Bryant PACKAGED HEAT PUMP 548J - Manual (Page 67)

67
At the end of the defrost cycle, the electric heaters (if
installed) will be deenergized; the reversing valves switch
and the outdoor-fan motor will be energized. The unit will
now operate in the Heating mode.
If the space thermostat is satisfied during a defrost cycle,
the unit will continue in the Defrost mode until the time or
temperature constraints are satisfied.
Automatic changeover
When the system selection switch is set at AUTO.
position, unit automatically changes from heating
operation to cooling operation when the temperature of
the conditioned space rises to the cooling level setting.
When the temperature of the conditioned space falls to the
heating level setting, unit automatically changes from
cooling to heating operation (with a 3°F deadband in
between).
Continuous air circulation
Turn unit power on. Set system control at OFF position.
Set fan switch at ON position. The indoor-fan contactor is
energized through the thermostat switch and the indoor
fan runs continuously.
Cycle-LOC™ protection
If unit operation is interrupted by an open high-pressure
switch, low-pressure switch, indoor coil freeze stat, or by
compressor internal line-break device (overcurrent or
overtemperature), and compressor is calling for either
cooling or heating, Cycle-LOC protection device
simultaneously locks out unit and lights a warning light on
the thermostat. Restart the unit by manually turning
thermostat to OFF and then to ON position. If any of the
protective devices opens again, the unit continues to lock
out until corrective action is taken.
NOTE: If the unit fails to operate due to compressor
over-current condition, restart by manually resetting
circuit breakers at the unit. Restart cannot be
accomplished at the room thermostat.
Emergency heat
If compressor is inoperative due to a tripped safety device
(high or low pressure, indoor coil freeze stat, overcurrent,
or overtemperature), the Cycle-LOC device locks out the
compressor and lights a warning light on the room
thermostat. When the switch is on (thermostat is set to the
EM HT position), compressor circuit and outdoor
thermostats are bypassed, and the second stage of
thermostat energizes the indoor blower and the electric
resistance heaters.
548J