Arkansas HVACR NewsMagazine November 2021

HVACR NewsMagazine November 2021

Tech News

can prohibit optimum operation for the air side and refrigerant side. If there’s anything wrong with the airflow/ductwork, it can prohibit proper operation for the refrigerant side, and so on. Checking each area of the system in this order ensures that nothing gets missed during the commissioning process. It also keeps a technician from having to recheck the charge that is no longer the same because the airflow wasn’t set properly. In truth, most of these areas of the system will be checked simultaneously, especially if you are using measureQuick. But if there were a best- practice sequence of commissioning, this would be it. The electrical side of a system is one of the easiest to check, and it’s also one of the easiest to overlook. Use your eyes first! Visually inspect everything. With the power off to the appliance, give a good tug on all the electrical connections, including contactors, relays, wire nuts, etc., to ensure that the connections are solid and nothing is loose. Use your ears to listen for any abnormal buzzing/humming from transformers, relays, and other components. Confirm that the wire size is appropriate for the application based on the equipment ratings, including any heater kits installed. Make sure the applied voltage matches the way the motors and transformers are wired up. Keep a lookout for any discoloration or char marks on the wires, and pay very close attention to any splices in the thermostat wire. Electrical

manuals (RTFM!) to make sure the wiring is correct and that any field-applied settings are made correctly. You’ll want to check the defrost board wiring and even capacitor wiring. Many technicians keep multi-speed blower motors set to the factory setting, but that may need to be changed, depending on your market and the specific application of the system. Amperage from the compressor and fan motors can also tell you something about how the system is operating. The current draw will change by the load, but it’s not hard to tell when a compressor is over or under-amping under the given conditions. If you are using

measureQuick, you will even be able to check power factors and calculate EER and estimated SEER from your electrical readings

The next step would be to study the wiring diagrams and the installation