20
Heating Mode Problems
Page
L.E.D. is not on, but heater is operating properly
during a call for heat . . . . . . . . . . . . . . . . . . . . . . . . . . . .21
L.E.D. is steady on. No flash pattern . . . . . . . . . . . . . . .21
L.E.D. light is not on during a call for heat. Fan
motor does not run, heater does not light . . . . . . . . . . .22
Heater has gone into safety lock-out.
L.E.D. diagnostic light is flashing:
A. Two Times . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .23
B. Three Times . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .24
C. Five Times . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .25
Ventilation Mode Problems
Page
A. Motor Does Not Run . . . . . . . . . . . . . . . . . . . . . . .26
B. Motor “Hums”, Does Not Run . . . . . . . . . . . . . . .26
Components should be replaced only after each step has
been completed and replacement is suggested in the flow
chart. Refer to the “Servicing” sections as necessary to
obtain information on disassembly and replacement
procedures of the component once the problem is identified
by the flow chart.
DIRECT IGNITION OPERATION SEQUENCE:
— Line Voltage is Sent to Selector Switch
— Selector Switch Sends Line Voltage to the Thermostat
— A Call for Heat Occurs from the Thermostat
— Thermostat Sends Line Voltage to the Transformer and
to the Motor Relay Contacts
— Transformer Sends 24 Volts to the Circuit Breaker
— Circuit Breaker Sends 24 Volts to the Ignition Control
Module
— Red L.E.D. on Control Module is
I
lluminated
— Ignition Control Module Performs Self Safety Check
-- Internal Components are Tested
-- Air Proving Circuit is Checked
— Ignition Control Module Begins Ignition Trial Sequence
— Ignition Control Module Sends 24 Volts to the Motor
Relay Coil and to Air Proving Switch
-- Fan Motor Starts
-- Air Proving Switch Closes and 24 Volts is Returned to
the Ignition Control Module
— Ignition Control Module Sends High Voltage to the
Igniter Electrode
-- Igniter Sparks
— Ignition Control Module Sends 24 Volts to the Gas
Control Valve through the High Limit Switches
-- Gas Control Valve Opens
— Ignition Occurs
-- Igniter Continues to Spark until Flame Proving Occurs
-- Ignition Spark is Shut Off
-- Gas Valve Stays Open
— Room Warms to Desired Temperature
-- Thermostat is Satisfied
-- Heater Shuts Down
— Process Starts Again on a Call for Heat