Toj from AVI services the AC system on a Freightliner with a Detroit engine using a triple-R machine.
Pre-Service Visual Inspection:
- Check Belts: Identified and plan to replace a frayed belt not connected to the AC but requiring attention.
- Compressor Check:
- Measure the clutch air gap with a feeler gauge, adhering to compressor-specific specs.
- Inspect mounting bolts for tightness, as a loose compressor can cause “catastrophic failure.”
- Drier Inspection: The drier label indicates “oil amount and type is none,” signifying an enclosed oil system within the compressor (common in semis with sleepers to prevent oil loss in rear evaporators).
- Service Port Caps: Remove caps and inspect O-rings. Toj recommends replacing the O-rings inside the caps with the correct OEM size to prevent future leaks after recharging. Emphasize not losing the caps and securing them properly.
Triple-R Machine Operation (Recovery and Recharge):
- Initiate Full Cycle: Select “full cycle” on the machine.
- Set Vacuum Time: Set the vacuum time for an R-134a system to 45 minutes.
- Select Port: Choose the low-side port for charging.
- Set Refrigerant Amount: Check the truck’s AC label (2.88 pounds R-134a in this case) and input the amount.
- High Voltage Check: Press “no” as it’s not an electric vehicle.
- Safety & Prep: The machine checks pressure and clears lines. Wait for the prompt.
- Connect Hoses: Connect high-side and low-side service hoses and open the couplers.
- Start Vehicle: When prompted for low refrigerant pressure, start the vehicle to build pressure.
- Recovery & Vacuum: The machine recovers refrigerant (and oil, if present) and then runs the 45-minute vacuum.
- Leak Check: A 5-minute leak test follows the vacuum.
- Charging: The machine moves straight into charging the system with the specified 2.88 pounds of refrigerant.
- System Health Check: The machine performs a system health check, displaying ambient temperature, pressures, and an overview.
- Disconnect: Close valves, disconnect couplers, turn off the truck, and allow the machine to clear itself.
- Inject Oil: Inject the necessary amount of oil based on how much was pulled out. The process is then “complete.”
