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8.3 Microchannel Coil Maintenance
Routine cleaning of coil surfaces is essential to maintain proper operation of the unit, avoid corrosion and rusting.
Elimination of contamination and removal of harmful residues will greatly increase the life of the coil and extend the life o f
the unit.
Relative to fin and tube heat exchangers, microchannel coils tend to accumulate more of the dirt on the surface and of the
less dirt inside which can make them easier to clean.
The following maintenance and cleaning procedure are recommended as part of the routine maintenance activities.
1.
Remove surface dirt, leaves, fibers, etc. with a vacuum cleaner (preferably with a brush or other soft attachment rather
than a metal tube), compressed air blown from the inside out, and/or a soft bristle (not wire!) brush. Do not impact or
scrape the coil with the vacuum tube, air nozzle, etc..
NOTE: Use of a water stream, such as a garden hose, against a surface loaded coil will drive the fibers and dirt into the
coil. This will make cleaning efforts more difficult. Surface loaded fibers must be completely removed prior to using low
velocity clean water rinse.
2.
Rinse. Do not use any chemicals (including those advertised as coil cleaners) to wash microchannel heat exchangers.
They can cause corrosion. Rinse only. Hose the MCHE off gently, preferably from the inside out and top to bottom,
running the water through every fin passage until it comes out clean. Microchannels fins are stronger than traditional
tube & fin coil fins but still need to be handled with care.
It is possible to clean a coil with a high pressure washer (max 62 barg) only if a flat shape of the water spray is used
and direction of the spay is kept perpendicular to the fin edge. If this direction is not respected the coil may be destroyed
if using a pressure washer so we do not recommend their use.
NOTE: A monthly clean water rinse is recommended for coils that are applied in coastal or industrial environments to help
to remove chlorides, dirt and debris. It is very important when rinsing, to water temperature is less than 55 °C. An elevated
water temperature (not to exceed 55 °C) will reduce surface tension, increasing the ability to remove chlorides and dirt.
3.
Quarterly cleaning is essential to extend the life of an E-coated coil and is required to maintain warranty coverage.
Failure to clean an E-coated coil will void the warranty and may result in reduced efficiency and durability in the
environment. For routine quarterly cleaning, first clean the coil with an approved coil cleaner. After cleaning the coils
with the approved cleaning agent, use the approved chloride remover to remove soluble salts and revitalize the unit.
NOTE: Harsh chemicals, household bleach or acid cleaners should not be used to clean E -coated coils. These cleaners
can be very difficult to rinse out of the coil and can accelerate corrosion and attack the E -coating. If there is dirt below the
surface of the coil, use the recommended coil cleaners as described above.
Galvanic corrosion of the connection Copper/Aluminum can occurre in corrosive atmosphere under the plastic protection;
during the maintenance operations or periodic cleaning, check the aspect of the plastic protection of the copper/aluminum
connection. If it is inflated, damaged or took off contact the manufacturer representative for advice and information.
9
SERVICE AND LIMITED WARRANTY
All units are factory-tested and guaranteed for 12 months as of the first start-up or 18 months as of delivery.
These units have been developed and constructed according to high quality standards ensuring years of failure -free
operation. It is important, however, to ensure proper and periodical maintenance in accordance with all the procedures
listed in this manual and with good practice of machines maintenance.
We strongly advise stipulating a maintenance contract with a service authorized by the manufacturer in order to ensure
efficient and problem-free service, thanks to the expertise and experience of our personnel.
It must also be taken into consideration that the unit requires maintenance also during the warranty period.
It must be borne in mind that operating the unit in an inappropriate manner, beyond its operating limits or not performing
proper maintenance according to this manual can void the warranty.
Observe the following points in particular, in order to conform to warranty limits:
1.
The unit cannot function beyond the specified limits
2.
The electrical power supply must be within the voltage limits and without voltage harmonics or sudden changes.
3.
The three-phase power supply must not have un unbalance between phases exceeding 3%. The unit must stay turned
off until the electrical problem has been solved.
4.
No safety device, either mechanical, electrical or electronic must be disabled or overridden.
5.
The water used for filling the water circuit must be clean and suitably treated. A mechanical filter must be installed at
the point closest to the evaporator inlet.
6.
Unless there is a specific agreement at the time of ordering, the evaporator water flow rate must never be above 120%
and below 50% of the nominal flow rate.
10
PERIODIC OBLIGATORY CHECKS AND STARTING UP OF APPLIANCES UNDER PRESSURE
The units are included in category I → III of the classification established by the European Directive 2014/68/EU (PED).
For chillers belonging to this category, some local regulations require a periodic inspection by an authorized agency.
Please check with your local requirements.
D–EIMAC01502–18_03EN - 22/25
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