Dometic FreshJet 3 Series Installation And Operation Manual page 22

Operation
When the heat pump is active:
• The reversing valve output turns on and the system
cycles the compressor on and off based on the
measured room temperature and the setpoint
temperature.
• The compressor cycles on when the room
temperature sensor measures the room temperature
at equal to or below the setpoint temperature minus
1 °F (0.5 °C).
• The compressor cycles off when the room
temperature sensor measures the room temperature
at equal to or above the setpoint temperature plus
1 °F (0.5 °C).
For example, if the setpoint is 72 °F (22 °C), the
compressor cycles on when the temperature drops
to (or below) 71 °F (22 °C) and cycles off when the
temperature rises to (or above) 73 °F (23 °C).
In Auxiliary Heat mode, four fan speed selections are
available: Low, High, Turbo, and Auto.
I With the fan speed set to Low, High, or Turbo, the
fan runs continuously in the selected speed.
I With the fan speed set to Auto, the fan cycles on
when the compressor is on and cycles off when the
compressor is off. A 15 second fan on delay will be
active.
When the furnace is running, the fan is off in Auto
I
mode.
• Auto: if the fan speed selected is Auto, the Fan speed
changes automatically based on the temperature
differential between the room temperature and the
setpoint temperature.
• Turbo: the fan operates at Turbo speed when the
room temperature is below the setpoint temperature
by more than 8 °F ±0.5 °F (5 °C ±0.3 °C).
• High: the fan operates at High speed when the room
temperature is below the setpoint temperature by
5 °F to 7 °F ±0.5 °F (3 °C to 4 °C ±0.3 °C).
• Low: the fan operates at Low speed when the room
temperature is below the setpoint temperature by
less than 4 °F ±0.5 °F (2 °C ±0.3 °C). The 15 second
fan on delay will be active.
22
Rooftop Air Conditioner (Air Distribution Box, Electronic Controls)
During heat pump operation, the defrost cycle may
occur. The defrost cycle occurs when the measured
temperature of the outdoor ambient sensor is between
30 °F and 42 °F (–1 °C and 6 °C).
• The LED display alternates between HP and DF every
ten seconds to indicate that the defrost cycle is active.
In the defrost cycle, the accumulated compressor
run time of the heat pump is monitored. When the
accumulated compressor run time equals 25 minutes,
the fan turns off and the reversing valve de-energizes.
The compressor continues to run for 4.5 minutes and
then the reversing valve will be energized. After a 30
second delay to allow the indoor coils to heat up, the
fan turns on.
• The defrost cycle continues until the measured
temperature of the outdoor ambient sensor drops
to (or below) 30 °F (–1 °C) or rises to (or above)
42 °F (6 °C).
• The LED display alternates between HP and DF in one
second intervals to indicate that the defrost cycle is
active.
During heat pump operation, a low ambient heat pump
lock out may occur. Since heat pumps lose efficiency
at low outside ambient temperatures, the heat pump
shuts down if the outside temperature falls below
30 °F (–1 °C). The reversing valve de-energizes when
the heat pump is in the low ambient heat pump lock out
condition. If a furnace is equipped, the system will switch
over to the furnace.
• The LED display alternates between HP and LO in one
second intervals to indicate the outdoor temperature
is 29 °F (–2 °C) or lower.
I The reversing valve energizes continuously when
the heat pump is active, except when it cycles off
during a defrost cycle.
10 .3 .9 Selecting Turbo mode
The Turbo mode provides maximum cooling for
rapid pull-down and/or spot cooling when room
temperatures exceed the setpoint.
1. Press and release the Turbo Mode icon.
All unselected icons illuminate at 50% brightness.
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