valves, service valves, check valves Describe the process of HVAC air flow through bus Explain operation of expansion valve Describe refrigerant color code conventions Explain the use of vacuum pump Describe the operation of the service valve 102 PROCEDURES, INSPECTIONS & TESTING Inspect belts for tension and wear Inspect evaporator filters Check for smooth operation of cables and linkages Demonstrate ability to cut and crimp wires Demonstrate ability to use proper coolant specifications when refilling 103 SAFETY, COMPLIANCE & CERTIFICATION Attain EPA 608 certification Attain EPA 608 Type II certification 201 THEORY & UNDERSTANDING Demonstrate ability to follow proper PM E6 ASE Task Reference B2(1) B1(2) B1(9) D1(6) D2(2), D2(3) B2(2) D1(5) D2(2) D2(3) D1(5) D2(2), D2(3) D2(4) B3(6) E4 B1(6) B1(6) A1 C14 C13 C8 B2(6), B3(5) C American Public Transportation Association 3

6 Transit Bus HVAC Identify gauges needed for proper refrigerant Identify and use the proper refrigerant Describe defroster operation and connection to the rest of the system Demonstrate ability to use manufacturer specifications for lubricant and level 201 TOOL USAGE & DIAGNOSTICS Demonstrate ability to identify refrigerant types using an analyzer or static gauge Demonstrate use of digital thermometer to verify thermostat settings Demonstrate use of test kit for antifreeze to determine conditioner concentration Demonstrate ability to use spectrometer to check antifreeze level 201 PROCEDURES, INSPECTIONS & TESTING Bleed air according to specifications Check air flow Check ambient air sensors above condenser Check condition of belt and pulley Check air flow of blowers Check brackets for looseness Check brackets and clamps to ensure they are not rubbing Check condenser and fittings for leaks Check condenser for debris and dirt Check coolant filter Check discharge line for low discharge temperature Check electrical connections and brushes in fan motor Check evaporator and condenser fans for proper air flow Check fan speed Check fan speed switches Check filter-drier for leaks Check for bent fins Check brackets and mounting bushings Check for bent cage or (squirrel cage) Check for clutch cycling Check for coldwater leaks B1(8) D1(2) B2(5), B1(2) C7, D2(2) C3 C5 C8 B3(3), C1 C1 C6 C13 C5 B3(2) B3(4) B3(3) C3, B1(4) B3(3) B3(3) C1, C2, C3 C13 B3(5) B3(3), B3(7) B3(7) B3(3) A1 C American Public Transportation Association 4

7 Transit Bus HVAC Check for compressor noise Check for moisture and/or contamination of system with site glass and/or gauges Check for discharge air circulation Check for discoloration of compressor oil in sight glass and level Check for electrical smell or rubber burning smell Check for fan motor operation Check for foggy windows Check for frost on drier or tank Check for leaks Check operation of valves Check for return air circulation Check for unusual noise or vibration Check fresh air damper Check heater core for leaks Check hoses, lines and filters for leaks with leak detector, dirt tracks or soapy water. Check inline valves for proper operation and leaks Check low level sensor Check modulation valve for proper operation Check mounting brackets Check mounting bushings Check operation for low air flow Check operation of high pressure relief valve Properly torque clamps Check packing for service valves Check proper placement and contact of thermal bulb Check proper routing of hoses Check return lines for heat Check site glass to ensure proper oil level Check suction line for frost Check temperature of return line Check operation of driver control switches Check that evaporator is engaging to remove moisture Check booster pump operation Check the water pump drive gear Check the relief pressure of the valve A1, B1(3), B1(4) A1, B3(5) B3(7) B3(9) A1 D2(4) C2 B1(5), B3(2) C14 C3 C1 B3(5) B3(4) B3(7) B3(10) C4 B3(9) B3(6) B3(2), C4 B3(10) B3(1), B1(4) C10 C13 C2 C1, C12 C6 C American Public Transportation Association 5

