Airtight Test - Toshiba MiNi-SMMS Installation Manual

Airtight test

After the refrigerant piping has finished, execute an airtight test. For an airtight test, connect a nitrogen gas bomb as
shown in the figure below, and apply pressure.
• Be sure to apply pressure from the service ports of the packed valves (or ball valves) at liquid side, discharge gas
side, and suction gas side.
• An air tight test can be only performed to the service ports at liquid side, discharge gas side, and suction gas side
of the outdoor unit.
• Close fully valves at liquid side, discharge gas side, and suction gas side. As there is possibility that nitrogen gas
enters in the refrigerant cycle, re-tighten the valve rods before applying pressure.
(Re-tightening of the valve rods are unnecessary for valves at discharge gas side because they are ball valves.)
• For each refrigerant line, apply pressure gradually with steps at liquid side, discharge gas side, and suction gas
side.
Be sure to apply pressure to suction gas side, discharge gas side, and liquid side.
Never use "Oxygen", "Flammable gas" and "Noxious gas" in an airtight test.
Connected to indoor unit
Main pipe
STEP 1 : Apply pressure 0.3MPa (3.0kg/cm
STEP 2 : Apply pressure 1.5MPa (15kg/cm
STEP 3 : Apply pressure 3.73MPa (38kg/cm
• Check pressure down.
No pressure down: Accepted

However, if there is difference of ambient temp. between when pressure has been applied and when

24 hours passed, pressure changes by approx. 0.01MPa (0.1kg/cm²G) per 1°C. Correct the pressure.
Leaked position check
When a pressure-down is detected in STEP 1, STEP 2, or STEP 3, check the leakage at the connecting points.
Check leakage with hearing sense, feeler, foaming agent, etc, and perform re-brazing or re-tightening of flare if
leakage is detected.
REQUIREMENT
Packed valve fully closed
(Gas side)
Outdoor unit
Brazed
Service port
Fully closed
Ball valve fully closed
(Liquid side)
2
G) for 3 minutes or more.
2
G) for 3 minutes or more.
2 G) for approx. 24 hours.
Pressure down: Check the leaked position.
Low-
pressure
gauge
VL
Ø6.4
Copper pipe
Ø6.4
Copper pipe
Service port

Available to detect a gross leakage

Available to detect slow leakage
16
High-
pressure
gauge
Gauge
VH
manifold
Reducing
valve
Nitrogen gas

