Repair, Component Replacement and System Reassembly
Repair, component replacement and system reassembly
This domain tests whether you can open, repair and reassemble a MAC system without introducing moisture, dirt, wrong oil or incorrect seals, and whether the repair is verified afterwards.
Core rules
- Recover refrigerant before opening. Cap or plug open lines immediately. Clean the area around joints before dismantling.
- Use the correct O-ring material and lubricant for the refrigerant and oil. Never use petroleum grease. Fit new seals where specified and torque to manufacturer data.
- Replace the receiver-drier or accumulator whenever the system is opened, because it is saturated once exposed to air.
- Balance oil: drain and measure oil from a removed component where possible, and add the specified amount to the replacement or compressor. Too little oil causes seizure; too much reduces heat transfer.
- Check routing, clearance, mounting and connector engagement. Do not over-tighten flare or O-ring joints.
Worked example
A condenser is replaced after impact damage. Recover the charge, record the amount, remove the condenser and note the oil trapped in it. Fit new O-rings, add the manufacturer-specified oil compensation, fit a new drier, evacuate and leak-test before charging by weight. The reasoning is that impact may have moved oil and introduced debris; the drier protects the new component.
Traps
- Reusing the old drier.
- Guessing oil quantity.
- Using the wrong O-ring or grease.
- Leaving lines open while fetching parts.
- Over-torquing joints and damaging seals.