Thermo Pride CHB1-50N Installation And Operation Manual page 34

All installations and services must be performed by qualified service personnel.
3. USE OF NON-THERMO PRIDE FILTER RETENTION MEANS
If a method other than the Thermo Pride filter rack is selected for retention of the filter and/or use of a
different filter type is desired, see Table 3 for minimum size guidelines for selecting a filter system for the
CHB1 or CDB1 furnaces.
MINIMUM FILTER AREA REQUIRED (LENGTH X WIDTH, SQ. IN.)
FILTER TYPE
*THERMO
PRODUCTS
SUPPLIED
PERMANENT FILTER
STANDARD
PERMANENT FILTER
DISPOSABLE TYPE
FILTER
* The Thermo Products supplied filter can be cut to size to fit other filter retention systems as long as the
minimum size requirement is met. NOTICE: Any internal stiffeners used in the filter must not be removed,
although they can be cut to size as needed.
NOTICE: The filter areas in table 3 are the minimum areas required based on the CFM generated by the
furnace for standard heating speeds only. The following formula can be used to determine the minimum
filter area required for cooling if the unit is equipped with cooling. This value should then be compared to
the value shown in table 3 and the larger of the two should then be used for determining the minimum filter
area required for that installation.
MAXIMUM
RATE
AIR
VELOCITY
CHB1,CDB1-
50
600 FT./MIN. 172 IN.
500 FT./MIN. 208 IN.
300 FT./MIN. 344 IN.
Figure 20
TABLE 3
REQUIRED CFM/(FILTER VELOCITY RATING X 144)=
FILTER (IN
FURNACE MODEL
CHB1,CDB1-
75
2 * 2*
254 IN.
2 2
304 IN.
2 2
506 IN.
28
2
)
CHB1,CDB1- CHB1,CDB1-
100
2*
328 IN. 402 IN.
2
394 IN. 484 IN.
2
656 IN. 804 IN.
125
2*
2
2