READ THIS ENTIRE SECTION BEFORE BEGINNING
TO TROUBLESHOOT PROBLEMS.
The following troubleshooting guide provides systematic
procedures for isolating equipment problems. This guide is
intended for use by a QUALIFIED GAS HEATER SERVICE
PERSON. DO NOT ATTEMPT TO SERVICE THESE HEATERS
UNLESS YOU HAVE BEEN PROPERLY TRAINED.
TEST EQUIPMENT REQUIRED
The following pieces of test equipment will be required to
troubleshoot this system with minimal time and effort.
• Digital Multimeter - for measuring AC voltage and
resistance.
• Low Pressure Gauge - for checking inlet and outlet
pressures at the gas control valve against dataplate
rating.
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Visually inspect equipment for apparent damage.
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Check all wiring for loose connections and worn
insulation.
Refer to the system operation sequence in this section to
gain an understanding as to how the equipment operates
during a call for heat. Understanding the sequence of
operation of the ignition module and related components is
esential as it will relate directly to problem solving provided
by the flow charts.
The ignition control module is self-diagnostic. The red light,
located within the selector switch, will flash a specific light
pattern depending upon the problem which is diagnosed. To
effectively use the flow charts, you must first identify what
the problem is by the light pattern of the L.E.D. (light
emitting diode) diagnostic light. If the light is flashing, the
flash pattern will be followed by a pause and then a repeat
of the flash pattern until the problem is corrected. Refer to
the tables below to identify what page to refer to when
troubleshooting any problems.
The L.E.D. light will only be on when the selector switch is
positioned to HEAT and the thermostat is set above room
temperature. The light will not be on when the selector
switch is positioned to VENT.
Heating Mode Problems
Page
L.E.D. is steady on. No flash pattern. . . . . . . . . . . . . . . . . . . 23
L.E.D. light is not on. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
Heating Mode Problems (Cont.)
Page
L.E.D. diagnostic light is flashing:
A. One Time . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
B. Two Times . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
C. Three Times . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
D. Four Times . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
E. Five Times . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
Ventilation Mode Problems
Page
A. Motor Does Not Run. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27
B. Motor “Hums,” Does Not Run . . . . . . . . . . . . . . . . . . . . . . 27
C. Motor Runs with Low Air Output. . . . . . . . . . . . . . . . . . . . . 27
Components should be replaced only after each step has been
completed and replacement is suggested in the flow chart.
Refer to the Ser vicing sections as necessar y to obtain
information on disassembly and replacement procedures of the
component once the problem is identified by the flow chart.
DIRECT IGNITION OPERATION SEQUENCE:
-- Selector switch is set to heat.
-- Line voltage is sent to ignition control and to transformer.
-- Red light. on selector switch is illuminated.
-- Transformer reduces line voltage to 24 volts which is sent to
thermostat.
-- The thermostat calls for heat.
-- The thermostat sends 24 volts to ignition control.
-- 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 air proving switch.
-- Ignition control sends line voltage to motor relay
-- Motor relay closes and fan motor starts.
-- Air proving switch closes and 24 volts are 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 cut off.
-- Gas valve stays open.
-- Gas control modulates based upon thermostat.
-- Room warms to desired temperature.
-- Thermostat is satisfied.
-- Gas control closes, burner shuts down.
-- Fan motor continues to run for 1 minute , cooling the
heat chamber.
-- Fan motor stops.
-- Heater shuts off.
-- Process starts again on a call for heat.
IGNITION FAILURE SEQUENCE:
-- Trial for ignition takes approximately 10 seconds.
-- If ignition module does not sense a flame within the ignition
trial, the module goes into safety lockout (3 flash pattern.)
-- Gas valve closes.
-- Ignition spark shuts off.
-- Fan motor stops.
-- To retry for ignition, the systems must be reset:
-- Turn the thermostat down and then up to call for heat or
unplug heater and plug it back in or
-- Position selector switch to off and then back to on.
22
Troubleshooting Information
WARNING
■
This heater can start at any time.
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Troubleshooting this system may require operating the
unit with line voltage present and gas on. Use extreme
caution when working on the heater.
■
Failure to follow this warning may result in property
damage, personal injury or death.