Fisher & Paykel 635 Active Smart Service Manual page 103

321144
Step 4:
Connect a nitrogen bottle to the in-line pressure gauge by means of a hose with a Schrader valve
depressing key in the hose coupling.
Step 5:
Open the nitrogen bottle fully with the regulator backed off.
Step 6:
Increase the regulator pressure in the circuit being tested to 150 psi.
Step 7:
Close the nitrogen bottle valve, then back off the pressure regulator.
Step 8:
Disconnect the hose coupling to the Schrader valve fitting.
Step 9:
Seal the Schrader valve with its sealing cap.
Step 10:
Use a bit of masking tape to mark the face of the pressure gauge at the set pressure. Record date and time
on the tape also.
Step 11:
Check all exposed brazed joints with soap bubbles, including the joints on the in-line pressure gauge.
Step 12:
Allow the pipe circuit under test to sit on drop off test. This could take a number of days for a result.
NOTE: In some cases a leak may not be found by pressurising the circuit, whereas a vacuum pulled on the
same circuit will. Keep this in mind as oil within the circuit can block a hole.
In some cases, if the brazed joint is warmed while under pressure, this can thin the oil and help to expose
the leak. A heat gun or hair dryer is useful.
Diagram 0
103