Selecting An Installation Site; Basic Operation Of The Paa Unit - Mitsubishi Electric PAAA18AA1 Installation Manual

PAA-A18, 24, 30, 36, 42AA1/BA1/CA1

7. Selecting an installation site

• Avoid installing the PAA unit in locations exposed to outside air.
• Select a location that does not obstruct the airflow in and out of the unit.
• Avoid installing the PAA unit and control box in locations that will expose it to steam or vapor.
• Avoid installing the control box near locations where combustible gas or oil may leak, settle, or be
generated.
• Avoid installation near machines emitting high-frequency waves (high frequency welders, etc.).
• Avoid installing the PAA unit in locations where the airflow is directed at a fire alarm sensor. (Hot air could
trigger the alarm during operation.)
• Avoid installing the PAA unit in places where acidic solutions are frequently used.
• Avoid installing the PAA unit in places where sulphur-based or other sprays are commonly used.
• When the PAA unit is installed in the horizontal position, ensure that a drain pan is installed under the
entire cabinet.
• Install sufficient thermal insulation to prevent condensation from forming on the outlet and inlet ducts.

7.1. Basic operation of the PAA unit

The PAA unit system combines an A-Coil that is mounted on to a furnace with a PAA control box to control
the system. The system uses the fan of the attached furnace to operate in Cool mode and while running
heat pump in Heat mode. If the system is unable to keep up with the demand for heat, the system switches
to furnace operation.
Specifications are subject to change without notice. 33 © 2022 Mitsubishi Electric US, Inc.