Filter
Top Products
All installations and services must be performed by qualified service personnel.
12
NOTICE: This furnace has been shipped from the factory with a permanently lubricated
circulating air blower motor. Any maintenance to this blower motor is to be performed only by a
qualified heating contractor.
B. FILTER MAINTENANCE PROCEDURE
1. The return air filter provided with this unit is a re-useable type filter. This filter should be
inspected monthly. When dirty, the filter must be cleaned or replaced, if necessary, to assure
proper furnace operation. Follow the cleaning, removal and replacement procedure below.
NOTICE: If the furnace is installed in a home or structure being remodeled, dust levels may be
much higher than normal The filter must be inspected daily and cleaned as needed until dusty
conditions have been eliminated. Any replacement motors not obtained through Thermo
Products should be lubricated according to the motor name plate.
: This furnace is not to be used for temporary heating of buildings or structures under
construction.
UPFLOW FURNACE (CHX1/CHB1/MHA1)
The filter rack or drop chute will be located between the return air plenum and the return air
opening of the furnace (See Figure 3). Slide dirty filter out of the filter rack. Clean the filter by
vacuuming, rinsing with tap water, hosing or dipping in an ordinary detergent solution. Replace
the completely dry filter in the rack. The mesh side of the filter must be installed towards the
furnace after cleaning.
COUNTERFLOW FURNACE (CDX1/CDB1/MDA1)
TURN OFF POWER TO FURNACE. The filter rack will be located on top of the furnace
inside the return air duct using either a V-rack or a drop chute similar to one shown for the CHX1
in Figure 3. To change filter with a front load type drop chute, follow the instructions for an
upflow furnace. To change filters using the V-rack, remove the furnace front door and remove
the filters through the blower opening (or in the event access slots are provided in the plenum,
pull the filters directly out through these slots). Clean filters by vacuuming, tap water rinsing,
hosing or dipping in an ordinary detergent solution. After cleaning, replace completely dry filter,
mesh side down on the filter rack on the top of the furnace. Replace front door. Turn on power to
furnace.