More On Coil Cleaning
External Coil Surface
Coils, both indoor and outdoor, should be cleaned regularly as part of an on-going maintenance program:
A build up of dirt on coils can cause increases in evaporating and condensing temperatures. The coils are the parts of the system where the heat transfer takes place and dirt on a coil will form a barrier to heat transfer -effectively insulating the coil. This will lead to an overall increase in the running costs of any refrigeration and air conditioning system.
Heavy dirt build up can also clog the coil and reduce the air flow: on indoor coils this will contribute to poor indoor air quality and can act as a source of contamination.
The function of the indoor coil is to remove heat from mechanically circulated air. All of the air in the building will ,in time, pass through these coils. Eventually, due to the large volumes of air that passes through the coil on a daily basis there will be an accumulation of dirt and possibly bacteria on the fins and tubes of the coil. Where no filters are used the problem of dust and contamination are of course much greater and regular cleaning is even more essential.
Air cooled condensers operate at a high temperature and the air entering them is rarely, if ever, filtered. They are often exposed to extremes of environmental conditions eg. in coastal areas, aluminium finned condensers particularly, are subject to corrosion by the saline atmosphere.
The dirt that accumulates on these coils comes from airborne particles, insects, leaves etc. which in conjunction with the high temperature of the coil can become “baked” on and prove very difficult to remove if not maintained on a regular basis.
Internal flushing of refrigerant pipes
A system failure can result in contaminants: sludge, acids, carbon residues and moisture. These contaminants must be removed from the system before it is restarted, this means flushing.
Descaling of water pipes
Open re-circulating systems such as cooling towers and water-cooled condensers can suffer severely from lime scale build up. If left, it will reduce water flow, increase head pressure and eventually reduce system capacity. In severe cases it can lead to system overload and mechanical failure.
Internally, ice machines, suffer from lime scale build up that, again, will affect the efficiency of the unit and lead to damage of components.