A320 pneumatic question
 

Dear all

I have a question related to A320 pneumatics. Kindly help me out

FCOM says +/- 36 psi is obtained from the HP stage of the high pressure compressor when IP stage pressure is insufficient

I would like to know when IP stage is supplying ( NO HP stage involved) what is the pressure obtained ? is it also +/- 36 psi just like when HP stage is supplying ?
IP stage pressure is not mentioned in the FCOM

However Bleed valve PRSOV maintains a delivery pressure of +/- 45 psi (CEO ) , Does this mean IP stage when open will supply as much pressure as it can (even more than 45 psi) and bleed PRSOV will then regulate it to +/- 45 psi ,
And since HP valve is open at low engine power , the pressure coming out of HP vale is generally low , so +/- 36 psi is the pressure obtained more pressure is not possible

please correct me if my understanding is correct


I thank you and I am grateful

Regards
Overhead

Correct. At high engine speed the IP will provide unregulated air pressure which is then regulated by the bleed valve to 45 +/- 5 PSI. At low engine speed, the IP pressure is insufficient, and the HP stage provides 36 +/- 4 PSI. When the IP stage is capable of providing sufficient pressure, the HP valve closes pneumatically as a result of excessive high upstream pressure (ie. If there is sufficient IP pressure, there is going to be excessive HP pressure).

Thank you so much JH870. great explanation