Unit Size
Table 7 - Cooling 4 and Heating Air Delivery - CFM (Bottom Return 5 with Filter) (Continued)
Switch Settings External Static Pressure (ESP)
SWx-1
CF Default: OFF See note 4
OFF ON 745 705 680 See note 4
OFF OFF 925 900 885 See note 4
OFF ON 1100 1105 1085 See note 4
Cooling (SW2) ....
ON OFF 1255 1280 1275 1285 I 1270 1260 1250 1230
Cont Fan
(SW3) ....
ON ON 1455 1465 1465 1470 I 1455 1450 1435 1415
ON OFF 1855 1855 1850 1830 I 1805 1775 1750 1730
ON ON 2200 2190 2185 2170 I 2145 2085 1990 1890
CIg SW2: Maximum CIg Airflow 2
Heating
(SWl)
Low Heat Airflow 3
_. Set SW1-5 to ON for nominal 400 CFM/ton (+15% airflow).
Set SW4-3 to ON for nominal 325 CFM/ton (-7% airflow).
Set both SW1-5 and SW4-3 to ON for nominal 370 CFM/ton (+7% airflow).
The above adjustments in airflow are subject to motor horsepower range/capacity.
2. Maximum cooling airflow is achieved when switches SW2-1, SW2-2, SW2-3 and SW1-5 are set to ON, and SW4-3 is set to OFF.
3. All heating CFM's are when low heat rise adjustment switch (SW1-3) and comfort/efficiency adjustment switch (SW1-4) are both set to OFF.
4. Ductwork must be sized for high-heating CFM within the operational range of ESP. Operation within the blank areas of the chart is not re-
commended because high-heat operation will be above 1.0 ESP.
5. All airflows on 21" (533 mm)casing size furnaces are 5% less on side return only installations.
6. Side returns for 24.5" (622 mm)casing sizes require two sides, or side and bottom, to allow sufficient airflow at the return of the furnace.
7. Airflows over 1800 CFM require bottom return, two-side return, or bottom and side return; otherwise excessive watt draws may result. A
minimum filter size of 20" x 25" (508 x 635 mm) is required.
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