Carrier X-POWER Series Service Manual page 113

Carrier service manual
3.2. Air Tight Test
3.2.1 Purpose and operation procedure of air tightness test
3.2.1.1 Purpose
Search leak source, make sure there is no leakage in system to prevent system fault due to leakage of
refrigerant.
3.2.1.2 Operation tips
Subsection detection, overall pressure-keeping, grading pressurization.
3.2.1.3 Operation procedure
1. After piping of indoor unit has been connected, weld port of high-pressure side piping.
2. Weld low-pressure side piping with connector for pressure gauge together.
3. Charge nitrogen slowly into pressure gauge connector to conduct air tightness test.
3.2.2 Operation of air tightness test
3.2.2.1 Operation procedure
1. When conducting air tightness test, make sure that gas pipe and liquid pipe are kept in full-shut status;
otherwise, nitrogen might enter the circulation system of outdoor unit. Both gas valve and liquid valve
need to be strengthened before pressurization d.
2. Each refrigerant system shall be slowly pressurized from the two sides of gas pipe and liquid pipe.
3. Make use of dry nitrogen as medium to conduct air tightness test. Phase-in control diagram of
pressurization is as follows:
No. Phase (phase-in pressurization)
1 Phase 1: appear large leakage after over three minutes of pressurization with 3.0kgf/cm
2 Phase 2: appear major leakage after over three minutes of pressurization with 15. 0kgf/cm
3 Phase 3: appear small leakage after over 24 hours of pressurization with R410A: 40.0kgf/cm
3.2.2.2 Pressure observation
1. Pressurize to regulated value and maintain 24 hours. When modifying pressure according to variation
of temperature, it is qualified if pressure drop does not happen. If pressure falls, find out the leak source
and modify it.
2. Modification method
When ambient temperature difference is ±1 , the pressure difference shall be ±0.1 kgf/cm
Modification formula: Real value = pressure of pressurization + (temperature of pressurization –
temperature during observation) x 0.1kgf/cm
You can find out whether the pressure drops or not by comparing the modification value with
pressurization value.
3. General ways for searching leak source
Conduct detection through three phases; find out leak source when pressure drop happens.
1) Audition detection-----hear large leakage sound
2) Hand-touching detection-----place hand at the joint of pipeline to feel whether there is leakage
3) Soap water detection-----bubbles shall burst out from leak source.
Installation
2
R410a DC Inverter 60Hz
Criteria
2
.
No pressure drop
2
.
after modification
2
.
2
.
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