L.B. White Tradesman 400 Dual Fuel, Owner'S Manual And Instructions, Page: 22 / 120

Tradesman Construction Heaters
www.lbwhite.com
Owner’s Manual • Tradesman
22
Troubleshooting Guide
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 HEAT-
ERS UNLESS YOU HAVE BEEN
PROPERLY TRAINED.
TEST EQUIPMENT REQUIRED
The following test equipment will be required to
troubleshoot this system with minimal time and
effort.
• Digital Multimeter - for measuring AC voltage
and resistance.
• Pressure Gauge - for checking inlet and pres-
sures at the gas control valve against dataplate
rating.
Ensure all wires and electrical connections are in
good condition before beginning to troubleshoot.
Refer to the system operation sequence in this
section to gain an understanding as to how the
equipment operates during a call for heat. Under-
standing the sequence of operation is important
as it relates to problem solving.
Heater models labeled Tradesman Ul-
tra have a red light located at the fan
end of the heater.
The light will fl ash a spe-
ci fi c pattern depending upon the problem which is
diagnosed. If the light is fl ashing, the fl ash pattern
will be followed by a pause and then a repeat of
the
fl ash 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
fl ow charts effectively, you must fi rst
identify the problem.
Tradesman Ultra Diagnostic Heaters
Page
Red light is not on .................................................... 24
Red light is
fl ashing:
A. One Time............................................................. 25
B. Two Times ........................................................... 26
C. Three Times ........................................................ 27
D. Four Times .......................................................... 27
D. Five Times........................................................... 27
Tradesman Non Diagnostic Heaters Page
Fan Does Not Run, Heater Does Not Light ............. 28
Fan Runs, Heater Does Not Light ........................... 29
Heater Lights, But Does Not Stay Lit ....................... 30
Tradesman 170 Standard Heaters: Do not
have an air proving switch. Voltage is sent
directly to the gas control valve through
both limit switches.
Components should be replaced only after each step has
been completed and replacement is suggested in the
fl ow
chart. Refer to the Servicing sections as necessary to
obtain information on disassembly and replacement proce-
dures of the component once the problem is identi
fi ed by
the fl ow chart.
DIRECT IGNITION OPERATION SEQUENCE: (HEATERS
WITH AIR PROVING SWITCH)
-- Voltage is sent to the thermostat.
-- Thermostat calls for heat.
-- Thermostat sends voltage to ignition control.
-- Red light is illuminated.( Diagnostic Heaters Only).
-- Ignition control module performs self safety check.
-- Internal components are tested.
-- Ignition control module begins ignition trial sequence.
-- Ignition control module sends 115 volts to air
proving switch.
-- Ignition control sends 115 volts to motor
-- Motor starts.
-- Air proving switch closes and 115 volts are returned to
the ignition control module.
-- 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 limit switches.
-- Gas control valve opens.
-- Ignition occurs.
WARNING
■ This heater can start at any time.
■ Troubleshooting this system may require oper-
ating 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.