Gree GWC09AA, Installation And Service Manual

Page: 86 / 136

GREE Service Manual GWC09AA / K5NNA6A Page 86
In general, the Gree Air–Conditioners are Factory Tested for compliance with
international standards and regulations. The factory test also includes a strength
test. The HC R-290 Air-Conditioner is rated for a Maximum Allowable Pressure
(PS) of 40 bar (4.0 MPa). For the new product installation and commissioning a
sole Leak Test, using a reliable Electronic HC Leak Detector, has to be carried
out.
Regular Preventive Maintenance requires activities following Best Servicing
Practices by employing indirect refrigerant detection techniques. Probably these
activities may indicate requirements to carry out further direct detection proce-
dures. Indirect checks for leakages include manual checks of the system and its
operation conditions against the design operation conditions.
These activities will include analysis of the following parameters and conditions:
1. System Pressure
2. Temperatures
3. Compressor Current
Refrigerant Loss Indications shall be followed by comprehensive direct
tightness testing method of the operational system by the use of the HC Leak
Detector.
Refrigerant Loss Indicators are:
1. All deviations from normal operation conditions analysed from the above-
mentioned indicators.
2. Any visible damage of the system.
3. Damage of pressure switch and sensors.
4. Corrosion and oil leaks.
5. Vibration, abnormal noise, ice formation.
6. Insufficient cooling capacity.
Having these preconditions of a sealed system in mind, in case of malfunction,
after any modification or repair to the AC system (intervention into the refriger-
ant circuit) at least the affected part (refrigerant circuit piping or piping
connections) shall be subject for a strength test (pressure test). The strength
test pressure shall not exceed the strength test pressure applied to components
by the manufacturer. During on-site activities, the complete AC system is sub-
ject for a pressure test.
The Pressure Test Value for the AC system (Strength Test) is at 1.1 times of
the Maximum Allowable Pressure (PS), which is indicated at the outdoor units
data plate.
Pressure Test Value = 1.1 x PS (40 bar x 1.1) = 44 bar (4.4 MPa)
Procedures subsequent to the Pressure Test (Strength Test):
A Refrigerant Leakage Detection (Leak Test) must be carried out after Pres-
sure Test.
Testing the system for leaks needs to pressurise the refrigerant circuit with the
use of OFDN or if the equipment is available with a mixture of OFDN and Hydro-
gen (95% N
2
and 5% H
2
) called “Forming Gas” in connection with an electronic
N
2
/H
2
Trace Gas Leak Detector.
If piping, compo-
nents or areas
are covered by
oil, or you may
hear the noise of
escaping
refrigerant
(rough leaks),
this may clearly
indicate that
there is a
potential leak
existing!
Replace and
tighten valve-
caps, otherwise
leakage is guar-
anteed!