Electrical Supply - International comfort products N9MP1 Service Manual

Service Manual
6. The Combustion Blower Assembly is mounted on the
outlet side of the Secondary heat exchanger, This
blower creates a partial vacuum (negative pressure)
within the heat exchangers drawing the flue products
out of the furnace.
7. A pressure switch (Air Proving Switch) is used as a
safety device that prevents the ignition system from
WARNING
!
ELECTRICAL SHOCK HAZARD.
Failure to turn off power could result in death or
personal injury.
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.
SUPPLY CIRCUIT
The furnace cannot be expected to operate correctly unless
it is properly connected (wired) to an adequately sized
single branch circuit. Line voltage wires should conform to
temperature limitation of 63° F (35° C) rise and be sized for
the unit maximum amps stated on the rating plate. Add the
full load amps for potential field − installed accessories that
would receive power from the furnace control. Consult NEC
or local codes for proper wire and circuit sizing.
SUPPLY VOLTAGE
Supply voltage to the furnace should be a nominal 115 volts.
It MUST be between 104 volts and 127 volts. Supply volt-
age to the furnace should be checked WITH THE FUR-
NACE IN OPERATION. Voltage readings outside the speci-
fied range can be expected to cause operating problems.
Their cause MUST be investigated and corrected.
ELECTRICAL GROUND
Proper grounding of the electrical supply to THE FURNACE
IS REQUIRED for safety and operational reasons.
POLARITY
CORRECT POLARITY of the line voltage supply to the fur-
nace is also required for safety and operational reasons.
The furnace control MUST have proper line voltage polarity
to operate properly.
6
SEQUENCE OF OPERATION − HEATING
Refer to the ignition control section for sequence of opera-
tion.

ELECTRICAL SUPPLY

Figure 1
NOTE: Junction Box can be
mounted to either the left or right
side.
NOTE: 115 VAC/60Hz/single−phase
Operating voltage range*: 127 VAC max, 104 VAC min.
* Permissible limits of voltage at which unit will operate satisfactorily
CHECKING GROUNDING AND POLARITY
Grounding may be verified as follows:
1. Turn the power supply "OFF".
2. Using an Ohmmeter check for continuity between the
3. With the Ohmmeter set on the R x 1 scale, the read-
4. A zero Ohm reading indicates that the neutral is
Single Stage Multi Position Furnace
firing the furnace until it senses that a proper draft has
been established through the furnace.
Electrical Connections
115V. 60 Hz
W
BK
G
Connection
Box
Ground
R
Low Voltage
G
Terminal Board
W
Y
G
W
R G
Neutral (white) wire and Ground wire (green) of the
supply circuit.
ing should be zero Ohms.
grounded back to the main panel.
Models may
O N
O F F
have 1 or 2
pressure
switches
25−24−90−2
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