Thermo Pride CLQS1-050T36N Installation And Operation Manual page 41

All installations and services must be performed by qualified service personnel.
MINIMUM FILTER AREA REQUIRED (LENGTH X WIDTH)
FILTER TYPE
THERMO PRIDE *
SUPPLIED
PERMANENT
FILTER
STANDARD
PERMANENT
FILTER
DISPOSABLE
TYPE
FILTER
* The Thermo Pride 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.
FORMULA:
(tons of cooling) x (400 CFM per ton) x (144 square inches per foot) = filter area in sq.inches
(max. rated velocity of filter from Table 3 for the filter type)
EXAMPLE:
If you have a CLQS1-100 furnace with 4 tons of cooling and a standard permanent filter.
4 tons x 400 CFM x 144 = 460 square inches for cooling
500 fpm
For heating, a CLQS1-100 needs 422 square inches of filter. The filter system must be designed for the
larger CFM requirement determined for cooling of 460 square inches. A filter would have to be sized so
that the area (length X width) was at least 460 sq. in.
MAX. EQUATION: REQUIRED CFM / MAX. RATED
RATED VELOCITY X 144 = FILTER AREA (IN
VELOCIT HEATING VALUES PROVIDED IN CHART
Y
-050
600 176 IN
FT/MIN
500 211 IN
FT/MIN
300 352 IN
FT/MIN
BELOW
-075
2 2
264 IN
2 2
317 IN
2 2
528 IN
TABLE 3
39
2
)
-100 -125
2
352 IN 440 IN
2
422 IN 528 IN
2
704 IN 880 IN
2
2
2