Hale HFM - Manual (Page 18)

5. Final Test Before Housing Engine after a Fire or Drill. In addition to regular lubrication and
maintenance to the pump, the following procedure is recommended to assure proper
operation under emergency conditions:
a) Open discharge valves and remove caps.
b) Close drain valve(s).
c) Tighten suction caps.
d) Pull a prime until the compound gauge reaches about 20 inches of vacuum.
e) Watch gauge - if vacuum drops more than 10 inches in 10 minutes, an air leak is present.
All air leaks must be corrected before the pump may be considered fully serviceable.