Knowing the correct refrigerant charge for your John Deere tractor is crucial for optimal cooling performance. While a John Deere Refrigerant Capacity Chart isn’t readily available, this guide provides practical advice for charging your system, specifically focusing on converting from R-12 to R-134a.
R-134a Charging in John Deere Tractors
When transitioning from R-12 to R-134a, a common rule is to use 80% of the recommended R-12 charge. For a John Deere tractor with a Sound-Gard cab, around 3.5 lbs of R-134a generally yields the best results. However, starting with 3 pounds and running the system for 10-15 minutes at 1200-1500 RPM with the thermostatic switch on maximum and blowers on high allows for system normalization and pressure/temperature assessment.
If cooling seems insufficient, add refrigerant in small increments (an ounce or two at a time), monitoring the air duct temperature between additions. Remember, the thermostatic switch adjustment significantly impacts air duct temperature. Each switch varies, affecting the compressor shut-off point based on evaporator temperature. Avoid excessively cold settings to prevent evaporator freeze-up.
Importance of Filters and Airflow
Maintaining clean cab filters is paramount. A clogged recirculation filter above the grille restricts already-cool air recirculation, forcing the system to draw in more ambient air, thereby reducing cooling efficiency.
Both the 4230 and 4030 John Deere manuals recommend a 4 lb refrigerant charge. Rely on weight measurements for accurate charging with R-134a, as the sight glass may still show bubbles even with a full charge. Modern John Deere receiver-driers often lack sight glasses altogether.
Oil and Leak Detection
Typically, additional oil isn’t necessary when using a rebuilt John Deere compressor, as it usually contains sufficient oil. Excessive oil can be as detrimental as insufficient oil. Consider using leak-detection dye or pre-dyed R-134a to simplify future leak identification.
Conclusion
While a specific John Deere refrigerant capacity chart might not be available, understanding the principles of charging with R-134a, maintaining clean filters, and monitoring system pressures and temperatures ensures optimal AC performance in your John Deere tractor. Always prioritize accurate weight measurements when charging and consider using leak detection dye for preventative maintenance.
