Carrier 48KHA - Manual (Page 12)

2. Open air shutter very slowly until yellow tip just
disappears, then secure air shutter in place with
locking screw.
3. Repeat steps 1 and 2 for each burner.
After air shutter adjustments have been com­
pleted, observe that flames on each burner are light
blue and soft in appearance, and that flames are
same height along entire length of each burner. See
Fig. 9.
CARRYOVER
shutter
BURNER
(NAT)
FLAME
RADIATOR
SCREEN
LOW NOx
CARRYOVER
AIR
SHUTTER
MANIFOLD
STANDARD
Fig. 9 — Burner Flames
BLOWER HEAT-RELAY OPERATION — Heat­
ing relay (see Fig. 6 and unit wiring diagram) is
located in the control box and adjusts to permit
either longer or shorter OFF cycles. The ON cycle
automatically adjusts as OFF cycle changes. Adjust­
ing lever on relay is factory-set at center position to
provide optimum performance for most installa­
tions. On unusual installations, or where line voltage
is considerably above or below rated voltage, an
increase or decrease may be required for length of
time blower remains on. To increase blower opera­
tion time, move adjusting lever toward right-hand
position. To decrease blower operation time, move
lever toward left-hand position.
AIRFLOW AND TEMPERATURE RISE — The
heating section of each size of unit is designed and
approved for heating operation within temperature
rise range stamped on unit rating plate.
Table 5 shows approved temperature rise range
for each unit and air delivery (cfm) at various tem­
perature rises. Heating operation airflow must pro­
duce a temperature rise that falls within the
approved range. Refer to Cooling Section Start-Up
and Adjustments — Indoor Airflow and Airflow
Adjustments to adjust heating airflow when
required.
HEATING SEQUENCE OF OPERATION —
See Fig. 10.
Models 48KHA,KLA have an intermittent
electric-spark ignition system without a standing
flame. When manual shutoff is opened, gas flows to
gas valve. On a call for heating by the thermostat,
unit terminal R makes to unit terminal W. Pilot
valve solenoid of gas valve and spark generator are
energized. Gas flows to pilot and the pilot is ignited
within 4 seconds. The flame sensor proves the
presence of pilot flame within 0.8 seconds after pilot
ignition. The internal switching of gas valve de­
energizes spark generator, energizes main valve
solenoid and energizes heating delay relay. Gas
flows to main burners and is ignited by pilot flame.
Contacts of heating relay close between 60 and 90
seconds after burners are ignited, and blower motor
starts. Heating cycle is now in normal operation.
Unit will continue operating in heating cycle until
Table 5 — Air Delivery (cfm) at Indicated Temperature
Rise and Rated Keating Input
MODEL 48-
HEATING
INPUT
(Btuh)
TEMPERATURE RISE (F)
35 37 39 41 43 45 47 49 51 53 55 57 59 61 63 65 67 69 71 73 75
KLA118 40,(Ю0 794 751 712 678 646 617 591 567 545 524 505 487 471 455 441 427 - - - - -
KLA124 40,000 794 751 712 678 646 617 591 567 545 - - - - - - - - - - - -
KHA024 75,000 - -
_ "] 1212 1158 1109 1063 1022 983 947 914 883 854 827 809 778 - - -
KLA130 40,000 617 591 567 545 524 505 487 471 455 - - - - - - -
KHA030 75,000 - - 1271 1212 1158 1109 1063 1022 983 947 914 883 854
KLA036/136 60,000 1190 1126 1068 1016 969 926 887 850 817 786 758 731 706 683 - - - - - - -
KHA036/136 100,000 1984 1877 1781 1694 1615 1543 1478 1417 1362 1310 1263 1218 1177 1138 1102 1068 1036 100$ 978 951 926
KHA036BF/CF 125,000 щщ
1930 1846 1771 1701 1638 1579 1523 1472 1423 1378 1336 1296 1258 1223 1189 1158
KLA042/142 60,000 926 887 850 817 786 758 731 706 683 661 641 622 604 587 571 556
KHA042 125,000 1930 1846 1771 1702 1638 1579 1523 1482 1423 1378 1326 1296 1258 1223 1189 -
KLA048/148 80,000 1235 1182 1134 1089 1048 1010 975 942 911
KHA048 125,000
WM ш
1930 1846 1771 1702 1638 1579 1523 1472 1423 1378 1336 1296 - - - -
KLA160 100,000 1543 1478 1417 1362 1310 1263 1218 1177 1138 1102 - - - - - -
KHA060 150,000 Ä?:
4Шщ
2325 2226 2135 2051 1974 1902 1835 1773 1715 1660 1609 1561 1516 1493 1483 1395
L
NOTE: Shaded areas of the table fall below the approved temperature rise range of the unit Dashed areas
of the table faII beyond the air delivery capability of the unit within the operating voltage range for all voltage
options for each size unit
12