Mitsubishi Electric PAA-A18AA1 Manuel D'installation page 65

13. Float switch
IMPORTANT
Float switch is required for all PAA unit installation orientations.
In order to protect the gas furnace from corrosion, Mitsubishi Electric US, Inc. requires
installing a float switch. If the float switch is not installed, Mitsubishi Electric US, Inc. is not
responsible for any damage to the furnace.
Inspect the float switch for damage. If damaged, obtain a replacement before continuing
the installation.
NOTE
The float switch must be installed for proper system operation. An error code will result if
the switch is not installed.
The float switch, also called the AC safety switch, is an electronic water sensor for your HVAC system. It
gives the AC system the ability to detect water backing up into the drain pan, possibly indicating a clogged
drain. The float switch will shut the system off if the water level reaches a certain point.
The float switch is installed in the secondary drain line of the air conditioner, and if water begins to
accumulate in the drain line, the ball inside the switch will begin to float. When the ball floats to the top of
the drain line, the switch will transmit a signal to the PAA unit to turn off, preventing an overflow.
Specifications are subject to change without notice.
PAA-A18, 24, 30, 36, 42AA1/BA1/CA1
65 © 2022 Mitsubishi Electric US, Inc.