The equipment in this month’s troubleshooting situation is a split system that has only been in service for two years, but there is a lot of history — several service calls since the equipment was installed, and an ongoing complaint that the system just doesn’t keep the ranch-style home comfortable. The customer’s description of the problem is that house often feels “sticky.”
Several technicians have reported that they checked the refrigerant charge and found it to be normal. One technician reported adjusting the OBD supply registers in an attempt to achieve a better balance of airflow throughout the three bedrooms, the living room, the dining room, and the kitchen. Another technician replaced the PSC indoor blower motor with an exact OEM replacement motor and capacitor. None of the previous service calls solved the problem.
Considering the previous work performed, you decide to perform a series of tests involving dry bulb and wet bulb checks of the return and supply air of the equipment (see Figure 1), and once your temperature tests are recorded, you perform psychrometric calculations that show a significant specific humidity change in the return duct system.
Your troubleshooting question: What is the next step you need to take in servicing this equipment?
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Publication date: 4/8/2019