33
Cooling
4
and Heating Air Delivery -- CFM continued (Bottom Return
5
with Filter)
(SW1---5 and SW4---3 set to OFF, except as indicated. See notes 1 and 2.)
Unit size:
120C24---22
Clg/CF Switch settings
External Static Pressure (ESP)
Clg Switches
SW2---3 SW2---2
SW2---1
Clg Default:
OFF
OFF
OFF
1845
1840
1835
1835
1825
1820
1810
1800
1785
1775
CF Switches
SW3---3 SW3---2
SW3---1
Low---Clg Default:
OFF
OFF
OFF
895
915
915
915
915
See note 4
Cooling Airflow (SW2)
Low---Cooling Airflow
(SW3)
OFF
OFF
ON
715
725
720
710
705
See note 4
OFF
ON
OFF
895
915
915
915
915
See note 4
OFF
ON
ON
1070
1090
1105
1115
1115
1110
1115
1120
1120
1110
ON
OFF
OFF
1240
1265
1280
1295
1295
1305
1305
1305
1315
1315
ON
OFF
ON
1520
1520
1515
1505
1495
1490
1480
1465
1455
1445
ON
ON
OFF
1845
1840
1835
1835
1825
1820
1810
1800
1785
1775
ON
ON
ON
2150
2145
2140
2145
2135
2130
2115
2100
2065
1985
Maximum Clg Airflow
2
2150
2145
2140
2145
2135
2130
2115
2100
2065
1985
CF Switches
SW3---3 SW3---2
SW3---1
Cont. Fan Default:
OFF
OFF
OFF
895
915
915
915
915
See note 4
Continuous Fan Airflow
(SW3)
OFF
OFF
ON
715
725
720
710
705
See note 4
OFF
ON
OFF
805
820
815
810
810
See note 4
OFF
ON
ON
895
915
915
915
915
See note 4
ON
OFF
OFF
895
915
915
915
915
See note 4
ON
OFF
ON
895
915
915
915
915
See note 4
ON
ON
OFF
895
915
915
915
915
See note 4
ON
ON
ON
895
915
915
915
915
See note 4
Heating (SW1)
High Heat Airflow
3
1825
1820
1815
1800
1800
1795
1785
1775
1760
1745
Low Heat Airflow
3
1555
1555
1550
1550
1545
1525
1520
1505
1495
1485
1.
Nominal 350 CFM/ton cooling airflow is delivered with SW1-5 and SW4-3 set to OFF.
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).
This applies to Cooling and Low-Cooling airflows, but does not affect continuous fan airflows.
The above adjustments in airflow are subject ot 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 comfort/efficiency adjustment switch (SW1-4) is 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 rec-
ommended 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.
GAS PIPING
FIRE OR EXPLOSION HAZARD
Failure to follow this warning could result in personal injury,
death, and/or property damage.
Never purge a gas line into a combustion chamber. Never test
for gas leaks with an open flame. Use a commercially available
soap solution made specifically for the detection of leaks to
check all connections. A fire or explosion may result causing
property damage, personal injury or loss of life.
!
WARNING
FIRE OR EXPLOSION HAZARD
Failure to follow this warning could result in personal
injury, death, and/or property damage.
Use proper length of pipe to avoid stress on gas control
manifold and gas valve.
!
WARNING
FIRE OR EXPLOSION HAZARD
Failure to follow this warning could result in personal
injury, death, and/or property damage.
Gas valve inlet and/or inlet pipe must remain capped until
gas supply line is permanently installed to protect the valve
from moisture and debris. Also, install a sediment trap in the
gas supply piping at the inlet to the gas valve.
!
WARNING
Gas piping must be installed in accordance with national and local
codes. Refer to current edition of NFGC in the U.S.A. Refer to
current edition of NSCNGPIC in Canada.
Installations must be made in accordance with all authorities
having jurisdiction. If possible, the gas supply line should be a
separate line running directly from meter to furnace.
NOTE
: Use a back--up wrench on the inlet of the gas valve when
connecting the gas line to the gas valve.
