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5715184-BIM-A-0519
SECTION V: ELECTRICAL POWER
ELECTRICAL POWER CONNECTIONS
Field wiring to the unit must be grounded. Electric wires that are field
installed shall conform to the temperature limitation for 63°F (35°C) rise
wire when installed in accordance with instructions. Refer to Table 5 in
these instructions for specific furnace electrical data.
Table 5: Ratings and Physical/Electrical Data - MM9E
Nominal
Input
Output
Airflow
MBH kW MBH kW
CFM m
60
17.6
57
16.7
1200
80
23.4
76
22.3
1200
80
23.4
76
22.3
1600
80
23.4
76
22.3
2000
100 29.3
95
27.8
1600
Annual Fuel Utilization Efficiency (AFUE) numbers are determined in accordance with DOE test procedures.
Wire size and over current protection must comply with the National Electrical Code (NFPA-70-latest edition) and all local codes.
The furnace must be installed so the electrical components are protected from water.
SUPPLY VOLTAGE CONNECTIONS
FIGURE 14: Electrical Wiring
1. Provide a power supply separate from all other circuits. Install over-
current protection and disconnect switch per local/national electrical
codes. The switch must be close to the unit for convenience in ser-
vicing. With the disconnect or fused switch in the OFF position,
check all wiring against the unit wiring label. Refer to the wiring dia-
gram in this instruction.
FIGURE 15: Line Wiring Connections
2. Remove the screws retaining the wiring box cover. Route the power
wiring through the opening in the unit into the junction box with a
conduit connector or other proper connection. In the junction box,
there are two wires: a black wire and a white wire. Connect the
power supply as shown on the unit-wiring label on the inside of the
blower compartment door or the wiring schematic in this section.
The black furnace lead must be connected to the L1 (hot) wire from
the power supply. The white furnace screw must be connected to
neutral. Connect the power supply ground to the green screw
(equipment ground). An alternate wiring method is to use a field
provided 2 in. (5.1 cm) x 4 in. (10.2 cm) box and cover on the out-
side of the furnace. Route the furnace leads into the box using a
protective bushing where the wires pass through the furnace panel.
After making the wiring connections, replace the wiring box cover
and screws. Refer to Figure 14.
12
Air Temp.
Max. Outlet
AFUE
Rise
%
3
°F
°C
/min
34.0
95.0 30–60 17–33 190
34.0
95.0 40–70 22–39 190
45.3
95.0 40–70 19–36 190
56.6
95.0 30–60 17–33 190
45.3
95.0 40–70 22–39 190
!
Use copper conductors only.
Blower
Blower
Air Temp
Size
°F
°C
HP
Amps Inches
88
1/2
6.8
11 x 8
88
1/2
6.8
11 x 8
88
3/4
8.4
11 x 10
88
1
10.9
11 x 11
88
3/4
8.4
11 x 10
3. The furnace's control system requires correct polarity of the power
supply and a proper ground connection. Refer to Figure 14.
IMPORTANT: The power connection leads and wiring box may be
relocated to the opposite side of the furnace. Remove the screws
and cut wire tie holding excess wiring. Reposition on the opposite
side of the furnace and fasten using holes provided.
CONVENTIONAL LOW VOLTAGE CONTROL WIRING
Install the field-supplied thermostat by following the instructions that
come with the thermostat. With the thermostat set in the OFF position
and the main electrical source disconnected, connect the thermostat
wiring from the wiring connections on the thermostat to the terminal
board on the ignition module, as shown in Figure 16. Electronic thermo-
stats may require the common wire to be connected. Apply strain relief
to thermostat wires passing through cabinet. If air conditioning equip-
ment is installed, use thermostat wiring to connect the Y and C termi-
nals on the furnace control board to the proper wires on the condensing
unit (unit outside).
IMPORTANT: Set the heat anticipator in the room thermostat to 0.4
amps. Setting it lower causes short cycles. Setting it higher causes
the room temperature to exceed the set points.
IMPORTANT: Some electronic thermostats do not have adjustable
heat anticipators. They must be set to six cycles per hour. Follow
the thermostat manufacturer's instructions.
The 24-volt, 40 VA transformer is sized for the furnace components
only, and must not be connected to power auxiliary devices such as
humidifiers and air cleaners. The transformer may provide power for an
air conditioning unit or heat pump.
FIGURE 16: Single Stage Heat Thermostat Connections
CAUTION
Fuse or
Total Unit
Circuit Breaker
Amps
Amps
15
10.4
15
10.4
15
12.0
20
14.5
15
12.0
Johnson Controls Ducted Systems
Gas Pipe
Connection,
NPT
1/2 in.
1/2 in.
1/2 in.
1/2 in.
1/2 in.
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