EFFECTIVITY:
21-40-00 PAGE3
PIPER AIRCRAFT
PA-42-720(AdvancedTrainer)
MAINTENANCEMANUAL
A. Heating and Cooling (continued)
2. ComponentDetailedDescriptions(continued)
(k)
Water Separator Assembly This assembly consists of a coalescer,watercollector,and drain. The drainconsistsof a line, routedto the water aspiratoron the air inlet side of the refrigeration unit,aheadof the heat exchangers.A small portionof bleed air is extractedfrom the heat exchangerand is routed throughthe aspirator, causinghigh velocity air flow through the aspirator andcreating a vacuumon the drain line which removesanywaterfrom the water separator collector.This moistureis sprayed into the ambientair ahead of the heatexchanger to provide additional coolingcapacity.
(I)
DuctTemperatureSensor This sensor, locatedin the cabinair supply duct downstream of the water separator,senses cabin air temperature.Thisunit, capable of monitoring temperaturesbetween+30°F to 200°F, supplies sensor data to the cabin temperaturesensorand controller.
(m)CabinTemperature Sensor and Controller Thisunitworks in conjunctionwith the duct temperature sensor and cabintemperatureselector to control the hot air bypassvalve and maintainsthe desired cabin temperature.It is centrally mountedin the aircraft cabin. The controller range of operationis +30°F to 160°F. The ECSmust maintain the average cabin and cockpittemperaturesof 75°F for cooling and 80°Ffor heating. Duringgroundoperation,the system must maintainthe cabin at an average temperatureof 75°F or less. During a hot day, the system mustpull the cabin temperature below 80°F in 20 minutes or less from the time the system is turned on. The cabin temperature control automatically maintainsthe temperatureat the sensorwithin ± 3°F of the selected setting.
(n) CoolingFan Thecooling fan is energized by the landinggear squat switch only when the aircraftis on the ground. It provides ram air cooling for both the primary and secondary heat exchangers througha 28-volt vane axial fan.
3. Removal of Pressure Regulator and Shutoff Valve
(a)
Removewaterseparator according to instructions in this chapter.
(b)
Disengagebleed air circuit breaker.
(c)
Disconnectpressure regulator sensingtubefrompressureregulating and shutoffvalve.
(d)
Disconnectelectrical plug from pressure regulatingand shutoff valve.
(e)
Removecouplings securing pressureregulatorand shutoff valveassemblyin position.
(f)
Removepressureregulatorand shutoff valvefrom airplane.
4. Installationof Pressure Regulator and ShutoffValve
(a)
Ensurepressureregulatorandshutoff valve are in position and securedwith couplings. Torque couplingsto 35 -45 inch-pounds.
(b)
Connectpressure regulator sensingtubeto pressureregulating and shutoffvalve.
(c)
Connectelectricalplugto pressure regulating and shutoffvalve.
(d)
Engagebleedair circuit breaker.
(e)
Installwaterseparatoraccordingto instructions in this chapter.
5. Removal of Hot Air Bypass Valve
(a)
Disengagecabintemperaturecircuitbreaker.
(b)
Disconnectelectricalplug from bypassvalve.
(c)
Removecouplings securing bypassvalvetoduct flange.
(d)Removebypassvalve and seals.
EFFECTIVITY: 040-999
Jan 10/9021-40-00
PIPERAIRCRAFT
PA-42-720(Advanced Trainer)
MAINTENANCEMANUAL
A. Heatingand Cooling(continued)
6. Installationof HotAir BypassValve
(a)
Securebypassvalveand newsealsto ductflangeusingpreviouslyremovedcouplings. Torquecouplingsto 35 ± 3.5 inch-pounds.
(b)
Connectelectricalconnectorto bypassvalve.
(c)
Engagecabintemperaturecircuitbreaker.
7. Removalof BleedAir SupplyOverpressureSwitch
(a)
Gainaccessto overpressureswitch. (Figure 401)
(b)
Disconnectelectricalconnectorfromswitch.
(c)
Cutsafetywire and unscrewswitchfromreceptacle.
(d)
Removeswitchand O-ring.
8. Installationof BleedAir SupplyOverpressureSwitch
(a)
InstallnewswitchandO-ringintoreceptacle.
NOTE: EnsureproperhightemperatureO-ringis usedby referringto PartsCatalog.
(b)
Secureswitchwith safetywire.
(c)
Reconnectelectricalconnectorswitch.
9. Removalof CompressorDischargeOvertemperatureSensingSwitch
(a)
Gainaccessto overtemperatureswitch. (Figure 401)
NOTE: Notelocationof eachwireto facilitatereinstallation.
(b)
Disconnectelectricalleadsfrom switch.
(c)
Loosennut andunscrewswitchfromreceptacle.
(d)
Removeswitchand O-ring.
10. Installationof CompressorDischargeOvertemperatureSensingSwitch
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本文链接地址：夏延飞机维护手册 Cheyenne IIIA PA-42-720 AMM 1(67)
