Floreng From United States of America, joined Dec 2009, 10 posts, RR: 0 Posted (3 years 4 months 3 weeks 6 days 18 hours ago) and read 4716 times:
Hi,
I am looking for a schematic of the Honeywell 131-9A or -9B APU lubrication system (that's the APU for the B737NG and some of the A319-A321s). More specifically, I am trying to identify the locations of the oil pressure/oil temperature sensors, and whether all three lube module circuits have such sensors. Thanks a lot for any help and happy holidays!
Tdscanuck From Canada, joined Jan 2006, 12709 posts, RR: 81 Reply 1, posted (3 years 4 months 3 weeks 6 days 11 hours ago) and read 4678 times:
Quoting Floreng (Thread starter): I am looking for a schematic of the Honeywell 131-9A or -9B APU lubrication system (that's the APU for the B737NG and some of the A319-A321s).
737NG SSM 49-94-00 - APU Oil Distribution
Quoting Floreng (Thread starter): More specifically, I am trying to identify the locations of the oil pressure/oil temperature sensors, and whether all three lube module circuits have such sensors.
It does not appear so. The output from all three pumps comes together prior to the pressure regulating valve before it heads to the oil cooler. The temperature sensor is on the oil cooler return and the pressure sensor is on the line from the lube module to the APU.
Floreng From United States of America, joined Dec 2009, 10 posts, RR: 0 Reply 2, posted (3 years 4 months 3 weeks 6 days 10 hours ago) and read 4669 times:
Quoting Tdscanuck (Reply 1): It does not appear so. The output from all three pumps comes together prior to the pressure regulating valve before it heads to the oil cooler. The temperature sensor is on the oil cooler return and the pressure sensor is on the line from the lube module to the APU.
Thanks Tom, what would happen if the third pump on the lube module (the one that draws from the APU power section bearing) is not pumping because of a damaged gerotor while the other two three-module pumps are pumping OK and the overall pressure shows ok - can that affect the lubrication of the APU power section bearing?
Chris
Tdscanuck From Canada, joined Jan 2006, 12709 posts, RR: 81 Reply 3, posted (3 years 4 months 3 weeks 5 days 20 hours ago) and read 4621 times:
Quoting Floreng (Reply 2): Thanks Tom, what would happen if the third pump on the lube module (the one that draws from the APU power section bearing) is not pumping because of a damaged gerotor while the other two three-module pumps are pumping OK and the overall pressure shows ok - can that affect the lubrication of the APU power section bearing?
This is not my area of expertise but, as far as I can tell from the schematic, it shouldn't make much difference. I don't have a great sense for the fidelity of the schematic I've got though.
There appear to be seven distinct pumps within the module...three to scavenge the generator, one to scavenge the turbine, and three pressurizing pumps to feed oil to the APU. The output of the three pressurizing pumps appears to be combined; as long as you've got flow and pressure from two remaining pumps, it looks like everything will get oil.
But I'd talk to an APU mechanic or a Honeywell person for a definitive answer on that one.
Floreng From United States of America, joined Dec 2009, 10 posts, RR: 0 Reply 4, posted (3 years 4 months 3 weeks 5 days 17 hours ago) and read 4602 times:
Quoting Tdscanuck (Reply 3): But I'd talk to an APU mechanic or a Honeywell person for a definitive answer on that one
Thanks, Tom. Please let me know if you find anything else.
Happy holidays!
HAWK21M From India, joined Jan 2001, 31201 posts, RR: 58 Reply 5, posted (3 years 4 months 3 weeks 5 days 8 hours ago) and read 4537 times:
Quoting Floreng (Reply 2): Thanks Tom, what would happen if the third pump on the lube module (the one that draws from the APU power section bearing) is not pumping because of a damaged gerotor while the other two three-module pumps are pumping OK and the overall pressure shows ok - can that affect the lubrication of the APU power section bearing?
I suppose Fault Isolation manual will suggest replacing the Oil pump unit assy.The overhaul strip report thereafter if requested will reveal the internal fault.
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