Tips for Technicians

The first step in any HVACR troubleshooting process, when a system seems to have trouble cooling or heating a space, is to always ensure the system is getting power. Start with the distribution board, where the power for the unit is divided into subsidiary circuits. From there, trace the power into the isolator, and then check if power is being supplied out of the isolator to the unit. If there’s no power coming out of the isolator, you’ll need to check for blown fuses or breakers. This simple step can save you a lot of time by confirming that the power is not the issue.

Once you’ve confirmed power is reaching the unit, it’s time to move on and inspect the unit itself. First, check the cables. Inspect all the wiring to ensure there’s no damage or loose connections. A broken or frayed cable can easily be the cause of a system failure, so make sure all connections are secure.

Now, start working your way through the components of the HVACR system, one by one. The next step could involve refrigerant issues, which can be tricky and often misinterpreted. Refrigerant problems may not always be immediately obvious, and symptoms can range from reduced cooling or heating efficiency to complete system failure. So, when you start suspecting an issue with the refrigerant, you could check for a few things to figure out what is going on in the system.

First, switch the unit on and set it to cooling mode. Let the unit run for a few minutes before making observations: this gives the system time to run for a little and for any refrigerant flow issues to become more apparent. Pay close attention to the compressor during your observation time. Why? Well, the compressor is responsible for circulating refrigerant around the system, so a compressor that’s struggling or not running at all can be an indication that the refrigerant charge or system pressure isn’t right.

Next, the temperatures around the pipework should be tested. The pipes, or lines, can tell you a lot about how the refrigerant is circulating in the system. If the suction line measures warm or the discharge line’s measurement is colder than expected, this suggests that refrigerant is either not circulating properly or that there is a restriction somewhere in the system, such as a blocked expansion valve, solenoid, or filter. An abnormal temperature in either one of these lines can indicate low refrigerant levels, or it may point to a leak in the system that is preventing the refrigerant from reaching its intended pressure.

After checking the temperatures, it’s important to check the refrigerant pressures as well. Pressure readings can give you critical insight into the health of the system. Low pressures might indicate a refrigerant leak or undercharging, while high pressures could suggest overcharging or a restriction in the refrigerant flow. By monitoring both suction and discharge pressures, you can get a clearer picture of the system’s performance and potentially identify where the issue lies.

After checking the temperatures and pressures around the lines to make sure the refrigerant is flowing around the system, you should check if the solenoid and expansion valves are working correctly. The solenoid valve is an on/off switch for refrigerant flow, while the expansion valve is a precise control mechanism that regulates the refrigerant’s flow and pressure as it enters the evaporator coil. Either one of the valves not working properly could cause issues for the entire HVACR system.

At this point in your troubleshooting process, it would be a good idea to check the refrigerant charge of the system. This ensures the system isn’t undercharged or overcharged, which could be the root cause of the cooling issues your customer is facing. When your refrigerant charge seems to be off, your next step could be to check for refrigerant leaks. Even the smallest leaks can lead to underperformance of the system over time.