Fixing a biofertiliser plant's compost turner hydraulics through the hot season

The windrow turner works in the open, where fermentation heat from the pile combines with high ambient temperature; the hydraulic oil temperature peaked near 85°C, accelerating seal ageing and increasing internal leakage, and the motions grew slower day by day until the machine simply stalled.

The usual response in previous years was to stop during the heat of the day, letting output give way to the weather.

Locating the heat source by temperature measurement: besides the environment, prolonged high-pressure relief at the relief valve was the main internal heat source - the system pressure was set too high, above what the actual load required.

The fix came in three steps: reset the system pressure against the measured load, sharply reducing relief time; add an air-cooled hydraulic oil cooler and clean the fins of the existing cooler; and switch to a high viscosity index anti-wear hydraulic oil. Afterwards, peak oil temperature under the same conditions fell by 16°C, and the machine ran through the whole hot season without stopping.

For an overheating hydraulic system, check internal leakage and relief first, cooling capacity second. Many high-temperature problems are really pressure setting problems.

Seasonal faults have to be dealt with one season ahead. Waiting until the problem season arrives is already too late.

When a hydraulic system stalls in the hot season, most plants' first reaction is to "add a bigger cooler." This case first measured temperatures to locate the heat source and found that the main internal source was not the environment but prolonged high-pressure relief at the relief valve: the system pressure was set above what the actual load required, and the surplus power all turned into heat. Adjust the pressure first, clean the cooler second, and only then consider an oil change; across the three steps the peak oil temperature fell 16°C with no major hardware added. The order matters in treating hydraulic overheating: find the heat source first, spend money on cooling second - reverse the order and you waste money.