Toshiba MMY-MUP0801HT8P-E Installation Manual page 21

Airtightness test
After the refrigerant piping has been finished, execute an airtight test.
For an airtight test, connect a nitrogen gas canister as shown in the figure on this page and apply pressure.
• Be sure to apply pressure from the service ports of the packed valves (or ball valves) at the liquid side and gas
side.
• An airtight test can only be performed at the service ports at the liquid side and gas side on header unit.
• Close the valves fully at the gas side and liquid side. As there is a possibility that the nitrogen gas will enter into
the cycle of outdoor units, re-tighten the valve rods at the liquid side before applying pressure.
• For each refrigerant line, apply pressure gradually in steps at the liquid side and gas side.
Be sure to apply pressure at the gas side and liquid side.
WARNING
Never use oxygen, flammable gases, or noxious gases in an airtight test.
Main piping
Valve details
To gauge
manifold
To outdoor unit
Liquid-side
Gas-side valve
Liquid-side
valve
service port
To
outdoor
unit
Gas-side
Piping at site
service port
Piping at site
Connected to other follower units
39-EN
Low pressure
gauge
Connected to indoor unit
Gas side valve fully closed
Header outdoor unit
Service port
Brazed
Copper pipe
Brazed
Service port
Liquid valve fully closed
Able to detect a serious leakage
1. Apply pressure 0.3 MPa (3.0 kg/cm
2. Apply pressure 1.5 MPa (15 kg/cm
Available to detect slow leakage
3. Apply pressure 4.15 MPa (42.3 kg/cm
• If there is no pressure decrease after 24 hours, the test is passed.
NOTE
However, if the environmental temperature changes from the moment of applying pressure to 24 hours after that,
the pressure will change by about 0.01 MPa (0.1 kg/cm
the test result.
REQUIREMENT
When pressure decrease is detected in steps 1-3, check the leakage at the connecting points.
High pressure Check the leakage using a foaming agent or other measures and seal the leak with re-brazing, flare retightening
gauge
or other methods. After sealing, execute an airtight test again.
Gauge
V V
L H
manifold
Reducing
valve
Copper
pipe
Nitrogen
gas
– 20 –
G) for 5 minutes or more.
2
G) for 5 minutes or more.
2
2 G) for approx. 24 hours.
G) per 1°C. Consider the pressure change when checking
2
EN
40-EN