THE ENEMIES WITHIN
This hard, brittle contaminant forms on the inside of copper pipe when a technician brazes without flowing a dry nitrogen purge.
What are copper oxides?
The visual presence of this thin metallic film on steel surfaces, like bearing journals, is the "smoking gun" of severe acid and moisture contamination.
What is copper plating?
The first critical step in the structured cleanup sequence, which ensures contaminated refrigerant is not vented or reused.
What is recovery (Recover)?
This high-pressure, dry gas is used to drive the chemical solvent and loosened contaminants out of the line set and into a containment bucket.
What is dry nitrogen?
This non-negotiable target vacuum level is required to flash and remove trace moisture and solvent before introducing new oil.
What is below 500 microns?
This fine, abrasive particulate is released during a motor burnout and acts like sand-blasting medium inside the refrigeration circuit.
What is carbon?
If residual acid is not cleaned out after a motor burnout, it quickly strips the protective enamel from the new stator coils, causing this catastrophic failure.
What is a repeat burnout?
Unlike standard driers that only capture solid debris, a heavy-duty cleanup filter drier is loaded with this expanded desiccant blend to chemically neutralize massive acid pools and sludge.
What is activated alumina and activated charcoal?
Applying an open torch flame to a contaminated burnout system to de-braze components can vaporize trapped acid-oil sludge, releasing this highly lethal gas.
What is phosgene gas? (Also accepts hydrofluoric acid fumes)
A destructive chemical reaction that occurs when fresh polyolester (POE) oil is introduced to moisture, breaking down the oil into organic acids.
What is hydrolysis?
Non-condensable gases natural collect at this highest point in the refrigeration grid, where they act as a thermal barrier.
What is the condenser?
This simple, color-changing field diagnostic test is used to measure the acid concentration in a system’s lubricant.
What is a chemical titration test kit?
Because of this natural physical function, the compressor’s oil sump is the primary collection sink for circulating acid, sludge, and moisture, making a full oil drain & flush essential.
What is gravity / settling? (Or "acting as a collection sink")
Instead of applying heat or a torch to remove a failed burnout compressor, the safe practice is to use this hand tool.
What is a tubing cutter?
Temporary suction-line cleanup driers must be removed shortly after the system tests neutral because they create this operational hazard.
What is a structural restriction? (Also accepts lowering suction pressure/raising compression ratio)
These two highly corrosive compounds form when moisture inside a system reacts with the refrigerant and oil.
What are organic and inorganic acids?
To measure improvement after a cleanup, a technician must first document suction/head pressure, amp draw, voltage, and splits to establish this reference.
What is a baseline performance audit?
These access fittings must be installed across the suction-line cleanup filter-drier to monitor Delta-P ($\Delta P$) and prevent a restrictive pressure drop.
What are Schrader access fittings?
These five critical system components contain internal seals, precision orifices, and oil traps, and must never be subjected to chemical solvent flushing.
What are the compressor, metering devices (TXV/EEV), suction accumulator, liquid receiver, and multi-port reversing valves?
When retrofitting a system from a legacy CFC or HCFC to a modern HFC, the replacement charge weight is typically this percentage less than the original data plate specification.
What is 5% to 15% less?
A physical contaminant often left behind in the lines if the cut ends of the copper tubing are not properly prepped before assembly.
What are un-deburred metal slivers?
Trapped non-condensable gases in the condenser trigger these four unmistakable operational symptoms.
What are high discharge head pressure, a spiked compression ratio, increased motor amp draw, and thermal degradation of the oil?
This process must be executed for 4 to 24 hours under active observation before checking if the oil’s TAN (Total Acid Number) has returned to neutral.
What is monitor/testing? (Or "Run/execute the system under observation")
Attempting to flush this low-velocity component is rarely effective because its internal baffles and oil trap prevent the solvent from reaching all surfaces, meaning it should be completely replaced after a severe burnout.
What is the suction accumulator?
This is the primary reason modern HFC refrigerants paired with synthetic POE oils require a reduced charge weight compared to legacy equivalents.
What is a lower mass density profile? (They occupy a higher physical volume per pound)