Trane Thermo King Magnum Plus Operator's Manual page 30

Dehumidification:
When the Dehumidify
mode is set to On, the supply air temperature
must be In-range to energize the electric
heaters.
• When the humidity is 2 percent or more
above humidity setpoint, the controller
(energizes) the heaters.
5 Controller energizes electric heaters for heat,
defrost and dehumidification:
Heat mode (compressor off):
supply air temperature is too low, heaters pulse
on and off on a 60 second duty cycle.
Defrost mode:
Heaters are on until
evaporator coil temperature increases to
terminate defrost.
If
OPERATING THEORY
27