8 Transit Bus HVAC Check the weep hole in the water pump Check thermostat operation Check valve solenoid function Check roof mounted accessories for leaks Clear water drains Unplug drains as needed Clean evaporator core Inspect compressor mounts Inspect remote (feeler) bulb for proper placement and attachment Listen for bearing noise Listen for excessive noise from compressor bearing and tensioner bearing Perform pressure test Pressurize cooling system Remove and clean filter Remove black mold from duct work Test fan operation by turning up temperature Run system to stabilize for 15 minutes Troubleshoot thermostat, connections, cables Verify bolt on expansion valve is attached to line Visually check mountings Visual inspection of oil condition and color Visually check fan components Visually check hoses for leaks, fraying and 'carcass strength' Visually check housing and seals Visually check radiator fins for leaks and bends Visually inspect condition of heater and defroster cores Visually inspect sensors for proper connection or damage 202 SAFETY, COMPLIANCE & CERTIFICATION Demonstrate ability to safely use recycle/recovery machine 202 THEORY & UNDERSTANDING Interpret micron gauge readings Describe manufacturer charging procedures and specifications C6 C3 C15 D2(4) B3(8) C2 B3(7) B2(3) B3 C6 B2(3) C4, C5, C10 C3 B3(8) C16 C9 B3(1) C1 B3(4) B2(5) C9 C4 C7 C5, C11 B2(2) B1(2), B1(6), B2(6), B3(2), B3(5), E3 B1(6) B1(8) 2010 American Public Transportation Association 6

9 Transit Bus HVAC Read and interpret schematic diagrams Describe HVAC control systems 202 TOOL USAGE & DIAGNOSTICS Demonstrate ability to use electronic sniffer Demonstrate ability to use micron gauge Demonstrate ability to use nitrogen as a drying agent Demonstrate ability to use manifold gauges Connect gauges to check pressures, test on or off bus as needed Connect manifold gauge and interpret pressures based on refrigerant used Install manifold gauge set Demonstrate ability to use a purge machine Purge manifold gauge set Demonstrate ability to service and maintain recycle/recovery machine Demonstrate ability to use a digital thermometer and pressure gauge to confirm presence of noncondensable gases Demonstrate ability to use belt tension gauge for proper belt tension adjustment Demonstrate ability to use flow meters Demonstrate ability to use service valves to isolate system Demonstrate ability to use strobe to check fan speed 202 PROCEDURES, INSPECTIONS & TESTING Demonstrate ability to check refrigerant level Demonstrate ability to do nitrogen pressure test Demonstrate ability to weigh added refrigerant Demonstrate ability to align compressor pulleys with straight edge Change compressor oil Change evaporator core Check air gap on compressor clutch Check clutch mating surfaces for wear and straightness Check engine temperature sensor Check for compressor operation Check for electrical and mechanical failures of the coolant valves B2(1), B2(6), B3(4), D1(1), D1(2), D1(6) B1(1) B1(5) B1(6), B3(2), B3(5) B1(6) B1(6), B1(8), B2(1), B2(2), B2(6), E3 D1(3), D1(5), D2(1) B3 E1, B1(3) B1(6) E5 B2(3) D2(3) B2(6) C9 B2(1), B1(3), B1(8) B1(3) B1(8) B2(3) B2(5) B3(7) B2(4) B2(4) D1(4) B3(10) D2(3) 2010 American Public Transportation Association 7

