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CLEANING THE COIL
1 - Remove the coil from the cabinet or plenum, and
take the coil to an appropriate place to clean it.
2 -
Vacuum or brush the coil to remove matted
and surface debris from the fins. Use vacuum
attachments and /or brushes that are non-
destructive to fins.
3 - If oil deposits are present, spray the coil with a mild
coil cleaner with a pH in the range of 5 to 9 to soften
deposits. Do not leave the coil cleaner on the coil
for more than 10 minutes. Flush the coil thoroughly
with potable water.
4 - Spray the coil at a vertical angle of 30 to 45 degrees
with a constant stream of water at moderate
pressure. A pressure washer with a fan nozzle will
work best. Do not spray the coil from a horizontal
direction.
5 - Direct the spray so that any debris is washed out of
the coil. For most residential units, hot water is not
necessary.
NOTE -
Attempting to back flush from the inside of the coil
will require removing parts from the unit, and it may be
very difficult to flush the whole coil surface. Attempting to
blow water through a coil will slow the water stream and
reduce the flushing action of the outer fin surface.
6 - Replace the coil into the cabinet or plenum. Ensure
that you have followed the proper procedure for
routing and securing the refrigerant tubing.
IMPORTANT
Ensure that the distributor lines are not rubbing together
or kinked. All tubes must have enough clearance
from other metal parts. Use wire ties to secure tubes
to prevent movement that could cause the refrigerant
tubing to fail.
6 -
When the required draft gauge readings are
obtained, remove the draft gauge lines and insert
snaphole plugs into the test holes.
TABLE 2. Air Volume / Static Pressure Drop Across Coil
Cabinet
Vol: CFM
Drop: in. w.g.
CHX35
Model
Width in.
Dry
Wet
-18A-2F
14-1/2
600
.09
.11
-24A-2F
-24B-2F
14-1/2
17-1/2
800
800
.15
.09
.19
.11
-30A-2F
-30B-2F
14-1/2
17-1/2
1000
1000
.24
.14
.27
.16
-36A-2F
-36B-2F
-36C-F
14-1/2
17-1/2
21
1200
1200
1200
.30
.16
.15
.39
.21
.18
-42B-2F
-42C-2F
14-1/2
17-1/2
1400
1400
.26
.18
.31
.21
-48B-2F
17-1/2
1400
.25
.29
-48C-2F
21
1600
.27
.30
-51C-2F
21
1600
.25
.29
-60D-2F
24-1/2
2000
.24
.30
Maintenance
NOTICE !
Failure to follow instructions will cause damage to
the unit.
This unit is equipped with an aluminum coil. Alu-
minum coils may be damaged by exposure to solu-
tions with a pH below 5 or above 9. The aluminum
coil should be cleaned using potable water at a mod-
erate pressure (less than 50psi). If the coil cannot
be cleaned using water alone, Lennox recommends
use of a coil cleaner with a pH in the range of 5 to 9.
The coil must be rinsed thoroughly after cleaning.
A trained technician or service agency must perform main-
tenance and service on equipment. At the beginning of
each heating or cooling season, indoor coils should be
inspected to determine whether the coil requires cleaning.
