In this troubleshooting situation, the equipment is a gas pack that has been in service for 18 months. The customer’s complaint is that the unit is running constantly and isn’t keeping them comfortable in the same way it did during the previous summer.

After completing your initial observation of the situation, confirming normal indoor airflow and a higher-than-normal temperature in the building, you also observe that the condenser fan motor is operating normally and that the outdoor coil is clean. When you check the LED status of the equipment, you note that along with the green power indicator, a yellow alert status LED is present, flashing once, then pausing and repeating.

Upon consulting the manufacturer’s troubleshooting information that lists the possibilities for the observed fault code, you confirm that the ambient temperature is 95°F and check the refrigeration system pressures. Using the manufacturer-specific chart available for this R-410A system, you place an “X” at the point on the chart where the suction and liquid pressures cross (see Figure 1).

Your troubleshooting question: What is the underlying cause for the poor performance of this unit?

Compare your answer with ours here.

Publication date: 5/13/2019

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