News
Putting the Chill in Air Conditioning Maintenance, Parts Procurement
WRITTEN BY JIM ROMEO Trans-Air’s Rick Lehnert outlined
A technician checks the air conditioning manifold pressure to ensure the compressor is functioning properly.
the following components as points of focus in maintaining the system for an optimal lifecycle: Expansion valves: Not all
are created equal. Ensure that those you order as replacement parts are compatible with your system and configuration. Many expansion valves may not have the same internal specifications, causing compressor liquid flood- ing and proper refrigerant flow adjustment to varying conditions. Lubrication: Lubricant is specif-
S
outh Carolina legislators recently overrode a governor’s veto on a bill that would allow lottery funds to be used for purchasing new and modern school buses to replace the state’s deteriorating and aged fleet; many do not have air conditioning. It’s a general but growing concern of many parents.
In Conroe, Texas last year, some parents kept their kids home because of hot and overcrowded
buses. Two years earlier, at the IDEA Public Schools near San Antonio, Texas, parents expressed great concern as their children embarked on buses in the Rio Grande Valley, where summer temperatures reach triple digits. And in 2016, a student in Huntsville, Alabama purportedly suffered from mild heat stroke after riding a bus with temperatures nearing 100 degrees—without air conditioning on the bus. Many school district buses operate without the climate control technology; however, more and
more fleets are purchasing buses with air conditioning. A couple of years ago, Texas changed its state specifications to allow school districts to add it. Costs aside, a tacit concern was supporting and maintaining the parts and equipment. “Te A/C units we have are on our Type A buses and are installed as aftermarket systems,” said
Lawrence Hannan, operations director at Unified School District 320 in Wamego, Kansas. “We have one right now that is not working properly. We took this to two local Chevrolet dealerships, spent about $3,000, and (we) are still unable to get them fixed.” He added that the dealers’ explanations were that they don’t work on aftermarket parts, this
after already expending resources attempting to fix the system. Despite this, Hannan said air conditioning remains low on the district’s list of concerns. “We only
have a couple of weeks in the beginning of the school year and at the end of the school year where it becomes really hot. Tus, we have chosen to not install AC on our big buses,” he told STN. “We transport our more fragile students in these Type A buses, and a few of them are heat sensitive.”
MAINTENANCE MANAGEMENT & PART SUPPORTABILITY While air conditioning systems provide comfort to those on the bus, they are expensive
to replace. Tis fact makes smart maintenance practices such as cleaning evaporator filters and condenser coils crucial to their reliability and operation, said Rick Lehnert, president at
16 School Transportation News • MARCH 2018
ic for compressors and demands different quality levels—single or double capped, with specific vis- cosity and other parameters. Make sure mechanics are using the proper lubricant that matches the need of the part or component. Drying media: Filter dryers
that separate and remove acid particles from the system can look the same. Inferior quality can degrade and contami- nate the system, resulting in a clogging system that can cause compressor failure, and clog the condenser, requiring component replacement. Lehnert emphasized that failure to perform routine maintenance can be costly. A $25 component can cause $3,000 or more in repairs. Replacement: Ensure they are changed out at proper intervals. Drive belts for AC compressors have specific specs for reliable operation and belt life. Change out should be scheduled per the manufacturer’s specifications.
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