60
Table 18 – Speed Selection
UNIT SIZE
RETURN---AIR SUPPLY
SPEED
EXTERNAL STATIC PRESSURE (in. wc)
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1
036060
SIDE/BOTTOM
5(Gry)
1430
1390
1345
1300
1250
1205
1150
1080
995
845
3(Blu)
1240
1200
1145
1100
1040
975
915
860
790
730
4(Yel)
1090
1030
980
935
850
800
730
665
590
525
1(Red)
900
835
780
705
635
565
490
410
335
200
2(Org)
805
620
440
380
300
---
---
---
---
---
036080
SIDE/BOTTOM
5(Gry)
1400
1360
1325
1285
1240
1205
1160
1125
1075
1000
3(Blu)
1340
1300
1265
1215
1180
1135
1100
1055
1015
965
4(Yel)
1195
1160
1115
1065
1025
985
935
895
850
800
1(Red)
1025
980
935
880
835
795
745
685
635
585
2(Org)
855
800
745
680
635
560
515
460
420
360
048080
SIDE/BOTTOM
5(Gry)
1720
1695
1690
1655
1620
1580
1540
1495
1465
1415
3(Blu)
1565
1535
1530
1490
1450
1420
1375
1335
1295
1255
4(Yel)
1330
1310
1270
1220
1180
1135
1095
1055
1010
970
2(Org)
1210
1180
1135
1085
1035
995
950
910
865
810
1(Red)
1110
1065
1005
960
910
865
820
770
720
670
060100
SIDE/BOTTOM
5(Gry)
2070
2020
1985
1925
1890
1850
1795
1755
1690
1610
3(Blu)
1815
1775
1730
1690
1635
1595
1555
1500
1460
1410
4(Yel)
1580
1535
1480
1440
1380
1380
1340
1285
1235
1185
2(Org)
1380
1325
1275
1220
1220
1165
1105
1060
1000
960
1(Red)
1170
1105
1055
985
935
870
805
765
705
660
060120
SIDE/BOTTOM
5(Gry)
2250
2205
2155
2110
2065
2020
1970
1925
1870
1790
3(Blu)
2130
2085
2030
1980
1925
1880
1830
1775
1730
1675
4(Yel)
1890
1835
1790
1740
1690
1640
1590
1535
1480
1435
1(Red)
1640
1585
1525
1475
1425
1365
1315
1260
1200
1140
2(Org)
1420
1370
1305
1255
1190
1135
1065
1010
940
880
NOTES
:
* Airflow shown is with factory supplied 3/4---in. (19 mm) washable filter.*A filter is required for each return air opening.
*An airflow reduction of up to 7% may occur when using the factory---specified 4---5/16---in. (110 mm) wide, high efficiency media filter.
*For best furnace efficiency when using the 4 5/16---in. (110 mm) wide media filter, adjust blower speed tap to near the mid---point of the rise range.
*For horizontal and downflow applications, use one side or bottom or bottom only as an airflow reference.
(Read following caution before changing taps).
UNIT DAMAGE HAZARD
To avoid operating outside the rise range and avoid
component damage:
1. NEVER connect Speed Tap 1 (Red) wire to “HI HT.”
2. NEVER connect Speed Tap 2 (Orange) wire to “HI HT”
on all models.
CAUTION
!
To change blower motor speed selections for heating mode,
remove blower motor lead from control HI-HT terminal. (See
Fig. 37.) Select desired blower motor speed lead from one of the
other motor leads and relocate it to HI-HT terminal. (See Table
18 for lead color identification.) Reconnect original lead on
SPARE terminal. Follow this same procedure for proper selection
of LO-HT and COOL speed selection.
Set Blower Off Delay
a. Remove Blower Access Door if installed.
b. Turn Dip switch 2 and 3 ON or OFF for desired
blower off delay. See Tables 13 and 14 or Fig. 36 and
37.
ADJUST BLOWER OFF DELAY (HEAT MODE)
If desired, the main blower off time delay period may be
lengthened or shortened when operating in the heating mode to
provide greater comfort. See Table 13 for position of switches
and Fig. 36 or 37. for location of switches on control center.
SET THERMOSTAT HEAT ANTICIPATOR
When using a nonelectronic thermostat, the thermostat
heat-anticipator must be set to match the amp draw of
the electrical components in R-W/W1 circuit. Accurate amp
draw readings can be obtained at thermostat subbase terminals
R and W.
Fig. 61 illustrates an easy method of obtaining actual amp draw.
The amp reading should be taken after blower motor has started
and furnace is operating in low heat. To operate furnace in
low-heat, first move SW-1 to ON position, then connect ammeter
wires as shown in Fig. 61. The thermostat anticipator should
NOT be in the circuit while measuring current. If thermostat has
no subbase, the thermostat must be disconnected from R and
W/W1 wires during current measurement Return SW-1 to final
desired location after completing the reading.
See thermostat manufacturer’s instructions for adjusting heat
anticipator and for varying heating cycle length.
When using an electronic thermostat, set cycle rate for 3 cycles
per hour.
Step 6 -- Check Safety Controls
This section covers the safety controls that must be checked
before the installation is complete. The flame sensor, gas valve,
and pressure switch were all checked in the Start-up procedure
section as part of normal operation.
1. Check Primary Limit Control
This control shuts off gas control system and energizes
air-circulating blower motor if furnace overheats.
Recommended method of checking this limit control is to
gradually block off return air after furnace has been
operating for a period of at least 5 minutes. As soon as
limit control has shut off burners, return-air opening
should be unblocked to permit normal air circulation. By
using this method to check limit control, it can be
established that limit is functioning properly and operates
if there is a restricted return-air supply or motor failure. If
limit control does not function during this test, cause must
be determined and corrected.
353BA
V