SERVICE AND MAINTENANCE
Flushing out the gremlins
Mike Creamer of Business Edge talks about flushing systems effectively and the benefits of the F3OS system.
U
ntil now, there has been no sure way of effectively flushing a refrigeration circuit, yet thousands of acr systems require thorough and effective flushing every year for one of the following reasons:
Refrigerant/oil retrofit
When retrofitting systems with a new alternative refrigerant, all traces of mineral oil must be removed prior to the injection of synthetic oil. Otherwise, compressor failure
is likely to occur. It may also be necessary to remove a mineral oil in order to replace it with an alternative mineral oil or to remove a synthetic oil, substituting this with a mineral oil. Whatever the requirement, mixing of different oil types may ether damage the compressor or shorten its working life. Compressor motor burn out
The presence of acids will attack compressor motor windings, causing progressive winding deterioration, which results in the distribution
of particulate matter throughout the system, until the compressor ultimately fails. The contaminated oil containing acid particulates must be thoroughly flushed from the system in order to avoid subsequent compressor failures. Particulates left in a system can block the TEV and/or vital small diameter capillaries essential to satisfactory operation. Burn out driers will also have to be fitted following compressor motor burn out.
Evaporator freeze fracture
When the evaporator within a water chiller is fractured due to freezing, the water enters the refrigeration system, passing first through the compressor, very often passing through the condenser, liquid receiver and liquid line. This oil and water mixture must be removed completely in order to bring the system to satisfactory operation and ensuring the new compressor(s) will not fail. Where water has entered the system due to evaporator failure, engineers may have to apply vacuum pumps to remove all traces of water from within the system over a period of many weeks, repeatedly changing vacuum pump oil and applying new filters OR driers. The reason that dehydration via vacuum pumps will take so long is due to residual liquid water literally freezing at various points in the system. Once frozen, it is no longer possible to rapidly remove the water as vapour.
The good old-fashioned approach 22 April 2019
www.acr-news.com
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