25
AIR FILTER - UPFLOW FURNACES
To remove the external upflow filter from the external filter
rack, disconnect electrical power to the furnace and follow
the directions provided with the external filter rack kit.
NOTE:
If using Media Air Cleaner MAC1 or Electronic Air
Cleaner EAC5, follow the directions that came with the air
cleaner for proper filter removal, cleaning, and replacement
procedures.
Replace the filter with the same type and size filter when
needed.
Remove the two front panels (louvered panel first). Using
a vacuum cleaner, clean out the air circulation blower area,
external filter rack or air cleaner area, and the adjacent area
of the return air duct.
Clean, wash and dry a permanent filter. If using a media air
cleaner (MAC1) or electronic air cleaner (EAC5), follow
instructions provided with air cleaner for proper cleaning/
replacement procedures. If using a metal filter, spray both
sides with a dust adhesive as recommended on adhesive
container. Spray adhesives for use with permanent metal
filters can be found at most hardware stores. To reinstall
filter follow installation instructions for the external filter
rack or air cleaner. BE SURE AIRFLOW DIRECTION
ARROW POINTS TOWARDS THE BLOWER.
When the filter is located in the bottom of the furnace on a
bottom return system the filter is held in place by a wire filter
retainer. To change and clean the filter, push back and up
on the wire filter retainer to release it from under the front lip
of the basepan. Slide the filter out and follow cleaning or
replacement instructions above. Replace filter opposite of
removal.
Front of Furnace
Blower
Grab Here
And Lift
F
ilt
e
r
Front of Furnace
Blower
1. Lift filter above bottom
2. Tilt filter to clear rail.
rail.
Front of Furnace
Blower
Front of Furnace
Blower
3. Lower filter below top
4. Pull filter out.
rail.
Figure 37
Filter Removal
AIR FILTER - COUNTERFLOW FURNACES
A furnace mounted filter rack, shipped with the furnace, can
be used in a counterflow installation.
The furnace-mounted filter rack
includes a rack mounted
on the top of the furnace. Two filters fit into the rack and rest
against the sides of the return air plenum, forming a “V”
above the furnace.
The filters should be inspected frequently and cleaned or
replaced when necessary. If using a media air cleaner
(MAC1) or electronic air cleaner (EAC5), follow instructions
provided with air cleaner for cleaning/replacement proce-
dures of filter. In some installations, the filters can be
inspected after disconnecting the electrical power and
removing the optional access door in the return air plenum.
If this access panel is not present, proceed as follows:
1. Disconnect the electrical power.
2. Remove the non-louvered door from the furnace.
3. Remove the left filter by reaching to the left side of the
blower, pushing the filter up slightly to remove it from
the filter rack, and pulling it down to the left of the air
circulation blower and out the air circulation blower
door. Repeat with the right filter.
4a. Dirty throwaway filters must be replaced with the same
filter type and size.
4b. Dirty permanent metal filters must be cleaned as fol-
lows:
Wash, rinse, and dry the permanent filters. Both sides
should then be sprayed with a filter adhesive as is
recommended on the adhesive container. Many hard-
ware stores stock spray adhesives for use with perma-
nent filters.
If badly torn or not able to be cleaned, these filters must
be replaced by equal size permanent, high velocity
filters. Throwaway filters must not be used as replace-
ment for permanent filters. Under normal use, perma-
nent filters should last for several years.
5. To reinstall the filters, first MAKE CERTAIN THE
AIRFLOW DIRECTION ARROW POINTS TOWARDS
THE FURNACE. Then insert the filters from the left
side of the blower. Starting with the right filter, push the
filter into the plenum so that the bottom of the filter rests
in the filter rack and the upper edge rests against the
side of the plenum. Repeat with the left filter (Figure
38).
6. Replace the air circulation blower door, then reconnect
the electrical power.
