Hot Gas Loop Corrosion?

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Integral chiller cabinets have some apparent advantages over remotes, evaporative drainage is one of them, and using a hot gas loop seems a brilliant idea, but is it?
With many customers finding corrosion on the gas vaporiser pipe in condensate
evaporator trays, it’s logical to assume it’s the cleaning products being used, but is this
true? The same corrosion was found on cabinets less than a year old, that had never
been cleaned, so how can you account for corrosion on copper that has never seen a
cleaning product?
The well documented fact is, condensate water is corrosive to copper. The you add
heat to the equation, constant air exchange, and airborne contaminants, the corrosion is
massively increased.
In light of numerous customers experiencing corrosion on the gas vapouriser pipes
within condensate evaporator trays, it might be tempting to attribute this issue solely to
the cleaning products in use. However, this assumption may not hold true, as instances of
corrosion have been identified in cabinets less than a year old, untouched by cleaning
A crucial factor to consider is the well-established fact that condensate water inherently
possesses corrosive properties towards copper. This raises an essential question: if the
corrosion is occurring in units that have never been exposed to cleaning agents, what
other contributing factors could be at play?
The complexity of this corrosion puzzle becomes clearer when taking into account
additional elements such as the impact of heat, constant air exchange, and the presence
of airborne contaminants. These factors synergistically intensify the corrosive effects on
copper components. Therefore, a comprehensive analysis should go beyond the
assumption of cleaning products as the sole culprit and delve into the broader
environmental conditions affecting the equipment.
In tests carried out at Trinity university on condensate quality, a typical ph was below 6.
Water with a pH below 7 is considered acidic, and acidic conditions can contribute to the
corrosion of copper. Copper is generally corrosion-resistant in neutral or slightly alkaline
environments, but it can corrode in acidic conditions.
The corrosion of copper in acidic water is often influenced by factors such as the acidity
level, the presence of other ions or chemicals, and the duration of exposure. Acidic
conditions can lead to the formation of copper ions and corrosion products, which may
compromise the integrity of the copper material over time.
It’s important to note that the extent of corrosion depends on the specific conditions
and the concentration of acidic substances in the water. If you’re concerned about the
corrosion of copper in a particular environment, testing the water’s pH and considering
other factors that may affect corrosion can provide more accurate information.
Airborne contaminants that can increase the pH of condensate. Some common
airborne contaminants that can increase the pH of condensate include: dust, airborne
particles, cleaning products, perfumes, and local atmospheric conditions such as traffic
or agriculture.
The rate of corrosion of copper in acidic water can be influenced by temperature. In
general, corrosion reactions tend to occur more rapidly at higher temperatures. The
increased kinetic energy of molecules at higher temperatures can enhance the reaction
rates between metal surfaces and corrosive agents present in the water.
Considering that in condensate evaporator trays, the copper refrigerant pipe sits
permanently in acidic water, exacerbated by heat from the gas in the pipe, the cause of
corrosion to the refrigerator pipe in the evaporator tray becomes clear.
Gel-clear tablets are non-corrosive to the soft metals used in HVACR equipment, based
on an antibacterial solution developed form the prevention of biofilm in drinking water
systems, it is the most environmentally friendly condensate drain treatment on the
For more information on this matter, please contact

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