pressure test. If test pressure is equal to or less than 0.5 psig (14-in.
wc), turn OFF electric shutoff switch on gas valve before test. It is
recommended that ground joint union be loosened before pressure
testing. After all connections have been made, purge lines and
check for leakage with regulated gas supply pressure.
Step 6—Electrical Connections
115-V WIRING
Refer to the unit rating plate or Table 5 for equipment electrical
requirements. The control system requires an earth ground for
proper operation.
Do not connect aluminum wire between disconnect switch
and furnace. Use only copper wire.
Make all electrical connections in accordance with the National
Electrical Code (NEC) ANSI/NFPA 70-1999 and local codes or
ordinances that apply. For Canadian installations, all electrical
connections must be made in accordance with CSA C22.1 Cana-
dian Electrical Code, or authorities having jurisdiction.
The cabinet MUST have an uninterrupted or unbroken ground
according to NEC ANSI/NFPA 70-1999 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.
The junction box can be moved to left-hand side of furnace when
a left-hand side power supply is desired. Remove 2 screws holding
the junction box. Mount junction box on left-hand side of furnace.
Holes have been provided in casing. When moved, tuck wiring
harness behind clip provided to keep extra wire lengths out of the
way.
NOTE: Proper polarity must be maintained for 115-v wiring. If
polarity is incorrect, the furnace control status LED will flash
rapidly and prevent heating operation.
24-V WIRING
Refer to ESD Precautions Procedure before proceeding with 24-v
connections.
Make field 24-v connections at 24-v terminal block. (See Fig. 12.)
Connect terminal Y/Y2 as shown in Fig. 13 or 14 for proper
cooling operation. Use only AWG No. 18 or larger, color-coded
copper thermostat wire.
The 24-v circuit contains an automotive-type, 3-amp fuse located
on main control. Any 24-v electrical shorts during installation,
service, or maintenance could cause this fuse to blow. If fuse
replacement is required, use ONLY a 3-amp fuse. The control will
flash code 24 when fuse needs replacement.
ACCESSORIES
1. Electronic air cleaner (EAC)
A terminal block (EAC-1 [hot] and EAC-2 [neutral]) is
provided for EAC connection. (See Fig. 12.) The terminals are
energized with 115v, 1.0-amp maximum during blower motor
operation.
Fig. 11—Typical Gas Pipe Arrangement
A89417
GAS
SUPPLY
MANUAL
SHUTOFF
VALVE
(REQUIRED)
SEDIMENT
TRAP
UNION
Table 4—Maximum Capacity of Gas Pipe*
NOMINAL
IRON PIPE
SIZE (IN.)
INTERNAL
DIAMETER
(IN.)
LENGTH OF PIPE (FT)
10 20 30 40 50
1/2 0.622 175 120 97 82 73
3/4 0.824 360 250 200 170 151
1 1.049 680 465 375 320 285
1-1/4 1.380 1400 950 770 660 580
1-1/2 1.610 2100 1460 1180 990 900
* Cubic ft of gas per hr for gas pressures of 0.5 psig (14-in. wc) or less, and a
supply line pressure drop of 0.5-in. wc (based on a 0.60 specific gravity gas).
Ref: Table 10-2, NFGC.
Fig. 12—Furnace Control
A95231
123
456
78 9
PR2
L2
COM
PR1
L1
EAC-2
EAC-1
HI-COOL
HI-GAS
-HEAT
LO-GAS
-HEAT
PARK
3
FU1
SEC-1
SEC-2
1
123
456
7
8
9
10 11 12
MASTER SLAVE
TWIN
TEST
LED
GRY/Y2W/W1
COM
24 V
W2
1
ON
OFF
FURNACE AND
BLOWER OFF DELAY
SETUP SWITCHES
24-VOLT
THERMOSTAT
TERMINALS
EAC - ELECTRONIC
AIR CLEANER
(115-VAC 1 AMP MAX)
3-AMP
FUSE
LED -
DIAGNOSTIC
LIGHT
TWIN / TEST
TERMINAL
HUM -
HUMIDIFIER
(24-VAC 0.5
AMP MAX)
HUM
10
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