Leak Test - Toshiba HFC R407C Service Manual

Airtight test
Carry out an airtight test after the refrigerant piping is complete. For an airtight test, connect a nitrogen
gas bottle as shown, and apply pressure (use oxygen-free nitrogen, OFN).
The pressure test must be completed before supplying power to ensure that the Multi Controller PMVs
(pulse modulating valves) are open.
The test must be completed with the indoor units, Multi Controllers and outdoor unit connected.
• Be sure to carry out the test from the service ports of the packed valves at the discharge gas,
liquid and suction gas side.
• Keep all of the valves at discharge gas, liquid and suction gas sides fully closed. Nitrogen may
enter the cycle of the outdoor unit. Therefore, retighten the valve rod before applying pressure.
(For all valves.)
• For each refrigerant line, apply pressure gradually at the discharge gas, liquid and suction gas
sides.
Never use oxygen, or a flammable noxious gas.
Detailed drawing of packed valve
Service port at gas
discharge side
Service port at
liquid side
To detect a large leakage
Step 1: 0.3 MPa (3 kg/cm
Step 2: 1.5 MPa (15 kg/cm
To detect a fine leakage
Step 3: 3.0 MPa (30 kg/cm
• Check for a reduction in pressure.
If there is no reduction in pressure this is acceptable.
If there is a reduction in pressure check for a leakage.
(Note: If there is a difference of ambient temp. between when the pressure was applied and 24 hours later,
then pressure could change by approx. 0.01 MPa (0.1 kg/cm
Refrigerant pipe installation

Leak test

To
manifold
Service port at
gas suction side
2
G) Apply pressure for 3 minutes or more
2 G) Apply pressure for 3 minutes or more
2
G) Apply pressure for 24 hours
Packed valve fully closed
(gas suction side)
Inverter outdoor unit
Brazed
Service port
Flare
connection
Service port
Packed valve fully
Flare
closed (liquid side)
connection
Packed valve fully closed
(gas discharge side)
2
G) - so correct the pressure change.
Low High
pressure pressure
gauge gauge
Gauge
manifold
Regulator
Copper
pipe
ø 6.4
Copper
pipe
ø 6.4
Nitrogen
gas
69