HVAC – COIL & FILTER CLEANING
A spotless, well-maintained HVAC
system not only reduces overheads,
but also conserves natural resources
by reducing energy and water
consumption
A clean start
By Ian Vallely
Air conditioning and heating
account for around half of all
operating costs in a typical
commercial building and
that makes dirty, ineffi cient
systems eye-wateringly expensive to
operate. Eff ective coil maintenance
(including regular fi lter replacement) is one
of the simplest yet most eff ective ways of
improving HVAC system effi ciency.
As Richard Betts, MD of Rabscreen,
explains, HVAC coils work on the principle
that the fi ns attached to the refrigerant
pipework receive unrestricted cooling air to
reduce the temperature of the refrigerant:
“The greater the surface area of the fi ns,
the higher the effi ciency of cooling. When
dirty, there is a thermal blanket over the
fi n. A 1mm layer of dust will reduce the
effi ciency of the coil by 21% and increase
the energy used by up to 30%.”
Frank Intrieri (pictured, inset) is
vice president of sales for Goodway
Technologies, a sister company to
SpeedClean, a manufacturer of HVAC
maintenance tools. He agrees that airfl ow
is greatly diminished if coils and fi ns are
not cleaned regularly: “The HVAC unit
is going to run ineffi ciently, so it will
work harder and may struggle
to get to the temperatures
required. Electrical bills are
going to increase, and the
system will break down more
frequently.”
However, as Andy
Harvey, marketing manager
of Advanced Engineering, points
out, not all coil cleaning solutions
are created equal: “While there are a wide
range of cleaning options available, some
are better than others. We’re aware of
some products that leave coils appearing
clean and shiny. But, on closer inspection,
the chemical has etched onto the coils,
damaging them and reducing their
effi cacy.”
VARIED CLEANING
Indeed, there are a variety of ways to
clean coils and they vary enormously
in eff ectiveness, warns Intrieri: “Some
applications can combine water and
chemicals, some of which are harsh or high
acidity, and those can also do damage,
eating away at the aluminium fi ns on a
HVAC coil. Ideally, if you are going to use
a chemical, use a biodegradable, nonacidic
alkaline-based one.”
Intrieri’s company off ers
cleaning products for low
pressure cleaning using
a self-advancing foam
cleaning chemical. This
expands deep into the
coil beds and, as it does so,
it dislodges dirt and debris
trapped between the fi ns: “Instead of
pushing the dirt and debris into the coil and
embedding it deeper, we try to push it from
the inside out.”
However, chemical cleaning is not the
only way to keep HVAC coils in pristine
condition. Another way is to employ ‘Active
Field Technology’ (AFT). Coils provide
a breeding ground for mould, bacteria
and viruses, which can cause operational
issues, potential litigation and, in certain
severe cases, loss of life.
Microbial build-up on the heat exchange
plates and drain pans of the cooling coils
18 www.operationsengineer.org.uk May 2019
/www.operationsengineer.org.uk