Arkansas HVACR NewsMagazine March 2021

S tate, National, Chapter News Tech News

function a little differently. Let’s dive into what’s different about them. Inverter-driven compressors : Right from the start, these systems use an inverter-driven compressor to control capacity (some have an AC compressor, others have a DC compressor; refer to the manufacturer’s literature or data plate). A circuit board has two possible functions. It may rectify incoming power to DC before inverting it back to AC to drive the compressor, or it may merely control the DC output to produce a variable speed effect. Compressor speeds are a function of meeting either the target evaporator temperature (cooling mode) or the target condensing temperature (heating mode). TE (target evaporator) and TC (target condenser) calculation come from how far off setpoint the return air temperature, room controller temperature, or remote controller temperature is. The further off the setpoint is, the faster the compressor will run (the lower the TE or higher the TC). Run speed is published typically in RPS (revolutions per second). The typical range on most units is 25-120 RPS. EEVs : Electronic expansion valves are electronically controlled devices that meter the flow of refrigerant through the system. One-to-one units will have one expansion valve, while multi-splits will have one per port. If it’s a four -port unit, there will be four EEVs in the machine. Each EEV controls refrigerant flow to each indoor coil attached. EEVs either

MINI-SPLITS FOR NEW HVAC TECHS

Emi ly Gutowski & Ryan Findley

This article will be geared toward HVAC techs who are new to mini-splits. As the mini-split market continues to grow, technicians face more and more challenges with these systems. The most critical challenges would be insufficient training and the lack of proper tools to work on mini-splits effectively. To start, I advise going to as much manufacturer training as your employer will allow. I will give you some highlights of how mini-splits work, how to troubleshoot them, and what tools you will need to be effective at troubleshooting them. Mini-splits, like their bigger VRF machine cousins, have a lot of mystique that surrounds them. In my opinion, they don’t warrant the mystique. Mini - splits still operate under the same rules of thermodynamics that standard unitary equipment does. They just HOW MINI-SPLITS ARE DIFFERENT