Carrier 48KLA - COOLING SECTION START-UP AND ADJUSTMENTS; Cooling Control System Verification

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 j
230V or 460V
PHASE (60 Hz) SPEED
j
o o 0 1
0 2
0 3
0 4
0.5 ]
L °ZJ
0.8 0.0 0.1
E9
EEEfl
mm
EI9
EQj
ESI
0.8
Low
Heat
1440 1435 1425
141$
1400 1385 1365 1305 : 1730 1720
1700 1675
1645 1610 1560 1520 1470
Cool
1435 1430
1420
1410 1395
1380 1355 1290 j
1725
1710 1685 1660
1625 1585
1545 1495 1445
KHA04S
208/
Med
Heat 1755 1740 1725 1700 1665 1625 1580 1530 1470 1 1970 j 1945 1910
1875
1825 1775 1720 1660
1600
230-3 j Cool} |
1745 1730 1710 1680 1645 1600 1550
1500
1440 1950 j
1920 1880 i
1840 1790 1735 1685
1625 1570
j
High
Heat
1950
1920
1880 1840
1795 1750 1700
1645
1590 1 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
Heat;
—
_
_
mm
-
—
—
1610 1600 1580 1560
1530 1495
— —
KLA160
230-1 |
Cool
— — -
9
B
— - —
1595
1585 1575 1550 1515
1475
■ H
- —
High |
Heat
n
n
■
H
mm
— 1 _ _
“ i
2375 2280 2185
2095 2000 1905
— —
Cooli
K9
i
9
— — — — ;
2270
2185
2100 2015 1930 1840
—
■
—
Low
Heat
B
B
—
—
—
_
1880
1875 1860 1825 1770 1700
—
H
■
Cool
—
.-.
-
9
— — — -
1875 1865 1840 1790 1725
1650
—
KHAO60
230-1
Med
Heat|
Cool
_
Bl ■
H H
_ _
1
_
2130
2075
2075
2025
2015
1965
1955
1900 ;
1890
1835
1810
1760
—
E
EH
High
Heat
_
■
_ ' _
B
__ ;
2345
2260 2180 2095
2010 1930
_ — —
Cool;
-
1
H Bl
—
-
B
-
2255 2175
2100 2020 1945 1865 |
—
—
—
*Air delivery values are without air filter Deduct field-supplied air filter pressure drop to NOTE: Do not operate the unit at a cooling airflow that is less than 350 fpm per each
obtain external static pressure available for ducting 12,000 Btuh of rated cooling capacity Indoor coil frosting may occur at airflows below
tHeating airflow values are with a dry coil Cooling airflow values are with a wet coil this point
(These 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
thermostat is satisfied. When this occurs, 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 Fig. 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
switch 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 OFF
position. Observe that blower motor starts when
fan switch 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