Installation Manual

23
An electrical disconnect must be installed readily
accessible from and located within sight of the furnace.
See Figure 21 (page 23) or the wiring diagram label
inside of the control door. Any other wiring methods
must be acceptable to authority having jurisdiction.
Proper line voltage polarity must be maintained in
order for the control system to operate correctly.
Verify the incoming neutral line is connected to the
white wire and the incoming HOT line is connected
to the black wire. The furnace will not operate unless
the polarity and ground are properly connected as
shown in Figure 21.
Thermostat / Low Voltage Connections
• The furnace is designed to be controlled by a 24 VAC
thermostat. The thermostat’s wiring must comply with
the current provisions of the NEC (NFPA 70) and with
applicable local codes having jurisdiction.
• The thermostat must be installed according to the
instructions supplied by the thermostat manufacturer.
Low voltage connections (24 VAC) from the thermostat
Figure 21. 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.
FURNACE
MODEL
NUMBER
MG2R-
FURNACE
INPUT
(BTUH)
CABINET
WIDTH
(IN.)
NOMINAL
ELECTRICAL
SUPPLY
MAXIMUM
OPERATING
VOLTAGE
MINIMUM
OPERATING
VOLTAGE
MAXIMUM
FURNACE
AMPERES
MAXIMUM
FUSE OR CIRCUIT
BREAKER AMPS*
MINIMUM
CIRCUIT
AMPACITY
1
045 45,000 19 7/8 115-60-1 127 103 10.8 20 13.44
060 60,000 19 7/8 115-60-1 127 103 10.8 20 13.44
072 72,000 19 7/8 115-60-1 127 103 10.8 20 13.44
NOTE: Minimum wire gauge and maximum fuse/circuit breaker amperage are based on MCA
1
and MOP
2
calculations. Wire sizing for this furnace
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 recommended.
Table 5. Wire Length & Voltage Specifications
are wired to the terminal strip on the integrated control
in the furnace. Figure 22 (page 24)contains the
proper connections for heating only (two-wire) and
heating/cooling (four-wire) applications. Recommended
minimum wire gauge for thermostat wiring is shown in
Table 5, (page 23).
• The thermostat should be mounted about 5 feet above
the floor on an inside wall. DO NOT install the thermostat
on an outside wall or any other location where its
operation may be adversely affected by radiant heat from
fireplaces, sunlight, or lighting fixtures, and convective
heat from warm air registers or electrical appliances.
Refer to the thermostat manufacturer’s instruction sheet
for detailed mounting information.
Heat Anticipator
Set the heat anticipator according to the instructions
supplied by the thermostat manufacturer. To determine
the heat anticipator setting:
1. Add the current draw of the system components; or
2. Measure the current flow on the thermostat R-W circuit
after the circulating blower motor has started.