The cabinet MUST have an uninterrupted or unbroken ground
according to NEC ANSI/NFPA 70-1996 and Canadian Elec-
trical Code CSA C22.1 or local codes to minimize personal
injury if an electrical fault should occur. This may consist of
electrical wire or conduit approved for electrical ground when
installed in accordance with existing electrical codes. Do not
use gas piping as an electrical ground. Failure to follow this
warning could result in electrical shock, fire, or death.
24-V WIRING — Make field 24-v connections at the 24-v termi-
nal strip. (See Fig. 13.) Connect terminal Y as shown in Fig. 14 for
proper operation in cooling mode. Use AWG No. 18 color-coded
wire only.
The 24-v circuit contains an automotive-type, 3-amp fuse located
on the main control board. Any direct shorts during installation,
service, or maintenance could cause this fuse to blow. If fuse
replacement is required, use ONLY a 3-amp fuse of identical size.
ACCESSORIES
1. Electronic Air Cleaner (EAC)
Two spring clamp terminals (for 12 gage maximum, solid or
stranded wire), marked EAC-1 and EAC-2, are provided for
EAC connection. (See Fig. 13.) These terminals are energized
with 115v (1.5-amp maximum) during blower motor opera-
tion. To connect EAC power leads to furnace control board,
strip approximately 1/8 in. of insulation from wire. Open
terminal by depressing switch arm with a screwdriver or
finger, and insert wire as shown in Fig. 15.
2. Humidifier (HUM)
Screw terminals (HUM and Com) are provided for 24-v
humidifier connection. The terminals are energized with 24v
(0.5-amp maximum) after inducer motor prepurge period.
NOTE:
A field-supplied, 115-v controlled relay connected to
EAC terminals may be added if humidifier operation is desired
during blower operation.
Step 9—Venting
Refer to the National or Local Installation Code such as; National
Fuel Gas Code NFPA No. 54-1996/Z223.1-1996, or the Canadian
Installation Code, CAN B149.1- and .2-M95, for proper vent
sizing and installation requirements. Use the enclosed Venting
Tables for Category I Fan-Assisted Furnaces for a quick, easy
reference. The horizontal portion of the venting system shall
maintain a minimum of 1/4-in. upward slope per linear ft and it
shall be rigidly supported every 5 ft or less with hangers or straps
to ensure that there will be no movement after installation.
Step 10—Start-up, Adjustment, and Safety Check
GENERAL
NOTE:
Proper polarity must be maintained for 115-v wiring. If
polarity is incorrect, control board fault indicator light will flash
rapidly and furnace will not operate.
The furnace must have a 115-v power supply properly connected
and grounded. Proper polarity must be maintained for correct
operation. Thermostat wire connections at R, W, C, and Y must be
made at the 24-v terminal block on the control board. The gas
service pressure must not exceed 0.5 psig (14-in. wc), but must be
no less than 0.16 psig (4.5-in. wc).
Before operating the furnace, check each manual reset switch for
continuity. If necessary, press the button to reset the switch.
The blower compartment door must be in place to complete the
115-v circuit to the furnace.
This furnace is equipped with 2 manual reset limit switches in
the gas control area. The switches will open and shut off
power to the gas valve if a flame rollout or an overheating
condition occurs in the gas control area. DO NOT bypass the
switches. Correct inadequate combustion air supply problem
and reset the switches.
SEQUENCE OF OPERATION
Furnace control must be grounded for proper operation or
control will lockout. Control is grounded through green wire
routed to gas valve and burner bracket screw.
Using the schematic diagram shown in Fig. 16, follow the
sequence of operation through the different modes. Read and
follow the wiring diagram very carefully.
NOTE:
If there is a power interruption and any thermostat call,
the control will initiate a 90-sec blower only on period before
starting another cycle.
1. Heating mode
When the thermostat "calls for heat," R-W circuit closes. The
furnace control performs a self-check, verifies the pressure
switch contacts are open, and starts the inducer motor.
Table 6—Electrical Data
UNIT SIZE
VOLTS—
HERTZ—
PHASE
OPERATING VOLTAGE RANGE
MAXIMUM
UNIT AMPS
MINIMUM
WIRE GAGE
MAXIMUM WIRE
LENGTH FT‡
MAXIMUM
FUSE OR HACR-
TYPE CKT BKR
AMPS†
Maximum*
Minimum*
050-08
115—60—1
127
104
6.6
14
42
15
050-12
115—60—1
127
104
8.1
14
34
15
070-08
115—60—1
127
104
6.7
14
42
15
070-12
115—60—1
127
104
8.4
14
33
15
096-12
115—60—1
127
104
9.2
14
30
15
096-16
115—60—1
127
104
10.2
14
28
15
115-16
115—60—1
127
104
10.1
14
28
15
115-20
115—60—1
127
104
13.3
12
33
20
115-22
115—60—1
127
104
15.2
12
29
20
135-20
115—60—1
127
104
14.3
12
31
20
* Permissible limits of the voltage range at which the unit will operate satisfactorily.
† Time-delay fuse is recommended.
‡ Length shown is as measured 1 way along wire path between unit and service panel for maximum 2 percent voltage drop.
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