9-6. In case refrigerant is leaking
●
Never attempt to charge additional refrigerant when refrigerant has been leaking
from the unit. Follow the procedure described below to locate points of leaks and
carry out repairs, then recharge the refrigerant.
(1) Detecting Leaks
• Use the detector for R407C to locate refrigerant leak
points.
(2) Recovering refrigerant
• Never release the gas to the atmosphere, recover
residual refrigerant using the refrigerant recovery unit
for R407C, instead.
• Do not reuse the recovered refrigerant because its
composition will have been altered.
(3) Welding leaking points
• Confirm again that no residual refrigerant exists in the
unit before starting welding.
• Weld securely using flux and wax for R407C.
• Prevent oxide film from forming inside the tubes
utilizing substitution with nitrogen (N2) in the
refrigerant circuit of the unit. Leave ends of tubes open
during welding.
(4) Checking for sealing
• Use nitrogen gas for the pressurized gas, and never
use a refrigerant other than R407C. Also do not use
oxygen or any flammable gas.
(5) Evacuation
•
Use a solenoid valve-installed vacuum pump so
that even if power is cut off in the middle of evacuation
of air due to a power interruption, the valve will prevent
the pump oil from flowing back.
• The equipment may be damaged if moisture remains
in the tubing, thus carry out the evacuation thoroughly.
• When using a vacuum pump with exhaust air volume
more than 25L/min. and ultimate vacuum pressure rate
of 0.05Torr:
47
(2). Recovering refrigerant
OK
(3). Welding leaking points
OK
(4). Checking for sealing
OK
(5). Evacuation
OK
(6). Recharging
(1). Detecting leaks
OK
CAUTION
Standard time of evacuation
Length of tubing
Less than 10 m
More than 10 m
Time
More than 10 min. More than 15 min.
