Pressure Testing Of The Refrigeration System - Fisher & Paykel RF175W Service Manual

13 PRESSURE TESTING OF THE REFRIGERATION
SYSTEM
The use of the in-line pressure gauge can speed up and eliminate the incorrect diagnosis of a leak
within a refrigeration system. In some cases it has been found to be the services manifold that
was being used that was leaking and not the system. There are very few parts on the in-line
pressure gauge that can leak.
Rule one:
In pressure testing any cabinet, before disconnecting any joint please be 100% sure that it is not
the joint that is at fault, otherwise a lot of time can be lost looking for a joint/leak that doesn't exist.
Rule two:
Only use dry nitrogen to pressure test a system.
NOT REFRIGERANT OR COMPRESSED AIR.
Rule three:
Don't over pressurise the system. It could be dangerous.
How to use the In-line Pressure Gauge:
Step 1:
Cut and connect the pipe circuit to be tested to the in-line pressure gauge and braze this joint.
Step 2:
At the other end of the pipe circuit being tested, crimp off the pipe with crimp off pliers and braze
this end off to totally seal the circuit.
Step 3:
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 4:
Open the nitrogen bottle fully with the regulator backed off.
Step 5:
Increase the regulator pressure in the circuit being tested to 150 psi.
Step 6:
Close the nitrogen bottle valve, back off the pressure regulator.
Step 7:
Disconnect the hose coupling to the Schrader valve fitting.
Step 8:
Seal the Schrader valve with its sealing cap.
Step 9:
Use a bit of masking tape to mark the face of the pressure gauge at the set pressure. Record the
date and time also.
Step 10:
Check all exposed brazed joints with soap bubbles, including the joints on the in-line pressure
gauge.
NEVER OXYGEN
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