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6. Electrical Wiring
Electrical shock hazard.
Turn OFF electrical power at fuse box or service
panel before making any electrical connections
and ensure a proper ground connection is made
before connecting line voltage.
Failure to do so can result in death, personal injury
and/or property damage.
!
Power Supply Wiring
The furnace
MUST
be electrically wired and grounded in accor-
dance with local codes, or in the absence of local codes with the
latest edition of The National Electric Code, ANSI NFPA 70 and/or
The Canadian Electric Code CSA C22.1.
Field wiring connections must be made inside the furnace connec-
tion box. A suitable strain relief should be used at the point the
wires exit the furnace casing.
Copper conductors must be used
. Line voltage wires should be
sized for the input amps stated on the rating plate. Furnace should
be connected to its own separate circuit.
Thermostat
The 2--stage furnace control will operate with either a single stage
or a two stage heating thermostat and will provide 2--stage heating
operation. For single stage thermostat installations, the
R
and
W
wires from the thermostat connect to the
R
and
W1
connections on
the furnace control.
Note:
The fourth (4th) DIP switch must be in
the off position, failure to change DIP switch will result in Lo Fire
ONLY operation. (See furnace wiring digram) See “
Furnace Wiring
Diagram
” for switch settings. Failure to set DIP switch will result in
Lo fire operation ONLY with single stage thermostat. During opera-
tion, the furnace will operate on low fire for 12 minutesIf the heat
request exists for more than 12 minutes. If the heat request exists
for more that 12 minutes, the furnace will automatically shift to the
high fire mode for the remaining duration of the heating cycle. For
two stage thermostat installations, the
R, W1
and
W2
wires from
the thermostat connect to the
R, W1
and
W2
connections on the
furnace control. During operation, the furnace will shift from low fire
to high fire as requested by the thermostat. The thermostat heat
anticipators should be adjusted to a .10 setting for both types of
thermostats.
Low voltage connections to furnace must be made on terminal
board to fan control.
Optional Equipment
All wiring from furnace to optional equipment
MUST
conform to lo-
cal codes or, in the absence of local codes with the latest edition of
The National Electric Code, ANSI NFPA 70 and/or The Canadian
Electric Code CSA C22.1. Install wiring in accordance with
manufacturer’s instructions. The wiring
MUST
have a minimum
temperature rating of 105
°
C. codes or, in the absence of local
codes, the applicable national codes. Install wiring in accordance
with manufacturer’s instructions.
Humidifier/Electronic Air Cleaner
The furnace is wired for humidifier and/or electronic air cleaner
connection.
CAUTION
Do NOT exceed 115V/0.8 amp. maximum current load for both
the EAC terminal and the HUM terminal combined.
NOTE:
The humidifier will be powered when the furnace is fired
and the circulating air blower comes on. The electronic air cleaner
will be powered anytime the air circulating blower is energized.
However, the electronic air cleaner is
NOT
energized during con-
tinuous fan operation controlled by the electronic fan control.
Fan Control
The fan control is preset at the factory with a fixed blower
ON
delay
of 30 seconds in the heating mode. The blower
OFF
timing is pre-
set at 140 seconds. If desired, the fan
OFF
delay can be reset to
obtain the longest delay times while still maintaining comfort levels.
See “Furnace Wiring Diagram” .
W2
Figure 31
Electrical Connections
NOTE: Junction Box can be mounted to either the left or right side.
25--23--42a
W2
W2
NOTE: 115 VAC/60Hz/single--phase
Operating voltage range*: 127 max, 104 min.
* Permissible limits of voltage at which unit will operate satisfactorily
Dehumidification -- Variable Speed ONLY (*9MPV)
The fan control is wired for 24 VAC normally open (N/O) dehumidis-
tat connection. Connect dehumidistat to the
R
terminal and the
1
/
4
²
male quick connect Y2 terminal on the fan control (See
Figure 32
and “Furnace Wiring Diagram”). A 20% reduction of cooling airflow
will occur when the Y2 dehumidistat terminal is energized during a
call for cooling from the thermostat.
Control Center Fuse
The 24V circuit contains a 5--amp, automotive--type fuse located
on fan timer board. (See
Figure 32
) Any electrical shorts of 24V
wiring during installation, service, or maintenance may cause fuse
to blow. If fuse replacement is required, use only a fuse of identical
size (5 amp.)
Summary of Contents for 9MPT050F12A
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