Air Conditioning Service Tips

Air-conditioned machinery is no longer a luxury but a necessity due to the long workdays and dusty conditions that are part of farming. The system consists of a compressor, hoses, evaporator, condenser, system drier, flow valves, and refrigerant. Mixed in with the refrigerant is a special oil that keeps the moving parts in the compressor lubricated.

There are also two refrigerant pressure pathways: the low and high sides. The low side has the refrigerant in a gaseous state while it is a liquid on the high side.

System operating pressure is directly linked to the thermal load but, more importantly, the ambient and under the hood temperature of the equipment. A hot day with the engine working hard will significantly raise the high side pressure. System pressure is continually going up and down depending on thermal load and engine rpm.

When the hoses age or are oil-soaked from an engine leak, they become porous. When the system pressure reaches a critical point, the refrigerant then starts to push through the hose and into the atmosphere. The result is poor performance due to a lack of refrigerant but no visible sign of a leak.

Keeping the engine clean goes a long way in preventing A/C hose failure. The system also employs many rubber-type O-ring seals that, over time, will leak slightly. If the machine is older, it will inherently lose some refrigerant even though nothing is wrong.

When this occurs, moisture is introduced and mixes with the refrigerant and creates acid. It then deteriorates all the internal components. You are now faced with a repair bill in the thousands of dollars. But this does not have to be the case.

Every few years, the system is meant to be discharged, evacuated (remove moisture), and refilled with the proper amount of fresh refrigerant and oil. Sadly, few do this.

If they did, the air conditioner would outlast the machine and freeze them out.


Choosing a Replacement Radiator

A typical scenario goes like this: An engine in a farm machine or truck needs a new radiator and is beginning to run hot. You shop around and find a wide discrepancy in price and decide on the least expensive replacement.

You are proud of your wise financial decision… that is until it runs just as hot or even slightly hotter than with the old radiator.

How can this be? Is there something else wrong with the engine? It cannot be the radiator, right? The liquid’s job is to cool the engine, and it is the radiator’s task to cool the liquid. For this to occur, it must be designed for the heat rejection of the engine.

Just because it fits in place has nothing to do with how it performs. A radiator consists of the tanks, headers, and core. It is the core that has the most influence on its efficiency. Heated coolant is circulated through the core. There, small quantities of coolant travel through the tubes that have fins attached to them.

This is where the heat transfer from the liquid to the air occurs. The design of the tubes and fins are paramount to this. Specifications such as fin density per square inch, the size, and shape of the tubes and fins along with the material used to attach the fins all add up to making the radiator efficient.

The best choice is to buy a factory replacement. It will have the heat rejection requirement for that engine. There are excellent aftermarket brands that produce the same heat rejection as the factory unit but are usually not the lowest cost option.

They make the sale, but your engine pays the price!