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Troubleshooting Instructions
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 NNOT AATTEMPT TTO SSERVICE TTHESE HHEATERS
UNLESS YYOU HHAVE BBEEN PPROPERLY TTRAINED.
TEST EEQUIPMENT RREQUIRED
The following pieces of test equipment will be required to
troubleshoot this system with minimal time and effort.
• Digital MMultimeter
- for measuring voltage and resistance.
• Low PPressure GGauge
- for checking inlet and outlet
pressures at the gas control valve against dataplate
rating.
INITIAL PPREPARATION
■ Visually inspect equipment for apparent damage.
■ 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 heater operates during
a call for heat.
Understanding the sequence of operation of the ignition
module and related components is essential as it relates
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
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 code) 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 following tables to identify what page to refer to when
troubleshooting any problems.
The light will only be on when the selector switch is
positioned to HEAT and the thermostat or controller is
calling for heat. The light will not be on when the selector
switch is positioned to VENT.
Heating MMode PProblems
Page
L.E.D. is constant on. No flash pattern. . . . . . . . . . . . . . . . . 20
L.E.D. light is not on. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
L.E.D. diagnostic light is flashing:
A. One Time. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
B. Two Times. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
C. Three Times . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
D. Four Times . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
Ventilation MMode PProblems Page
A. Motor Does Not Run. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
B. Motor “Hums,” Does Not Run . . . . . . . . . . . . . . . . . . . . . . 24
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 IIGNITION OOPERATION SSEQUENCE:
-- Selector switch is set to heat.
-- Line voltage is sent to ignition control and to transformer.
-- Red L.E.D. 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 120 volts to motor.
-- 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 to first or second stage
heating based upon thermostat setting.
-- Room warms to desired temperature.
-- Temperature control is satisfied.
-- Heater shuts down.
-- Process starts again on a call for heat.
IGNITION FFAILURE SSEQUENCE:
-- 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 system 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.
WARNING
■ This heater can start at any time.
■ 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 personal
injury or death.
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