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Removal of fibres that obstruct the surfaces
Fibres and dirt collected on the coil surface must be removed
with a vacuum cleaner. If you do not have a vacuum cleaner,
a soft brush with non-metallic bristles can be used instead.
In all cases cleaning must be done in the direction of the fins,
as the coil surface is easily damaged. The fins bend easily
and damage the protective coating of the coil, if cleaning is
done at right angles to the fins. Clean against the air flow
direction.
NOTE: Using a water jet from a spray hose on a polluted
surface will result in fibres and dirt becoming trapped in the
coil, making cleaning more difficult. All fibres and dirt must
be removed from the surface, before using a low-speed
rinsing jet.
Periodical cleaning with clean water:
For coils installed in a coastal or industrial environment
periodical cleaning by rinsing with water is beneficial. It
is however essential that rinsing is done with a low-speed
water jet to avoid damaging the fins. Monthly cleaning as
described below is recommended.
ATTENTION
•
Chemical cleaning agents, water containing bleach,
acidic or basic cleaning agents must never be used to
clean the coil exterior or interior. These cleaning agents
may be difficult to rinse off and can accelerate corro-
sion at the joint between tube and fins, where two
different materials come into contact.
•
High-speed water from a high-pressure cleaner, spray
hose or compressed air cleaner must never be used for
coil cleaning. The force of the water or air jet will
bend the fins and increase the air-side pressure drop.
This can result in reduced performance or nuisance
shutdowns of the unit.
13.6.1.2 - Recommendations for maintenance and cleaning
of MCHE (microchannel) condenser coils
•
Regular cleaning of the coil surface is essential for
correct unit operation. Eliminating contamination and
removal of harmful residue will increase the operating
life of the coils and the unit.
•
The maintenance and cleaning procedures below are
part of the regular maintenance and will prolong the
life of the coils.
ATTENTION: Do not use chemical cleaners on MCHE
condenser coils. These cleaning agents can accelerate
corrosion and damage the coils.
•
Remove foreign objects and debris attached to the
coil surface or wedged between the chassis and the
supports.
•
Provide personal protection equipment including
safety glasses and/or a face mask, waterproof clothing
and safety gloves. It is recommended to wear clothing
that covers the whole body.
•
Start the high-pressure spray gun and remove any
soap or industrial cleaner from it before cleaning the
condenser coils. Only drinkable cleaning water is
permitted to clean the condenser coils.
•
Clean the condenser face by spraying the coil evenly
und in a stable manner from bottom to top, directing
the water jet at right angles to the coil. Do not exceed
6200 kPa (62 bar) or an angle of 45° related to the
coil. The diffuser must be at least 300 mm away from
the coil surface. It is essential to control the pressure
and to be careful not to damage the fins.
ATTENTION: Excessive water pressure can break the weld
points between the fins and the flat MCHE microchannel
tubes.
13.6.2 - Level 2
Clean the coil, using appropriate products. We recommend
cleaning with clear water to remove pollutants. If the use
of cleaning products is necessary, we specify:
•
pH between 7 and 8
•
Absence of chlorine, sulphate, copper, iron, nickel or
titanium
•
Chemical compatibility with aluminium and copper.
For RTPF coils this process can either be carried out using
a high-pressure spray gun in the low-pressure position. With
pressurised cleaning methods care should be taken not to
damage the coil fins.
The spraying of the coil must be done:
•
In the direction of the fins
•
In the opposite direction of the air flow direction
•
With a large diffuser (25-30°)
•
At a minimum distance of 300 mm from the coil.
It is not necessary to rinse the coil, as the products used
are pH neutral. To ensure that the coil is perfectly clean, we
recommend rinsing with a low water flow rate.
For MCHE condenser coils refer to chapter 13.6.1.2 under
level 1 maintenance for use of a high-presssure spray gun.
IMPORTANT:
•
Never use pressurised water without a large diffuser. Do
not use high-pressure cleaners for Cu/Cu and Cu/Al
coils! High pressure cleaners are only permitted for
MCHE coils (maximum permitted pressure 6200 kPa
(62 bar).
•
Concentrated and/or rotating water jets are strictly
forbidden.
•
Never use a fluid with a temperature above 45 °C to
clean the air heat exchangers.
•
Correct and frequent cleaning (approximately every
three months) will prevent 2/3 of the corrosion
problems.
•
Protect the control box during cleaning operations.
51
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