25
Red LED Flash
Error / Condition
1
System Lockout (Retries Exceeded)
2
Pressure Switch stuck Closed
3
Pressure Switch stuck Open
4
Open Main or Auxillary Temperature Limit Switch
5
Flame Sensed>4.25 Seconds with Gas Valve De-Energized
6
Open Rollout Temperature Limit Switch
8
Igniter Relay Fault
10
Open Fuse
11
Igniter Open
12
Inducer Relay Error/Improper Grounding
7
Low Flame Sense Signal
9
Twinning Fault
OFF
Control Failure / No Power / Internal Fault / IRQ Loss. Gas Heating
Lockout (Gas valve energized when it should be de-energized) Or Gas
Valve De-energized when it should be Energized
Rapid Flash
Reverse Polarity
Continuous On Normal Operation
ERROR CODE
Flash Codes stored in memory (auto-erased after 14 days)
Flash Codes NOT stored in memory
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 cir-
culator blower and monitors heat exchanger compartment
temperatures. The control is an automatic reset, temperature
sensor. It guards against overheating resulting from insuffi
-
cient 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.
Rollout Limits
The rollout limit controls are mounted on the burner/manifold
assembly and monitor the burner flame. They are manual-re
-
set, temperature sensors. This limit guards against burner
flames not being properly drawn into the heat exchanger.
Pressure Switches
The pressure switches are normally-open, negative air pres-
sure-activated switches. They monitor the airflow (combus
-
tion 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.
Burner Flame
The burner flames should be inspected with the burner com
-
partment door installed. Flames should be stable, quiet, soft,
and blue (dust may cause orange tips but they must not be
yellow). Flames should extend directly outward from the
burners without curling, floating, or lifting off. Flames must
not impinge on the sides of the heat exchanger firing tubes.
Burner Flame
WARNING
To avoid personal injury or death, do not remove any internal
compartment covers or attempt adjustment. Electrical
components are contained in both compartments. Contact
a qualified service agent at once in an abnormal flame
appearance should develop.
SAFETY CIRCUIT DESCRIPTION
WARNING
DO NOT BYPASS SAFETY DEVICES
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 monitor-
ing and diagnosis of abnormal function. These circuits are
continuously monitored during furnace operation by the inte-
grated control module.
Integrated Control Module
The integrated control module is an electronic device which
controls all furnace operations. Responding to the thermo-
stat, the module initiates and controls normal furnace op-
eration, 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.
