16
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, gas side, and
balance pipe side.
• An airtight test can be only performed to the service ports at liquid side, gas side, and balance side of the header
unit.
• Close fully valves at liquid side, gas side, and balance 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 gas side of MMY-MAP0501
∗
and MAP0601
∗
because they are ball valves.)
• For each refrigerant line, apply pressure gradually with steps at liquid side, gas side, and balance side.
Be sure to apply pressure to liquid side, gas side, and balance side.
REQUIREMENT
Never use “Oxygen”, “Flammable gas” and “Noxious gas” in an airtight test.
STEP 1 : Apply pressure 0.3MPa (3.0kg/cm
2
G) for 3 minutes or more.
Available to detect a gross leakage
STEP 2 : Apply pressure 1.5MPa (15kg/cm
2
G) for 3 minutes or more.
STEP 3 : Apply pressure 3.73MPa (38kg/cm
2
G) for approx. 24 hours.
Available to detect slow leakage
• Check pressure down.
No pressure down: Accepted Pressure down: Check the leaked position.
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.
V
L
V
H
Connected to indoor unit
Main pipe
Packed valve fully closed
(gas side)
Header outdoor unit
Low-
pressure
gauge
High-
pressure
gauge
Gauge
manifold
Brazed
Service
port
Service port
Ø6.4
Copper pipe
Ø6.4
Copper
pipe
Fully
closed
Fully
closed
Reducing
valve
Nitrogen
gas
Packed valve fully closed
(liquid side)
Packed valve fully closed
(balance)
Connected to other follower outdoor units
Detailed drawing of packed valve
To gauge manifold
Gas-side
service port
Gas-side
packed valve
To outdoor
unit
To outdoor unit
To
outdoor
unit
Liquid-side
packed valve
Liquid-side
service port
Balance
packed valve
Balance
service port
Piping at site
Piping
at site
Piping
at site
Содержание MAP0601HT7
Страница 61: ...EH99834001 ...