L.B. White 170 Tradesman Portable Forced Air - Manual (Page 18)

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.
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 is important as it relates to problem solving.
Heater models labeled Tradesman Ultra have a red light
located at the fan end of the heater. The light will flash a
specific pattern depending upon the problem which is
diagnosed. 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. Use the light to help
diagnose the problem.
Heater models labeled Tradesman do not have the
diagnostic red light.
Troubleshooting Flow Charts are provided to eliminate
problems. To use the flow charts effectively, you must first
identify the problem.
Before beginning::
■
Inspect heater for apparent damage.
■
Check all wiring for loose connections and worn
insulation.
Tradesman Ultra Diagnostic Heaters Page
Red light is steady on. No flash pattern. . . . . . . . . . . . . . 19
Red light light is not on. . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
Red light is flashing:
A. One Time . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
B. Two Times . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
C. Three Times . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
D. Four Times. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
D. Five Times . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
Tradesman Non - Diagnostic Heters Page
Fan Does Not Run, Heater Does Not Light. . . . . . . . . . . . 22
Heater Lights, But Does Not Stay Lit . . . . . . . . . . . . . . . . 22
Fan Runs, Heater Does Not Light . . . . . . . . . . . . . . . . . . . 23
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:
-- Voltage is sent to the thermostat.
-- Thermostat calls for heat.
-- Thermostat sends voltage to ignition control.
-- Red light is illuminated.(Ultra heaters only).
-- Ignition control module performs self safety check.
-- Internal components are tested.
-- Air proving circuit is checked.(Ultra heaters only)
-- Ignition control module begins ignition trial sequence.
-- Ignition control module sends 115 volts to air proving .
switch.(Ultra heaters only)
-- Ignition control sends 115 volts to motor, motor starts.
-- Air proving switch closes and 115 volts are returned to the
ignition control module.(Ultra heaters only)
-- Ignition control module sends high voltage to the igniter
electrode.
-- Igniter sparks.
-- Ignition control module sends 115 volts to the gas control
valve through the auto reset 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.
-- Room warms to desired temperature.
-- Thermostat is satisfied.
-- Heater shuts down.
-- 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.
18
Troubleshooting Information
WARNING
■
This heater can start at any time.
■
Troubleshooting this system may require operating the
unit with voltage present and gas on. Be careful when
working on the heater.
■
Failure to follow this warning may result in property
damage, personal injury or death.