Daikin DFG Series Installation Instructions Manual page 23

Prior to servicing MCHE, be sure to disconnect the power
supply and use lock-out methods to prevent the power from
accidentally being turned on.
Shut Down Periods
During periods when the MCHE is not operated for longer than a
week, the MCHE must be completely cleaned following the clean-
ing procedure. This practice must also be performed during short
shut-down periods where corrosive deposits accumulate on the
MCHE.
Cleaning Procedure
Relative to tube & fin heat exchangers, MicroChannel heat ex-
changer coils tend to accumulate more dirt on the surface of the
coil and less dirt inside the coil, making them easier to clean. Fol-
low the steps below for proper cleaning:
STEP 1: Remove Surface Debris
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 noz-
zle, etc.
STEP 2: Rinse
Rinse the coil by following procedure:
1. Rinse the coil by approved MCHE cleaner first, or rinsing
by water directly;
2. Waiting for 5 minutes;
3. Wash the coil by water;
Adjust the angle of gimbaled nozzle and insert it through
fans. Using an extension rod if the nozzle cannot reach
the bottom side. Preferably cleaning the coils from the
inside-out and top to bottom (see figure 1), running the
water through every fin passage until it comes out clean.
The fins of MicroChannel coils are stronger than tradi-
tional tube & fin coil fins but still need to be handled with
care. Do not hit the coil with the hose. We recommend
placing your thumb over the end of the hose to obtain a
gentler spray and reduce the possibility of impact dam-
age. Please PAY MORE ATTENTION when using a pressure
cleaning equipment to prevent damage.
CAUTION
FIGURE 1
Highest pressure of cleaning equipment shall not exceed 15 bar,
and tentatively move the cleaning equipment from far to near to
prevent damage.
• KEEP the outlet of washer away from coil for at least 4in
(see figure 2);
• KEEP the water gun perpendicular to the coil surface and
the angle error shall less than 20°, or ±40° if the distance
from washer to coil is more than 12in (see figure 2);
• Water outlet angle for high pressure cleaning equipment
shall over 15° (see figure 3).
Warranty claims related to cleaning damage, especially for incor-
rect pressure washing operation, or corrosion resulting from ap-
plying non-recommended cleaners, will NOT be honored.
STEP 3: Remove Surface Debris
Depending on the installation and fin geometry, MicroChannel
heat exchangers could possibly retain more water compared to
traditional tube & fin coils. It is advised to blow off or vacuum out
the residual water from the coil to speed up drying and prevent
pooling. Daikin recommends a quarterly cleaning of the coils, as
the minimum. The cleaning frequency should be increased de-
pending on the level of dirt/dust accumulation and the environ-
ment (e.g., coastal areas with chlorides and salts) or industrial
areas with aggressive substances.
Field applied coatings are not recommended for brazed alu-
minum MicroChannel heat exchangers. MicroChannel heat
exchangers must NOT be coated using any other coating,
Coating of a coil using a supplier or coating process is not
approved and is not covered by the product warranty. It
may also reduce the lifetime and/or the performance of the
MicroChannel heat exchanger.
23
FIGURE 2
FIGURE 3
WARNING