L.B. White 170 Premier - Manual (Page 21)

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 and DC voltage and
resistance.
• Low Pressure Gauge - for checking inlet and outlet
pressures at the gas control valve against dataplate
rating.
■
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 is
important as it relates to problem solving.
Four green lights are located next to the selector switch.
Each light will be acitvated in sequence as that circuit within
the heater is verified by the ignition control. If the circuit is
not verified, that respective light will not be activated. The
most common heating mode problems are identified by a
green light being OFF if a specific fault occurs. However,
two other problems may also occur. See the following.
Identify the specif ic problem and then refer to the
appropriate troubleshooting flow chart.
Heating Mode Problems Page
Power status light not on . . . . . . . . . . . . . . . . . . . . . . . . . . 22
Transformer status light not on . . . . . . . . . . . . . . . . . . . . . 22
Air proving status light not on . . . . . . . . . . . . . . . . . . . . . . 23
Gas control status light not on . . . . . . . . . . . . . . . . . . . . . 24
All lights are on, but burner does not light . . . . . . . . . . . . 25
Heater lights but does not stay lit . . . . . . . . . . . . . . . . . . . 26
Ventilation Mode Problem Page
Motor 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:
- The thermostat calls for heat.
--
❂
Light acitvated indicating heater is receiving its
main power supply.
- Line voltage is sent to selector switch.
- Selector switch sends line voltage to the transformer and
to ignition control.
- Transformer reduces line voltage to 24 volts which is sent
to ignition control.
--
❂
Light is activated indicating that ignition control is
receiving 24 volts from transformer.
- Ignition control module performs self safety check.
- Fan motor starts.
- Ignition control module sends 24 volts to air proving
switch.
-- Internal components are tested.
-- Air proving circuit is checked and proven.
--
❂
Light is activated indicating that the air proving
circuit is operating properly.
- Ignition control module begins ignition trial sequence.
- 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.
--
❂
Light is activated indicating that gas control valve
is receiving 24 volts.
-- 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:
- There are three ignition trials. Each trial takes 10
seconds.
- If burner flame is not maintained at the end of the third
trial, the module goes into safety lockout
-- 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.
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 property
damage, personal injury or death.
21
Troubleshooting Information