What was found
AIRCRAFT WAS GROUNDED: MULTIPLE LAVATORIES INOPERATIVE, FLIGHT DIVERTED TO BOS. REPLACED 2EA VACUUM CHECK VALVES IAW AMM 38-32-07, 2EA BAROMETRIC SWITCHES IAW AMM 38-32-51-40, AND RELAY K38004 IAW SWPM 20-81-11, LEAK AND OPS CHECK GOOD (SEE ALSO AALA202110188983, AALA202110184766, AALA202110185635, AALA202110186042).