Carrier 48KHA - Manual (Page 15)

Table 6 — Model 48KHA,KLA Air Delivery (cfm)*
at Indicated External Static Pressure and Voltage (cont)
MODEL
48*
UNIT BLOWER
EXTERNAL STATIC PRESSURE (in wg)
VOLTS- MOTOR COILt 208V 230V or 460V
PHASE (60 Hz) SPEED
00 0 1 0 2 0 3 0 4 0.5 0 6 0.7 0,8 0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8
Low
Heat 1440 1435 1425 141$ 1400 1385 1365 1340 1305 1730 1720 1700 1675 1645 1610 1560 1520 1470
Coot 1435 1430 1420 1410 1395 1380 1355 1330 1290 1725 1710 1685 1660 1625 1585 1545 1495 1445
KHA048
208/
Med
Heat 1755 1740 1725 1700 1665 1625 1580 1530 1470 1970 1945 1910 1875 1825 1775 1720 1660 1600
230-3 Cooli 1745 1730 1710 1680 1645 1600 1550 1500 1440 1950 1920 1880 1840 1790 1735 1685 1625 1570
High
Heal 1950 1920 1880 1840 1795 1750 1700 1645 1590 2175 2130 2085 2030 1970 1905 1840 1765 1695
Cool 1925 1890 1850 1810 1765 1715 1665 1615 1560 2130 2085 2035 1980 1920 1855 1790 1720 1650
Low
Heati —
-
_
_
_
-
_ 1610 1600 1580 1560 1530 1495
_
_
230-1
Cool 1595 1585 1575 1550 1515 1475 — - —
High
Heat _
— _
_
_
__
_
— 2375 2280 2185 2095 2000 1905
_ _ _
Coolt — — — — — — — — 2270 2185 2100 2015 1930 1840 — — —
Low
Heat 1880 1875 1860 1825 1770 1700 —
_ _
Cool — — — - - — - - 1875 1865 1840 1790 1725 1650 — — -
KHAO60 230-1 Med
HeatJ
Cool
_
_ _ _ _ _ _ _ _ 2130
207$ 2075
2025 2015
1965
1955
1900 1890
1835 1810
1760 — - —
High
Heal 2345 2260 2180 2095 2010 1930
_ _
Cool: — — - — - - — - 2255 2175 2100 2020 1945 1865 — — —
*Air delivery values are without air filter Deduct field-supplied air filter pressure drop to
obtain external static pressure available for ducting
tHeating airflow values are with a dry coil Cooling airflow values are with a wet coil
iThese airflow values are at the factory heating and cooling blower motor speed setting
A dash {—) indicates portions of the table that are beyond the blower motor capability or
that are not applicable
NOTE. Do not operate the unit at a cooling airflow that is less than 350 fpm per each
12,000 Btuh of rated cooling capacity Indoor coil frosting may occur at airflows below
this point
thermostat is satisfied. When this oceurs, the ther­
mostat switching removes 24-volt control circuit
voltage from gas valve and heating delay relay. Gas
valve closes instantly; however, contacts of de­
energized heating relay remain closed and keep
blower motor running for an additional 2 to 3
minutes. Contacts of heating relay open after 2- to
3-minute delay and blower motor stops. Heating
section is now in a standby condition waiting for
another call for heating from thermostat.
NOTE: The igniter continues to spark for approxi­
mately 10 seconds after burners are ignited.
LIMIT AND PRESSURE SWITCHES — Fur­
nace limit switch (see Eig. 10) closes gas valve if
leaving-air temperature exceeds 175 F.
Normally closed limit switch completes control
circuit through pigtail lead W to gas valve 5 F. See
Fig. 10. Should leaving-air temperature rise to
175 F, switch opens and W control circuit breaks.
Any interruption in W control circuit instantly
closes gas valve and stops gas flow to burners and
pilot. Blower motor continues to run until time-
delay sequence of heat relay is completed.
When air temperature at limit switch drops to the
low-temperature setting of limit switch, switch
closes and completes W control circuit. Electric-
spark ignition system cycles and unit returns to
normal heating operation.
BLOWER SAFETY SWITCH — Blower safety
switeh is a temperature-actuated switch connected
in parallel with contacts of heat relay. Function of
switch is to activate blower should gas valve fail to
close when thermostat is satisfied. Safety switch is
mounted on blower divider panel. When tempera­
ture at safety switch reaches approximately 175 F,
switch closes to start blower. Switch opens when
temperature at switch drops to approximately 116 F.
Cooling Section Start-Up and Adjustments
CHECKING COOLING CONTROL OPERA­
TION — Start and check unit for proper cooling
control operation as follows:
1. Place room thermostat selector switch in OEF
position. Observe that blower motor starts when
fan switeh is placed in ON position and shuts off
when fan switch is placed in AUTO, position.
2. Place selector switch in COOL position and fan
switch in AUTO, position. Set cooling control
below room temperature. Observe that compres­
sor, condenser fan and evaporator blower motors
start. Observe that cooling cycle shuts down
when control setting is satisfied.
3. When using an automatic changeover room
thermostat, place both selector and fan switches
in AUTO, positions. Observe that unit operates
in heating mode when temperature control is set
to call for heating (above room temperature)
and operates in cooling mode when temperature
control is set to call for cooling (below room
temperature).
15