Bryant 986TB Installation, Start-Up, Operating And Service And Maintenance Instructions page 34

Table 9 − AC
Unit Size AC/CF Switch Settings
SWx­3 SWx­2
66120
AC Default:
OFF OFF
CF Default:
OFF OFF
OFF OFF
OFF ON
OFF ON
AC (SW2)
ON OFF
CF (SW3)
ON OFF
ON ON
ON ON
AC SW2:
Maximum Clg Airflow
High Heat Airflow
Heating
(SW1)
Low Heat Airflow
Set SW1­5 to ON for nominal 400 CFM/ton (+15% airflow).
1.
Set SW4­3 to ON for nominal 325 CFM/ton (­7% airflow).
Set both SW1­5 and SW4­3 to ON for nominal 370 CFM/ton (+7% airflow).
The above adjustments in airflow are subject to motor horsepower range/capacity.
Maximum cooling airflow is achieved when switches SW2­1, SW2­2, SW2­3 and SW1­5 are set to ON, and SW4­3 is set to OFF.
2.
All heating CFM's are when low heat rise adjustment switch (SW1­3) and comfort/efficiency adjustment switch (SW1­4) are both set to OFF.
3.
Ductwork must be sized for high­heating CFM within the operational range of ESP. Operation within the blank areas of the chart is not re­
4.
commended because high­heat operation will be above 1.0 ESP.
All airflows on 21" (533 mm) casing size furnaces are 5% less on side return only installations.
5.
Return air above 1800 CFM on 24.5" (622 mm) casing sizes requires two sides, one side and bottom, or bottom only to allow sufficient air­
6.
flow to the furnace.
Airflows over 1800 CFM require bottom return, two­side return, or bottom and side return; otherwise excessive watt draws may result. A
7.
minimum filter size of 20" x 25" (508 x 635 mm) is required.
4
and Heating Air Delivery − CFM (Bottom Return
SWx­1 0.1 0.2
OFF 1850 1855
OFF 930 925
ON 765 745
OFF 930 925
ON 1095 1100
OFF 1265 1255
ON 1465 1455
OFF 1850 1855
ON 2200 2200
2
2200 2200
3
1815 1820
3
1640 1640
5
with Filter) (Continued)
External Static Pressure (ESP)
0.3 0.4 0.5 0.6
1860 1855 1850 1830
915 900 885
740 705 680
915 900 885
1110 1105 1085
1265 1280 1275 1285
1470 1465 1465 1470
1860 1855 1850 1830
2200 2190 2185 2170
2200 2190 2185 2170
1825 1820 1815 1795
1645 1650 1645 1645
34
0.7 0.8 0.9 1.0
1805 1775 1750 1730
See note 4
See note 4
See note 4
See note 4
1270 1260 1250 1230
1455 1450 1435 1415
1805 1775 1750 1730
2145 2085 1990 1890
2145 2085 1990 1890
1775 1745 1720 1700
1630 1620 1600 1580