Air conditioning systems have different temperature requirements depending on where they are used, says David Barden, technical support manager, Power Probe Tek (www.powerprobetek.com), a manufacturer of diagnostic equipment for the automotive industry. In-cab AC systems are designed to keep the driver and passengers at a cool, comfortable temperature. AC systems for refrigerated boxes and trailers typically require much lower temperatures, close to or even below freezing temperatures to protect their valuable cargo.
When diagnosing a refrigeration system’s performance, one of the first steps is to monitor the actual temperature of the air coming from the cooling unit’s evaporator – the outlet temperature, Barden explains. Although the actual discharge temperature is what is normally measured, it is more important to know the net temperature drop created. How much did it actually cool the air?
Another step is to determine the temperature of the air going into the AC system before cooling, he adds. This is known as ambient air temperature.
Comparing the ambient air temperature to the evaporator outlet temperature gives a true measure of the system’s efficiency, he says.
Flow Problems
Checking an AC system’s cooling efficiency with simple temperature checks can alert a technician to possible airflow problems or even indicate if the refrigerant charge level is too low or high, Barden says. Regularly checking cooling system temperatures as part of a preventive maintenance program could potentially spot system inefficiencies and possible loss of refrigerant before the issue causes a larger problem, like a total shutdown of the AC system.
Having a tool that could show multiple temperatures at multiple locations could save time and effort when servicing AC systems.
By way of example, Barden says Power Probe Tek’s recently introduced TEMPKIT easily monitors air temperatures at multiple locations. It uses a receiver/base unit for measuring ambient air temperature and a remote temperature sensor that wirelessly transmits secondary temperature readings back to the base unit up to 16’ away.
This, he says, allows readings to be quickly and easily analyzed.
