Labels:text | map | screenshot OCR: Airbus A320 bleed air system sense-line connections.Es T he A320's bleed air system is However, at a higher engine setting supplied with air by the (i.e. when the air is bled from the IP Fan air valve Precooler PRV CTL (TLT) solenoid FAV CTL thermostat (TCT) TCT sense line intermediate pressure check valve (IPCV) 7110HM1 (2) and the stage), a non return valve which is part 1 OHA1 (2) 7170HM 1(2) HP bleed valve (HPV) of the PRV internal mechanism is closed and the PRV command 4000HA1(2). The HPV is a spring- Overpressure Temperature pressure signal is provided directly with valve sensor loaded-closed valve which regulates air from the IP stage. 5HA1(2). 6HA1(2) a downstream pressure of 36 +/- 4 A third sense line connects the TLT pounds per square inch gauge (psig) Reverse flow and the transfer pressure transducer sense line and closes when upstream pressure PRV/TLT exceeds 100 psig. 7HA1(2) upstream of the PRV. The reason for this is to ensure the reverse sense line Transfer pressure The pressure regulating valve (PRV) flow protection of the system by transducer 7HA1(2) 4001HA1 (2) is a spring-loaded-closed reading the differential between Union valve and regulates pneumatically at pressure upstream of the PRV and 44 psig +/- 4 psig. The regulated downstream of the precooler. When pressure is sensed by the PRV through this pressure differential is less that Flex lines Regulated pressure the downstream filter. Fluctuations of a 0.145 psi the TLT vents the PRV-TLT sense transducer 8HA1 (2) maximum of 4 psig around the line to ambient and the PRV closes. This regulated value are normal. The function is inhibited when the pressure regulated pressure is monitored by the sensed by the TLT (downstream of the Fan air valve Bleed pressure 9HA1(2) Regulated pressure sense line F O pressure transducer 8HA1(2). precooler) is less than 9.43 psi. This regulating additional The PRV is controlled closed when allows PRV opening after engine start valve 4001HA1(2) Union reference & bracket consult Bleed the PRV control solenoid (TLT) 10HA 1(2) when the bleed air flow through the PRV System Operation is energized. is not stabilized. description The fan air valve (FAV) 9HA1(2) is a PRV HPV Troubleshooting on: Two sense lines are connected to 6 ECAM wamning AIR ENG 1(2) the PRV which provide the spring-loaded-closed valve. It opens Upstream sense line BLEED FAULT opening/closure command signal with muscle pressure provided from the pressure 6 ECAM warning AIR ENG 1(2) temperature control thermostat (TCT) sense line High pressure HP VALVE FAULT from the TLT to the PRV and the HPV. regulating valve 6 ECAM warning AIR ENG 1(2) 4000HA1(2) ABNORM PRESS 6 PRV-TLT: This sense line is vented to 7170HM(2) through a sense line. The 6 ECAM warning AIR ENG 1(2) ambient when the TLT is energized. muscle pressure from downstream of IP check BLEED NOT CLOSED valve 6 Pressure fluctuations The PRV then closes. the precooler flows through a filter in Reference: Brian Mushich, A320fleet supervisor 6 PRV-HPV: This sense line their ensures HPV closure when the PRV is controlled closed i.e. venting to ambient PRV- "See TLT and PRV-HPV enlargement above right.
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