Installation Guide
23
ROLLOUT LIMITS
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.
PRESSURE 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.
FLAME SENSOR
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.
T
ROUBLESHOOTING
DIAGNOSTIC C HART
Refer to the troubleshooting chart in the Appendix 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.
RESETTING F ROM L OCKOUT
Furnace lockout results when a furnace is unable to achieve
ignition after three attempts. 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.
M
AINTENANCE
T
O
AVOID
ELECTRICAL
SHOCK
,
INJURY
OR
DEATH
,
DISCONNECT
ELECTRICAL
POWER
BEFORE
PERFORMING
ANY
MAINTENANCE
. I
F
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
.
WARNING
Burner Flame
T
O
AVOID
PERSONAL
INJURY
OR
DEATH
,
DO
NOT
REMOVE
ANY
INTERNAL
COMPARTMENT
COVERS
OR
ATTEMPT
ANY
ADJUSTMENT
.
E
LECTRICAL
COMPONENTS
ARE
CONTAINED
IN
BOTH
COMPARTMENTS
.
C
ONTACT
A
QUALIFIED
SERVICE
AGENT
AT
ONCE
IF
AN
ABNORMAL
FLAME
APPEARANCE
SHOULD
DEVELOP
.
WARNING
S
AFETY
C
IRCUIT
D
ESCRIPTION
GENERAL
A number of safety circuits are employed to ensure safe and proper
furnace operation. These circuits serve to control any potential
safety hazards and serve as inputs in the monitoring and diagnosis
of abnormal function. These circuits are continuously monitored
during furnace operation by the integrated control module.
INTEGRATED 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.
PRIMARY LIMIT
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 resulting from insufficient air passing over the heat
exchanger.
AUXILIARY LIMIT
The auxiliary limit control is located either on or near the circulator
blower and monitors heat exchanger compartment temperatures.
The control is an automatic reset, temperature sensor. It guards
against overheating resulting from insufficient air passing over
the heat exchanger. The auxiliary limit control is suitable for both
horizontal right and horizontal left installations. Regardless of
airflow direction, it does not need to be relocated.