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14 - STANDARD MAINTENANCE
14.6 - Condenser coil
We recommend, that coils are inspected regularly to check the
degree of fouling. This depends on the environment where the
unit is installed, and will be worse in urban and industrial
installations and near trees that shed their leaves.
For coil cleaning, two maintenance levels are used, based on the
AFNOR X60-010 standard:
14.6.1 - Level 1
14.6.1.1 - Recommendations for maintenance and
cleaning of round tube plate fin (RTPF) 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.
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 corrosion
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.
14.6.1.2 - 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.
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- 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.
14.6.2 - Level 2
- Proceed to level 1
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.
14.7 - Evaporator maintenance
Check that:
- The insulating foam is intact and securely in place.
- The cooler heaters are operating, secure and correctly
positioned.
- The water-side connections are clean and show no sign of
leakage.
14.8 - Compressor maintenance
14.8.1 - Oil separator
Check the correct operation of the heaters and check that they
are well attached to the oil separator ring.
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