5532522-UIM-B-0619
18
Johnson Controls Ducted Systems
NOTES:
1. Airflow expressed in standard cubic feet per minute (SCFM).
2.
Motor voltage at 115 V.
SECTION VIII: SAFETY CONTROLS
CONTROL CIRCUIT FUSE
A 3-amp fuse is provided on the control circuit board to protect the 24-
volt transformer from overload caused by control circuit wiring errors.
This is an ATO 3, automotive type fuse and is located on the control
board.
BLOWER DOOR SAFETY SWITCH
This unit is equipped with an electrical interlock switch mounted in the
burner compartment. This switch interrupts all power at the unit when
the panel covering the blower compartment is removed.
Electrical supply to this unit is dependent upon the panel that covers the
blower compartment being in place and properly positioned.
AUXILIARY LIMIT SWITCH
The switch is mounted on the burner assembly. If the temperature in the
burner exceeds its set point, the gas valve is de-energized. The opera-
tion of this control indicates a malfunction in the combustion air blower,
heat exchanger or a blocked vent pipe connection. Corrective action is
required.
PRESSURE SENSOR
This furnace is supplied with a pressure sensor, which monitors the flow
through the combustion air/vent piping system.
LIMIT CONTROLS
There is a high temperature limit control located on the furnace vesti-
bule panel near the gas valve. This is an automatic reset control that
provides over temperature protection due to reduced airflow. This may
be caused by:
1. A dirty filter.
2. If the indoor fan motor should fail.
3. Too many supply or return registers closed or blocked off.
The control module will lockout if the limit trips 5 consecutive times. If
this occurs, control will reset & try ignition again after 1 hour.
Table 11:
Blower Performance CFM - Any Position (without filter)
Models
Speed
Airflow Data
(SCFM)
1, 2
Ext. Static Pressure (in. H2O)
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
060A12
High
1363
1328
1282
1257
1211
1180
1145
1100
Medium High
1161
1128
1083
1045
999
959
916
876
Medium
974
941
898
859
811
762
720
667
Medium Low
796
758
714
664
612
562
516
464
Low
720
685
636
589
529
473
431
375
080C16
High
1780
1730
1690
1650
1604
1574
1534
1501
Medium High
1576
1540
1504
1455
1408
1359
1316
1268
Medium
1443
1401
1357
1312
1258
1216
1163
1114
Medium Low
1259
1211
1164
1114
1065
1011
950
894
Low
1080
1030
978
927
872
816
757
680
100C20
High
2197
2138
2096
2052
2007
1958
1904
1869
Medium High
1767
1736
1696
1659
1611
1560
1516
1468
Medium
1581
1521
1476
1442
1400
1344
1295
1250
Medium Low
1406
1358
1316
1269
1222
1177
1131
1087
Low
1205
1146
1098
1039
993
939
890
820
CAUTION
Main power to the unit must still be interrupted at the main power dis-
connect switch before any service or repair work is to be done to the
unit. Do not rely upon the interlock switch as a main power discon-
nect. Blower and burner must never be operated without the blower
panel in place.
!