10 Transit Bus HVAC Check grounds Check heater control valve Check mechanical control panel assembly Check modulator valve Check safety switches Check the heating modulation valves Check unloaders and valves Check operation of evaporator pressure regulator Connect temperature sensor to evaporator outlet Confirm operation of condenser fans Confirm proper airflow through condenser Connect sensors to return air duct and discharge air Connect temperature sensors Inspect hardware and adjust or replace as needed Locate and test heater core sensor Locate valves and visually check for leaks Demonstrate ability to splice or solder properly Demonstrate ability to use ambient air temperature to determine pressures Demonstrate ability to use R22 mixed with nitrogen gas to check for leaks Perform Visual/tactile inspection of pipes to check coolant valve function 203 TOOL USAGE & DIAGNOSTICS Demonstrate ability to diagnose electrical problems with clutch coil Demonstrate ability to properly diagnosis condenser fan motors Demonstrate ability to use digital multimeter to measure clutch coil resistance and running voltage & amperage 203 PROCEDURES, INSPECTIONS & TESTING Demonstrate ability to clean expansion valve filter Check electronic display panel for codes Check operation of evaporator and condenser fan motors (speed, current draw, and proper air flow) D1(1), D1(6) D2(2), D2(3) D2(2), D2(3) D1(4) D2(1) B3(10) B2(6), D2(1) B1 B3(10) B3(10) B2(7) B3(9) B2(2) B3(2) D2(3) B2(1) B2(1) B2(4) B1(7), B3(6) B2(1) B1(1) 2010 American Public Transportation Association 8

11 Transit Bus HVAC 301 THEORY & UNDERSTANDING Demonstrate ability to interpret refrigeration gauge readings Describe electrical and mechanical protection devices for different manufacturers 301 TOOL USAGE & DIAGNOSTICS Properly connect and use readers or laptop depending on manufacturer Identify HVAC fault codes Electronically diagnose solenoid operation Measure for superheat Perform refrigerant oil acid test and interpret results 301 PROCEDURES, INSPECTIONS & TESTING Demonstrate ability to check motor RPMs 302 TOOL USAGE & DIAGNOSTICS Check and interpret diagnostic codes Clear fault codes Diagnose function of relay boards or control boards Use laptop software to open and close valves (where electronically controlled) 302 PROCEDURES, INSPECTIONS & TESTING Adjust set point Adjust system parameters Interpret sensor readings and compare to specifications B1(8) D1(3), D1(5) A4, B2(1), B2(2), B2(8), D1(1), D1(4), D1(6), D2(1), D2(2), D2(5), D2(6), D2(7) A4 B3(6) B3(6) B3(3) D2(1), D2(2), D2(5), D2(6), D2(7) A4 D1(6) D2(4) A4 A4 B2(1) 2010 American Public Transportation Association 9

12 Transit Bus HVAC 303 THEORY & UNDERSTANDING Explain connections/interface between HVAC and bus multiplexing 303 TOOL USAGE & DIAGNOSTICS Demonstrate ability to download program and set parameters Diagnose zone heating and cooling problems 303 PROCEDURES, INSPECTIONS & TESTING Identify and replace faulty modules, program new modules based on local specifications Inspect and calibrate temperature sensors (temperature) 401 TOOL USAGE & DIAGNOSTICS Demonstrate ability to use laptop computer to diagnose auxiliary heater 401 PROCEDURES, INSPECTIONS & TESTING Check for hose leaks on coolant side Check fuel pump and nozzle for proper operation Check igniter gap Check testing switch Clean heat exchanger as recommended Clean optical sensor Change fuel filter D1(2), D1(4) B1(1) D2(4) D1(1), D1(6) B1(1) 6. Exam requirements The minimum acceptable grade to pass the course and all practical tests is 75 percent. Students must pass written tests with a minimum grade of 80 percent American Public Transportation Association 10

13 References National Institute for Automotive Service Excellence (ASE) website. Abbreviations and acronyms AC APTA ASE ATU DC DMM EPA HVAC PM PPE RPM TWU alternating current American Public Transportation Association Automotive Service Excellence Amalgamated Transit Union direct current digital multimeter Environmental Protection Agency heating, ventilation and air conditioning Preventive Maintenance personal protective equipment revolutions per minute Transit Workers Union 2010 American Public Transportation Association 11