When you arrive, you note that the outdoor ambient temperature is 80°F, and when you inspect the air-handling system in the attic, you find that the methods employed in the installation have made it extremely difficult to access the “A” coil, but you are able to make the necessary gauge connections (the HP hose for a high pressure reading at the air entering the coil and the LP hose for a low pressure reading at the air leaving the coil) to test the pressure drop across the coil. (See Figure 1.)
After allowing the system to operate for approximately 20 minutes, and noting that there is condensate in the drain, you begin your pressure test and note that the drop is measured at 0.6 in. wg.
Your troubleshooting question: What is the next step you need to take in order to continue your evaluation of this equipment?
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