A/C Maintenance continued
Delaying preventive maintenance
Transit system budgets are under enormous pressure with operators striving to do more with less and stretch every dollar as far as it will go. Every budget line is subject to scrutiny, including operations and maintenance. The temptation to forego or delay preventive maintenance may be overwhelming. This is seldom a wise decision in the long run according to the Federal Transit Association (FTA).
The FTA-sponsored Transit Cooperative Research Program (TCRP) concluded that performing preventive maintenance helps ensure that buses run on time, protects taxpayers’ investments, promotes passenger satisfaction and public safety, and enables buses to reach their expected service life.
Mileage-based intervals not ideal for HVAC systems
Operators usually perform preventive maintenance inspections and routine service on their buses based on the number of miles driven. For example, many transit companies change engine oil, lubricate the chassis and go through an inspection checklist at 6,000-mile intervals, adding other maintenance tasks at multiples of 6,000 miles. Thermo King recommends that preventive maintenance inspections and services on HVAC systems at scheduled intervals. The recommended schedule to aligns time intervals with typical bus mileage, recognizing the fact that the HVAC system works just as hard — maybe harder —while the bus is idling in traffic than when it is in motion. The company uses the common industry “A-B-C” approach to maintenance, recommending that basic or “A” inspections and tasks such as changing return air filters, checking compressor oil color and level and checking condenser coils for debris be performed monthly. “B” inspections and tasks such as checking refrigerant levels in the spring, testing heaters in the fall, and inspecting and lubricating the clutch should be performed seasonally. “C” level inspections and tasks such as testing the compressor oil for acidity should be performed once a year. Operators may want to consider modifying the recommended preventive maintenance schedule to reflect their unique operations. For example, they may need to change air return filters more frequently in regions known for having high levels of dust or other particulates in the air. Units tend to work harder in warmer climates, making it a good idea to inspect compressors more frequently.
Regular HVAC maintenance improves reliability The FTA-sponsored Transit Cooperative Research Program (TCRP) study Preventive Maintenance Intervals for Transit Buses, published in 2010, concluded that performing preventive maintenance helps ensure that buses run on time, protects taxpayers’ investments, promotes passenger satisfaction and public safety, and enables buses to reach their expected service life. Thermo King, Minneapolis, MN, a brand of Ingersoll Rand, has reached a similar conclusion following years of research and experience. As a global leader in transport refrigeration and Thermo King strongly encourages transit maintenance teams to adopt a robust preventive maintenance program for their bus climate control systems and to service their HVAC systems at regular intervals.
5454 October 2012 BUSRideMaintenance
During this time of year, warm temperatures are over for most of the country, which makes this an ideal time for bus maintenance professionals to think about preparing their fleets’ HVAC systems for the winter ahead. It is also a good time for maintenance managers to review and update their maintenance policies, processes and checklists to make sure that they reflect the changing needs of the organization. There is no substitute for a well-planned, well-executed and proactive HVAC system preventive maintenance strategy to reduce operating costs, improve system reliability and provide passengers with a safe and comfortable ride. BRM ___________________________________________________ Steve Johnson serves with Thermo King, Minneapolis, MN, as product manager responsible for HVAC marketing and product management for United States coach and transit buses.
BUSRide October 2012