Articles / Contamination and oil draining
Air conditioning system contamination is a controversial subject, mainly when it comes to warranty issues. Warranties on components are declined when there are signs of contamination found in the failed components.
When replacing components on an air conditioning system, it is important to note why the previous system failed. Even though one uses the correct flushing solvent and uses the best equipment to clean a system of any contamination before fitting new components, it is still possible for some contamination to be stuck somewhere in the system. This is also the reason why it is recommended to replace all components when replacing failed components.
Contamination can be defined as any substance which should not be in that particular air conditioning system, e.g. moisture. But do note that the incorrect oil can also be a contaminant – anything that should not be in that particular system is a contaminant.
Air conditioning systems can be contaminated with metal particles from the normal wear of the compressor and tiny amounts of water moisture. Contamination can cause a system to fail. Protection against contamination is provided by the filter screen on the Expansion Tube and the desiccant in the bottom of the dryer or accumulator. Other forms of contamination may be the wrong kind of oil, wrong kind of liquid charge or other material that will interfere with the cooling system. Almost 100% of moisture is normally removed from the system when it is evacuated prior to installing (R12 or R134a), but flushing the entire system will be the only way to remove any particles.
Even after flushing it is important to make sure the system is clean. Burnt oils can for example not be completely removed even after flushing more than once, and will start dissolving after a few weeks of normal use. This will then cause system failure, with the new components needing to take the blame for the failed system, while this is in fact not the case.
In situations where two or maybe even three compressors are fitted and fail in the same way, only to have the last unit work fine, it is probably a case of a contaminated system. The new compressor being fitted acts as filters. So the contaminant gets stuck in the compressor and the compressor fails, with each new compressor fitted filtering out more contaminant, until the system is contaminant-free or close enough to it that it seems that last fitment is lasting. Unfortunately by this time the fitment center is so upset with their supplier’s “poor components”, that the relationship has taken a beating and all profits are lost.
Making 100% sure that the air conditioning system is contaminant free, will not only save you money, but probably help keep the stress levels down as well.