11
Counterflow Filters (Not Included With Furnace)
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.
FILT
ER
FILTER
ACCESS
DOOR
RETURN
DUCT
FI
LT
ER
Counterflow Furnace Mounted Filter Rack
Remember dirty filters are the most common cause of
inadequate heating or cooling performance.
The filters should be inspected and cleaned or changed
every two months or as required. In some installations,
the filters can be inspected and cleaned or changed after
disconnecting the electrical power and removing the
optional access door in the return air plenum. If the
installation does not have an access door proceed as
follows:
1. Disconnect the electrical power.
2. Remove the upper door from the furnace.
3. Remove the left filter first by reaching to the left side of
the blower, pushing the filter up slightly to remove it
from the filter rack. Then carefully pull the filter down
past the left side of the blower housing. Be careful not
to dislodge any trapped dirt or debris from the filter.
4. Remove the right filter by reaching to the left side of
the blower. Lift filter up slightly to remove it from the fil-
ter rack. Move the filter to the left side of the return air
plenum, and down past the left side of the blower
housing. Be careful not to dislodge any trapped dirt or
debris from the filter.
a. Some installations will have two throwaway filters.
If dirty, these filters must be thrown away and
replaced with two new similar size throwaway
filters.
b. Other installations will have two permanent filters.
Wash, rinse and dry dirty permanent filters. After
cleaning, both sides should be sprayed with a filter
adhesive (available in hardware stores) as in-
structed on the adhesive container.
When badly torn or uncleanable, permanent filters
must be replaced with permanent filters of the
same type and size.
Routine Maintenance
5. To reinstall the filters, first MAKE CERTAIN THE AIR-
FLOW 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
8).
6. Replace the air circulation blower door, then reconnect
the electrical power.
Horizontal Filters (Not Included With Furnace)
For furnaces installed horizontally, filters must be in-
stalled external to the furnace casing. A central return
with filters installed in the duct behind the return grille
may be used. This would simplify filter replacement by
merely requiring the removal of the grille. Clean or replace
filters every two months or as required. Dirty filters are the
most common cause of inadequate heating or cooling
performance.
Induced Draft Motor Lubrication
The induced draft motor bearings are permanently lubri-
cated. No further lubrication is required.
Air Circulating Blower Motor Lubrication
The air circulation blower motor bearings are permanently
lubricated. No further lubrication is required.
