From: jeffrey E. <[email protected]> Sent: Tuesday, December 1 2015 8:47 PM To: Larry Visoski Subject: Re: Fun so if the voltage is jumping around is the precooler=valve opening and closing widly. wrote: From Pete Sent from my iPhone Begi= forwarded message: From:</=> Pete Rawson Date: December 1 2015 a= To: Larry Visosk Subject: RE: Fu= Hi La=ry, The answers to the questions from JE =nd you are; The dorsal allows ram air to =ormally go through the left and right heat exchangers. The= are part of the air cycle machines, nothing to do with the precoolers. There are no components, the only change in flow is speed of =he aircraft. It also allows ram air to enter the cabin whe= "Ram" is selected- part of the emergency pressurization system.=/span> The air cycle machines "Packs" then work the tem=erature for the cabin. The overboard air =rom the pylon- That is the fan air that goes through the p=ecooler valve, and across the pylon radiator. The panel re=dings mean- Low voltage, should also have low pressure ind=cation- That allows the precooler valve to open- Air flows=across the pylon radiator and cools the input air to the temp system. High voltage, should also have high pressure- =hat causes the precooler to close- No air across the pylon=radiator. Each side is separate, both in =ontrol and function. See you tomorrow-</=pan> EFTA_R1_01595849 EFTA02479987