Page 36 - Climate Control News May 2021

Troubleshooting Tips
HVAC diagnostics:
Tips for service agents
AS COMPUTING POWER ESCALATED AND INVERTER TECHNOLOGY KICKED IN, DIAGNOSING AIR CONDITIONING PROBLEMS BECAME A LOT MORE COMPLEX. MECHANICAL ENGINEER STEVEN MANTINE EXPLAINS WHY THE SERVICE MARKET IS CHANGING AND HOW TO DEAL WITH THE HIGH LEVEL OF FRUSTRATION FROM END USERS COMPLAINING IT IS ALL TOO HARD.
IF THESE COMPLAINTS referred to a large complicated HVAC system it would be understandable but I often hear the same complaints time and again for a sim- ple single split unit.
This is usually due to prolonged (and some- times incorrect) diagnostic procedures that lead to a waste of time and money (and frustration for both the end-user and the service agent).
Air conditioners have evolved and that is ex- actly what we need to do when it comes to man- aging service problems. Here are some tips to help ease the pain.
1IT IS NOT A SYSTEM, IT’S AN ECO-SYSTEM. Compare your HVAC system to any other appliance in your building and there are significant differences. For example, a TV is in- stalled and users get the same level of service whether they are in Victoria or in remote Queensland. An air conditioner’s performance is determined by installation and conditions on- site, pipe length, duct work (which affects air- flow), roof space temperature for a ducted unit, and the list goes on. All of these factors must be taken into consideration.
2IT’S A COMPUTER WITH A COMPRESSOR. In the good old days, it was simple – a couple of thermistors, an on/off compres- sor, fan motors and that’s it. If there was higher demand the compressor would kick in, and when you got below the desired set point the compressor would cut out. Today things are different. The compressor is controlled by soft- ware embedded on the PCB. All the thermis- tors, valves, pressure transducers, pressure switches etc. are connected to the PCB. Infor- mation gathered from the system operates ac- cording to the software inside. Many times, the software has protection protocols (algorithms) that prevent the unit from ramping.
The system will go to protection mode several times before it will produce an error code. To learn more about the algorithms users must read the manuals. Unless you have a monitoring tool there is no way to identify the protection protocols.
3USE THE ENGINEERING AND SERVICE MANUALS. To understand the system, we need to be able to understand how it should work. A good example is in heating op- eration. If the ambient temp (outside) is above
HVAC systems today rely on software making them a little more complex when it comes to diagnostics.
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