AIRCRAFT
Heating and Ventilation
DA 42 NG AMM
Page 4
15 Mar 2018
21-50-00
Doc # 7.02.15
Rev. 4
3. Operation
If electrical power is provided to the RACC system, the blue LED on the control panel flashes.
The control panel of the RACC system on the LH sidewall allows the crew to control the fan speed and
the cabin temperature. A two digit display shows the preset cabin air temperature in °F. A push-button
is used to set the RACC system to ON (if the RACC system is already running, the display is
illuminated if the push-button is pressed) and set to OFF (if pressed and held for approximately one
second).
During power-up the software version of the control panel is displayed.
The central unit is located aft of the baggage compartment. The RACC controller is located on top of
the central unit and controls the refrigerant circuit valves and the compressor with respect to the
control panel settings. With the control panel set to ON and a temperature preset lower than the
current cabin air temperature, the refrigerant cooling circuit is activated. An electrically powered
compressor takes the low-pressure low-temperature refrigerant gas and compresses it to a high-
temperature gas. A pressure switch on the compressor assembly regulates the compressor discharge
pressure. The hot refrigerant gas is cooled down in the condenser and condenses to a high pressure
liquid. An axial condenser fan forces outside air through the condenser coils and vents the thus heated
air overboard. The filter / drier / collector bottle removes moisture from the refrigerant and stores the
refrigerant. The expansion valve controls the amount of refrigerant liquid flowing to the evaporator. The
refrigerant boils in the evaporator and turns back into a low-pressure low-temperature gas while
cooling the coils of the evaporator. Two radial cabin fans force cabin air through the cooling coils and
thus remove heat from the cabin air. The cool cabin air cannot hold the moisture and water
condensates on the evaporator cooling coils. The condensate is collected under the evaporator and
is drained overboard. The refrigerant gas returns to the compressor.
A cooling fan vents air through the RH air outlet on top of the fuselage and ensures ventilation of the
rear fuselage.
Summary of Contents for DA 42 NG
Page 933: ...AIRCRAFT DA 42 NG AMM Fuel Doc 7 02 15 Rev 4 28 TITLE Page 1 15 Mar 2018 CHAPTER 28 FUEL ...
Page 1459: ...AIRCRAFT DA 42 NG AMM Lights Doc 7 02 15 Rev 4 33 TITLE Page 1 15 Mar 2018 CHAPTER 33 LIGHTS ...
Page 1711: ...AIRCRAFT DA 42 NG AMM Doors Doc 7 02 15 Rev 4 52 TITLE Page 1 15 Mar 2018 CHAPTER 52 DOORS ...
Page 1853: ...AIRCRAFT DA 42 NG AMM Wings Doc 7 02 15 Rev 4 57 TITLE Page 1 15 Mar 2018 CHAPTER 57 WINGS ...
Page 2071: ...AIRCRAFT DA 42 NG AMM Engine Doc 7 02 15 Rev 4 72 TITLE Page 1 15 Mar 2018 CHAPTER 72 ENGINE ...
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