FEATURE
WATER TREATMENT AND
WASTE MANAGEMENT
“Prevention is better than cure, so when
it comes to working on a new installation,
fi tting a deaerator straight out the gate is
ultimately the best option”
Clearing the air on deaeration
With deaeration rapidly emerging as a crucial tool for
maintaining heating system effi ciency, some questions still
remain around what exactly a deaerator does, and how. Kevan
Peaker, UK business unit director at Spirotech, answers the
most commonly asked questions and explains how deaeration
can overcome many heating system complaints.
While deaeration is already
widely adopted by heating
professionals across Europe,
interest in deaerators has
signifi cantly increased among installers in
the UK over recent years.
As heating engineers become more
aware of the damaging impact air can
have on a heating system, there are a few
key areas to be clued up on before you
recommend this effi ciency improving
measure to homeowners.
HOW DO I IDENTIFY THE PRESENCE
OF AIR?
All water contains free air, microbubbles
and dissolved gases, namely nitrogen and
oxygen. Similar to when you boil a kettle
or open a bottle of fi zzy drink, dissolved
gases will become liberated from the
water and form microbubbles when there
is either an increase in temperature, or a
decrease in pressure.
This can be hugely problematic in a
heating system, and there are several signs
to look out for that indicate the presence
of air.
A high volume of magnetite is actually
one of the main indicators. Untreated
microbubbles will eventually be
reabsorbed into the system water, where
the oxygen will react with any ferrous
internal surfaces and gradually corrode
the system.
Magnetite can only form when air,
metal and water are present, and it is this
corrosion process that leads to a build-up
of magnetite debris, which will eventually
clog the system and lead to serious
ineffi ciencies.
As a result, system components may fail
earlier than expected and heat output
may be reduced. Noisy radiators, cold
spots and the need for regular manual
venting are other signs to look out for – all
of which add up to an ineffi cient and less
reliable system.
WHAT’S THE
DIFFERENCE BETWEEN
AN AUTOMATIC AIR
VENT (AAV) AND A
DEAERATOR?
Most engineers will be
familiar with an AAV, the
valve fi tted at the top of a
system to release air before
the fi lling or draining
process. It is fi tted at the
as air will naturally rise
upwards and form large
pockets of free air. If left alone, these
pockets of air will lead to signifi cantly
reduced fl ow rate and have a marked
adverse impact on effi ciency levels.
For a long time, it was widely believed
than an AAV alone could overcome
the issue of air within a heating system.
However, while the valve is very useful
during the fi lling or draining process, and
for the ongoing release of free air, it does
little to remove microbubbles.
Microbubbles are so small, and,
therefore, have such a hard surface
tension, that they cannot coalesce to form
a larger bubble that can be released by
the AAV. Instead, without the correct
conditioning, they will remain in a system
and cause ongoing ineffi ciencies.
It’s thanks to the technology in a
deaerator – such as the SpiroVent
RV2 – that the correct environment
can be created for microbubbles to be
successfully expelled.
WHERE DO I FIT A DEAERATOR?
A deaerator should be fi tted on the fl ow
pipe at the point in the system with the
highest temperature and lowest pressure,
as this is where microbubbles will form.
Utilising specialist tube technology,
a deaerator creates the right conditions
for microbubbles to rise upwards out of
the water, before being released by an
An open deaerator showing
the removal of microbubbles
from a heating system
automatic valve at the
top of the unit.
The internal tube cluster
acts as a braking system to
decrease the water velocity,
where, alongside an
integral laminar ‘no-fl ow
zone’, the microbubbles
are able to overcome the
mass fl ow conditions and
automatically rise, instead
of continuing their path
around the system.
DO I STILL NEED
TO FIT A DIRT
SEPARATOR?
Prevention is better than cure, so when
it comes to working on a new installation,
fi tting a deaerator straight out the gate is
ultimately the best option.
Although fi tting a deaerator should go
a long way in ensuring that there won’t be
the environment for magnetite to form,
only with the help of a dirt separator
– such as the SpiroTrap MB3 – that
will capture any other debris that may
enter the system can the highest level of
effi ciency be maintained.
When faced with an older existing
system, it’s best practice to fi t both a dirt
separator and deaerator. If a system hasn’t
been properly protected in the past, it’s
likely that the internal elements will have
already been subject to corrosion, in
which case, a dirt separator will remove
any contaminants from the system.
By fi tting a deaerator alongside this,
installers will be able to offer customers
the peace of mind that their heating
system will be protected from any further
damage in the future.
ENQUIRY NUMBER 108
A deaerator should
be fi tted on the
fl ow pipe of a
heating system
highest point of the system,
40 Heating & Plumbing Monthly | JUNE 2018 | www.hpmmag.com
/www.hpmmag.com
