The indoor cassette type units act as evaporator coils during cooling mode and condenser coils during heating mode. These
units have a built in condensate pump with an associated condensate level switch. The condensate pump is capable of lifting
water out of the indoor unit. If high water lift is needed, the water from the cassette pump should be pumped into a field supplied
condensate pump with high lift power.
Cassette type indoor units can be operated with a wired controller or a remote control.
Power to operate the indoor unit comes from the electrical line voltage terminal block at the outdoor unit. The wiring
includes 4 wires, 1, 2, 3 and ground. Wires 1 and 3 complete the data path. These wires should always be 14 gauge AWG
Stranded type wire. Splices in wires 1 or 3 may cause communication errors.
The indoor unit features a multi speed blower motor that will change speed to match the capacity demand from the
outdoor unit. Separate motors located in the indoor unit control the operation of the motorized louvers. All of the louver
motors are controlled via commands received from the remote control. The blower motor is controlled by both the remote
control and by commands from the outdoor unit ECU.
The indoor unit has a display that communicates system mode. The indoor unit does not display temperatures or
diagnostic codes. When a wired controller is used, this information is displayed on the wired controller. It is recommended
to use a wired controller with the cassette unit.
When servicing a diagnostic error, ALWAYS refer to the outdoor unit code to make diagnostic decisions.
COMPACT CASSETTE TECHNICAL OVERVIEW