29
I
NTEGRATED
C
ONTROL
M
ODULE
The integrated control module is an electronic device which
controls all furnace operations. Responding to the thermostat,
the module initiates and controls normal furnace operation, and
monitors and addresses all safety circuits. If a potential safety
concern is detected, the module will take the necessary
precautions and provide diagnostic information through an LED.
P
RIMARY
L
IMIT
The primary limit control is located on the partition panel and
monitors heat exchanger compartment temperatures. It is an
automatic reset, temperature sensor. The limit guards against
the overheating as a resulting of insufficient air passing over the
heat exchanger.
A
UXILIARY
L
IMIT
The auxiliary limit control is located either on or near the circulator
blower and monitors heat exchanger compartment temperatures.
The control is a temperature sensor. It guards against overheating
resulting from insufficient air passing over the heat exchanger.
R
OLLOUT
L
IMITS
The rollout limit controls are mounted on the burner/manifold
assembly and monitor the burner flame. They are manual-reset,
temperature sensors. This limit guards against burner flames
not being properly drawn into the heat exchanger.
P
RESSURE
S
WITCHES
The pressure switches are normally-open, negative air pressure-
activated switches. They monitor the airflow (combustion air and
flue products) through the heat exchanger via pressure taps located
on the induced draft blower. These switches guard against
insufficient airflow (combustion air and flue products) through the
heat exchanger.
F
LAME
S
ENSOR
The flame sensor is a probe mounted to the burner/manifold
assembly which uses the principle of flame rectification to
determine the presence or absence of flame.
XV. TROUBLESHOOTING
E
LECTROSTATIC
D
ISCHARGE
(ESD) P
RECAUTIONS
NOTE:
Discharge body’s static electricity before touching unit. An
electrostatic discharge can adversely affect electrical components.
Use the following precautions during furnace installation and
servicing to protect the integrated control module from damage.
By putting the furnace, the control, and the person at the same
electrostatic potential, these steps will help avoid exposing the
integrated control module to electrostatic discharge. This
procedure is applicable to both installed and uninstalled
(ungrounded) furnaces.
1. Disconnect all power to the furnace. Do not touch the
integrated control module or any wire connected to the
control prior to discharging your body’s electrostatic
charge to ground.
2. Firmly touch a clean, unpainted, metal surface of the
furnace away from the control. Any tools held in a person’s
hand during grounding will be discharged.
3. Service integrated control module or connecting wiring
following the discharge process in step 2. Use caution
not to recharge your body with static electricity; (i.e., do not
move or shuffle your feet, do not touch ungrounded objects,
etc.). If you come in contact with an ungrounded object,
repeat step 2 before touching control or wires.
4. Discharge your body to ground before removing a new
control from its container. Follow steps 1 through 3 if
installing the control on a furnace. Return any old or new
controls to their containers before touching any ungrounded
object.
D
IAGNOSTIC
C
HART
Refer to the troubleshooting chart on the following pages for
assistance in determining the source of unit operational problems.
The red diagnostic LED blinks to assist in troubleshooting the
unit. The number of blinks refer to a specific code.
R
ESETTING
F
ROM
L
OCKOUT
Furnace lockout results when a furnace is unable to achieve
ignition after three attempts, or when it has lost flame five times
during a single call for heat. It is characterized by a non-functioning
furnace and a one flash diagnostic LED code from the red LED. If
the furnace is in “lockout”, it will (or can be) reset in any of the
following ways.
1. Automatic reset. The integrated control module will
automatically reset itself and attempt to resume normal
operations following a one hour lockout period.
2. Manual power interruption. Interrupt 115 volt power to the
furnace for 1 - 20 seconds.
3. Manual thermostat cycle. Lower the thermostat so that
there is no longer a call for heat for 1 -20 seconds then
reset to previous setting.
NOTE:
If the condition which originally caused the lockout still
exists, the control will return to lockout. Refer to the Diagnostic
Chart for aid in determining the cause.
XVI. MAINTENANCE
WARNING
T
O AVOID ELECTRICAL SHOCK, INJURY OR DEATH, DISCONNECT ELECTRICAL
POWER BEFORE PERFORMING ANY MAINTENANCE. IF YOU MUST HANDLE THE
IGNITER, HANDLE WITH CARE.
T
OUCHING THE IGNITER ELEMENT WITH BARE
FINGERS, ROUGH HANDLING, OR VIBRATION COULD DAMAGE THE IGNITER
RESULTING IN PREMATURE FAILURE.
O
NLY A QUALIFIED SERVICER SHOULD
EVER HANDLE THE IGNITER.
A
NNUAL
INSPECTION
The furnace should be inspected by a qualified installer, or service
agency at least once per year. This check should be performed at
the beginning of the heating season. This will ensure that all
furnace components are in proper working order and that the
heating system functions appropriately. Pay particular attention to
the following items. Repair or service as necessary.
