38 www. refrigerationandaircon. co. za RACA Journal I February 2026
MICROCHANNEL HEAT EXCHANGERS voices
Since the inception of the microchannel product, the South African HVAC sector has experienced a substantial number of failures, to the extent that some engineers are prohibiting their use, opting for the well-tried fin-on-tube arrangement to safeguard the client and end-user. Over several years, the type of failure experienced has been – in most cases – refrigerant leakage, leading to premature high repair cost or replacement implications, bearing in mind that the operational life of a heat exchanger is expected to be between 20 and 30 years.
MAINTENANCE OF MCHES In order to achieve an acceptable service lifespan, it is necessary to understand the need for proper routine maintenance. With an MCHE, a more intensive maintenance approach is necessary, something that is not fully understood in the local service industry.
The southern African market presents unique challenges for the implementation and maintenance of MCHEs. These require carefully planned maintenance programmes – crucial in ensuring their longevity and ongoing performance.
Regular cleaning( monthly) with good quality mains water to prevent fouling is essential. The need for high quality cleaning water to prevent scaling and corrosion is paramount. Lowpressure air or( clean) water can be used to remove dust and debris, so as not to damage the fins, the emphasis being on low-pressure.
Routine inspections for refrigerant leaks are important. Refrigerant oil-leak residue at the headers and manifolds or on the face of the heat exchanger, are the tell-tale signs, giving timeous indication of a positive leak, demanding immediate remedial action. In this regard, an accurate field charge is crucial for microchannel coils.
While aluminium has relatively good corrosive resistance, it is extremely vulnerable to salt water, airborne spray and particulate attack. Ongoing high quality protective coating application is absolutely essential over the full life of the chiller.
While expensive, such costings cannot be neglected or ignored. To do so will be tantamount to economic suicide, given the R200 000 price tag for each full heat exchanger panel: in the case of a 12 panel 800kW chiller, this could cost in the order of R2.4-million. By way of comparison, the end-user price of a
38 www. refrigerationandaircon. co. za RACA Journal I February 2026