Electrical Control Connections; Safety Controls - Coleman P*HU Installation Instruction

ELECTRICAL CONTROL CONNECTIONS

Install the field-supplied thermostat. The thermostat instruc-
tions for wiring are packed with the thermostat. With the ther-
mostat set in the OFF position and the main electrical source
disconnected, complete the low-voltage wiring from the ther-
mostat to the terminal board on the low-voltage transformer.
Connect Class 2 control wiring, refer to Figure 13.
Apply strain relief to thermostat wires passing through the
cabinet.
FIGURE 13 : TYPICAL HEATING AND COOLING
Set the heat anticipator in the room thermostat
to.45 amps. Setting it lower will cause short
cycles. Setting it higher will cause the room tem-
perature to exceed the set point.
NOTE: Some electronic thermostats do not have adjustable
heat anticipators. They may have other type cycle rate
adjustments. Follow the thermostat manufacturer's instruc-
tions.
The 24-volt, 40 VA transformer is sized for the furnace com-
ponents only, and should not be connected to auxiliary
devices such as humidifiers, air cleaners, etc. The trans-
former may provide power for an air conditioning unit contac-
tor.

SAFETY CONTROLS

Blower Door Safety Switch:This unit is equipped with an
electrical interlock switch mounted in the blower compart-
ment. This switch interrupts all power at the unit when the
panel covering the blower compartment is removed.
CAUTION
Blower and burner must never be operated without
the blower panel in place.
16
Electrical supply to the unit is dependent upon the panel that
covers the blower compartment being in place and properly
positioned.
CAUTION
Main power supply to the unit must still be inter-
rupted at the main power disconnect switch before
any service or repair work is to be done to the unit.
Do not rely upon the interlock switch as a main
power disconnect.
Rollout Switch Controls:These controls are mounted on the
burner assembly. If the temperature in the burner compart-
ment exceeds its set point, the ignition control and the gas
valve are de-energized. This is a manual reset control and
must be reset before operation can continue.
The operation of this control indicates a malfunction in the
combustion air blower or a blocked vent pipe connection.
Pressure Switch:This furnace is supplied with a differential
pressure switch which monitors the flow of combustion prod-
ucts through the furnace and venting system. This switch de-
energizes the ignition control module and the gas valve if any
of the following conditions are present:
1. Blockage of internal flue gas passageways.
2. Blockage of vent piping.
3. Failure of combustion air blower/motor.
Limit Control:The high temperature limit control is located
on the furnace vestibule panel just to the right and below the
gas valve. This is an automatic reset control and provides
over temperature protection due to reduced airflow, such as a
dirty filter.
Auxiliary Limit Controls:These high temperature limit con-
trols are located in the blower compartment, one on each
side on upflow/horizontal unit. Downflow units have a single
limit mounted on the blower assembly. These are manual
reset controls and provide high temperature protection when
the unit is applied in the horizontal position.
Control Circuit Fuse: A 3 amp fuse is provided to protect
the 24 volt transformer from overload caused by control cir-
cuit wiring errors. This is an ATO 3, automotive type fuse and
is located on the ignition control module refer to Figure 14.
035-17405-000 Rev. B (0801)
Unitary Products Group