69
DISCONNECT MAIN ELECTRICAL
POWER TO THE UNIT BEFORE
ATTEMPTING ANY MAINTE-
NANCE. FAILURE TO DO SO CAN
CAUSE ELECTRICAL SHOCK
RESULTING IN PERSONAL
INJURY OR DEATH.
FILTERS
Keep the filters clean at all times.
Remove the filter. Vacuum dirt from filter,
wash with detergent and water, air dry
thoroughly and reinstall.
NOTE: Some filters must be resized to fit
certain units and applications. See Table
22 and Figures 47, 48 & 49.
1. 21" - 90,000 & 105,000 BTUH units
require removal of a 3
1
/
2
-in. segment
of filter and frame to get the proper
width for a side filter.
2. 24
1
/
2
" - 120,000 BTUH unit requires
removal of a 7" segment of filter and
frame to get the proper width for a
side filter.
!
WARNING
TABLE 22
FILTER SIZES
UPFLOW FILTER SIZES
FURNACE
INPUT
BOTTOM
SIDE
QUANTITY
WIDTH
KBTUH
SIZE
SIZE
17
1
/2"
60 AND 75
15
3
/4" X 25"
15
3
/4" X 25"
1
21"
90 AND 105
19
1
/4" X 25"
15
3
/4" X 25"
1
24
1
/2"
120
22
3
/4" X 25"
15
3
/4" X 25"
1
FIGURE 48
RESIZING FILTERS AND FRAME
MAINTENANCE
FIGURE 47
UPFLOW — FILTER REPLACEMENT
REMOVE SEGMENT TO SIZE
AS REQUIRED
54-24094-01
ADS-5422-01
FILTER MAINTENANCE
Instruct the user or homeowner on
how to access the filters for regular
maintenance.
Filter application and maintenance
are critical to airflow, which may
affect the heating and cooling system
performance. Reduced airflow can
shorten the life of the system’s major
components, such as motor, limits,
heat exchanger, evaporator coil or
compressor. Consequently, it is rec-
ommended that the return air duct
system have only one filter location.
The most common location will be
inside the furnace or a filter base.
Systems with a return-air filter grille
or multiple filter grilles, can have a fil-
ter installed at each of the return-air
openings. Installers are instructed to
show the homeowner or end user
where the filter has been installed.
If high efficiency filters or electronic
air cleaners are used in the system, it
is important that the airflow is not
reduced in order to maximize system
performance and life. Always verify
that the system’s airflow is not
impaired by the filtering system that
has been installed. This can be done
by performing a temperature rise and
temperature drop test.
Instruct the homeowner or end-user
to keep the filter(s) clean at all times.
Instruct them to vacuum dirt from the
filter, wash with detergent and water,
air dry thoroughly and reinstall.
The installer may install a return-air
filter in place of the furnace filter.
DO NOT DOUBLE-FILTER THE
RETURN-AIR DUCT SYSTEM. DO
NOT FILTER THE SUPPLY AIR
DUCT SYSTEM.
