MG2S Installation Manual

33
Furnace
Model
Number
MG2S-
Furnace
Input
(Btuh)
Cabinet
Width
(in.)
Nominal
Electrical
Supply
Maximum
Operating
Voltage
Minimum
Operating
Voltage
Maximum
Furnace
Amperes
Minimum
Wire
Gauge
Maximum
Fuse or Circuit
Breaker Amps*
045A 45,000 19 7/8 115-60-1 127 103 8.8 14 15
060A 60,000 19 7/8 115-60-1 127 103 8.8 14 15
072A 72,000 19 7/8 115-60-1 127 103 8.8 14 15
NOTE: Minimum wire gauge and maximum fuse/circuit breaker amperage are based on MCA
1
and MOP
2
calculations. This furnace is
approved for installation with a 15 or 20 amp fuse/circuit breaker however wiring sizing must adhere to current version of the NEC and/or
applicable local codes depending upon the overcurrent protection.
Thermostat Wire Gauge
Recommended Thermostat Wire Length
2 - wire - Heating 4 or 5 wire - Cooling
24 55 ft. 25 ft.
22 90 ft. 45 ft.
20 140 ft. 70 ft.
18 225 ft. 110 ft.
* Time-delay fuses or circuit breakers are required.
Table 8. Wire Length & Voltage Specifications
Figure 25. Line Voltage Field Wiring
Field Supplied
Panel Connector
Field Supplied
Fused Service
Panel
Black (Hot)
White (Neutral)
Green or Bare
(Ground)
Black
White
Black
White
Field Line Voltage Wiring
Factory Line Voltage Wiring
Ground
Ground
Junction box may be interior or exterior to the furnace,
but must be installed such that it is inaccessible without
tools. These connections can be made in the field supplied
disconnect at the furnace. NOTE: Connections made within
the furnace burner compartment do not require a junction bo
x.
Electircal Diagrams & Data
Figure 27. Two-Stage Furnace Control Board
11
4 1
8
7
10
5 2
9 3
12
6
LINE- N
XMFR-N
LINE
LINE
XMFR
EAC
HUM
LINE- N
14325
R
C
Y/Y2
W2
G
W1
Y1
GREEN
OFF
ON
EXPANSION
PORT
FOR WIRING TO THE
MOTOR CONTROL
BOARD
60
RED
STATUS
90
120
180
YELLOW
AUTO
STAGE
BLOWER
OFF
DELAY
THERMOSTAT CONNECTIONS
NEUTRALS
(FLAME)
FUSE
INPUTS
Figure 26. MG2S Motor Control Board
GREEN
RED
STAT US
NOT USED
NOT USED
CONNECTION TO
FURNACE CONTROL
BOARD
MOTOR WIRE
HARNESS
RCY1
TWIN
DHUM
W1
THERMOSTAT
EXPANSION
PORT
COOL
HEAT
FAN SPEED
1 2 3
4
5 6 7
8
OFF ON
CONNECTION
TERMINAL TO
TWIN FURNACES