Midea MV5-X450W/V2GN1-AU - Pressure Observation

R410A All DC Inverter V5 X Series 50Hz MCAC-VTSM-2015-10
116 Installation
No.
Phase (phase-in pressurization)
Criteria
1
Phase 1: large leakage after over three minutes of pressurization with 3.0kgf/cm
2
.
No pressure drop
after modification
2
Phase 2: major leakage after over three minutes of pressurization with 15. 0kgf/cm
2
.
3
Phase 3: small leakage after over 24 hours of pressurization with R410A: 40.0kgf/cm
2
.
10.2.2 Pressure observation
1. System pressure should be maintained for 24 hours. When pressure change is related to temperature
change according to below calculation, it means there are on leakage. If pressure falls, identify and address
the leakage source.
2. Modification method
When ambient temperature difference is ±1°C, the pressure difference shall be ±0.1kgf/cm
2
.
Modification formula: Real value = pressure of pressurization + (temperature of pressurization – temperature
during observation)x0.1kgf/cm
2
A pressure drop can be identified by comparing the modification value with pressurization value.
3. General method for identifying the source of a leak
Detection process involves three general steps.
1) Audio detection for identifying large leaks.
2) Touch detection -----place hand at the joint to feel the leakage
3) Soap water detection is used to identify small leaks. Escaping gas will create bubbles at the leak point after
soapy water is applied.
4) Detection by use of halogen leak detector
Use a halogen leak detector when finding the source of difficult to detect leakages.
a. Keep nitrogen at 3.0kgf/cm
2
.
b. Supplement refrigerant to 5.0kgf/cm
2
.
c. Use halogen leak detector, methane leak detector and electric leak detector for detection.
d. If the leak source cannot be found, continuously pressurize to 40.0kgf/cm
2
(R410A) and then detect again.
4. Caution
1) The air tightness test is conducted by pressurized nitrogen (R410A system: 40.0kgf/cm
2
).
2) Oxygen, flammable gas and toxic gas shall not be used to conduct air tightness test.
3) Before pressure reading, let the system rest for several minutes till pressure is stable.
4) After test is complete, reduce system pressure to 5~8kgf/cm
2
and then conduct pressure-keeping and
storage.
5) If pipeline is too long, conduct phase-in detection.
a. Inner side of pipeline
b. Inner side of pipeline + upright
c. Inner side of pipeline + upright+ outer side of pipeline
Outdoor unit
Indoor unit
Nitrogen
Liquid pipe
Gas pipe
Liquid side
shut-off valve
Gas side hut-off valve