before the pressure test. If the test pressure is equal to or less than
0.5 psig (14-in. wc), turn off electric shutoff switch located on the
gas valve before the test. It is recommended that the ground joint
union be loosened before pressure testing.
After all connections have been made, purge the lines and check
for gas leakage with regulated gas supply pressure.
X.
ELECTRICAL CONNECTIONS
This section covers the electrical connections necessary to install
the 376C503 furnace.
A.
115–V Wiring
Refer to the unit rating plate or Table 6 for equipment electrical
requirements. The control system requires an earth ground for
proper operation.
CAUTION:
Do not connect aluminum wire between
disconnect switch and furnace. Use only copper wire.
Make all electrical connections in accordance with the current
edition of the National Electrical Code (NEC) ANSI/NFPA
70-1999 and any local codes or ordinances that might apply. For
Canadian installations, all electrical connections must be made in
accordance with Canadian Electrical Code CSA C22.1, or authori-
ties having jurisdiction.
NOTE:
Proper polarity must be maintained for 115-v wiring. If
polarity is incorrect, control board status code indicator light will
flash rapidly and the furnace will not operate.
WARNING:
The cabinet MUST have an uninterrupted
or unbroken ground according to NEC, ANSI/NFPA
70-1999 and Canadian Electrical 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.
B.
24–V Wiring
Make field 24-v connections at the 24-v terminal strip. (See Fig.
14.) Connect terminal Y as shown in Fig. 15 or proper cooling
operation in cooling mode. Use only AWG No. 18, color-coded,
copper thermostat wire.
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.
C.
Accessories
1. Electronic Air Cleaner (EAC)
Two quick-connect terminals marked EAC-1 and EAC-2
are provided for EAC connection. (See Fig. 14.) These
terminals are energized with 115-v, (1.5-amp maximum)
during blower motor operation.
2. Humidifier (HUM)
A quick-connect terminal (HUM) and screw terminal (C
OM
)
are provided for 24-v humidifier connection. (See Fig. 16.)
HUM terminal is energized with 24-v (0.5-amp maximum)
after inducer pressure switch closes.
WARNING:
DO NOT connect furnace control HUM
terminal to HUM (humidifier) terminal on Thermidis-
tat™, Zone Controller or similar device. See Thermidis-
tat, Zone Controller, thermostat, or controller manufac-
turer’s instructions for proper connection. A failure to
follow this warning could result in fire.
NOTE:
A field-supplied, 115-v controlled relay connected to
EAC terminals may be added if humidifier operation is desired
during blower operation.
XI.
VENTING
Refer to the national or local installation code such as NFGC in the
United States, or the NSCNGPIC in Canada for proper vent sizing
and installation requirements. Use the enclosed Installation In-
structions (Single-Stage Vent Tables for Category I Fan-Assisted
Furnaces) for a quick, easy reference.
After fully assembling the vent connector to the furnace flue collar,
securely fasten the vent connector to the collar with two field-
supplied, corrosion-resistant, sheet metal screws located 180° apart
and midway up the collar.
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.
START-UP
PROCEDURES,
ADJUSTEMENT,
AND
SAFETY CHECK
I.
GENERAL
NOTE:
Proper polarity must be maintained for 115-v wiring. If
polarity is incorrect, control status 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 furnace control. 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).
TABLE 6—ELECTRICAL DATA
UNIT
SIZE
VOLTS—
HERTZ—
PHASE
OPERATING
VOLTAGE RANGE
MAXIMUM
UNIT
AMPS
MIN
WIRE
GAGE
MAXIMUM
WIRE LENGTH (FT)‡
MAXIMUM
FUSE OR CKT BKR
AMPS†
Maximum*
Minimum*
024050
115–60–1
127
104
6.6
14
42
15
036050
115–60–1
127
104
8.1
14
34
15
024070
115–60–1
127
104
6.7
14
42
15
036070
115–60–1
127
104
8.4
14
33
15
036096
115–60–1
127
104
9.2
14
30
15
048096
115–60–1
127
104
10.2
14
28
15
048115
115–60–1
127
104
10.1
14
28
15
060115
115–60–1
127
104
13.3
12
33
20
066115
115–60–1
127
104
15.2
12
29
20
060135
115–60–1
127
104
14.3
12
31
20
* Permissible limits of voltage range at which unit will operate satisfactorily.
† Time-delay type is recommended.
‡ Length shown is a measured 1 way along wire path between unit and service panel for maximum 2 percent voltage drop.
—11—
