Service manual

10
8. A TYPICAL COOLING CYCLE OF THE HEAT PUMP
Begins with a call from the wall thermostat for High or Low fan
(customer choice).
Indoor fan starts on the selected speed.
Within a few seconds the thermostat will call for cooling.
Compressor 1 starts.
Outdoor fan starts 2 seconds later (Low Speed).
1 minute later the thermostat calls for second stage cool
(subject to 2 degree temp. differential).
Compressor 2 starts, the outdoor fan goes off (subject to
available 115 volt power supply).
Outdoor fan starts again 2 seconds later (High Speed).
Both systems operate to satisfy the thermostat.
Both compressors shut off at setpoint temperature.
When the thermostat calls for cooling again it will start by
calling for stage one only.
If the heat pump is unable to keep up with the load, stage 2 will
start again when the indoor temperature is 2 degrees above the
setpoint.
9. A TYPICAL HEATING CYCLE OF THE HEAT PUMP
(Electric Heat Mode)
Begins with a call from the wall thermostat for Electric Heat.
Indoor fan starts on High Speed.
Both reversing valves switch to heat mode.
Compressor 1 starts.
Outdoor fan starts 2 seconds later (Low Speed).
30 seconds later the Heat Pump circuit board will energize the
Compressor Relay #2.
Compressor 2 starts, the outdoor fan goes off (subject to
available 115 volt power supply).
Outdoor fan starts again 2 seconds later (High Speed).
Both systems operate to satisfy the thermostat.
Both compressors shut off at set point temperature.
If the Heat Pump is unable to maintain the coach temperature,
the thermostat will automatically cycle the furnace on. The
new True-Air Thermostats (Electric Heat Mode) will call for
second stage (Furnace) heating operation anytime the
temperature inside the coach is more than 5 degrees cooler
than the customers chosen setpoint temperature. It is entirely
possible the furnace and the heat pump may both operate at
the same time to satisfy the thermostat.