Troubleshooting Guide
16
READ THIS ENTIRE SECTION BEFORE
BEGINNING TO TROUBLESHOOT PROBLEMS.
The following troubleshooting flow charts provide
procedures for isolating heater problems. The charts are
intended for use by a QUALIFIED GAS HEATER SERVICE
PERSON. DO N
NOT S
SERVICE TTHE H
HEATER U
UNLESS YYOU H
HAVE
BEEN PPROPERLY TTRAINED.
TEST EQUIPMENT REQUIRED
The following pieces of test equipment will be required to
troubleshoot this system with minimal time and effort.
• Digital M
Multimeter - For measuring DC voltage.
• High PPressure G
Gauge - For checking inlet pressures to the
heaters.
INITIAL PREPARATION
1. Visually inspect equipment for apparent damage.
2. Check all wires and gas hoses for abrasion and wear.
Replace any that are suspect.
Heater PProblems
Page
1. Igniter does not spark . . . . . . . . . . . . . . . . . . . . . . . . . . .17
2. Igniter sparks, but heater will not light . . . . . . . . . . . . . .18
3. Heater lights, but will not stay lit . . . . . . . . . . . . . . . . . . .18
4. Burner flame extends beyond case assembly . . . . . . . .18
5. Burner does not shut off after building temperature is
achieved. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .18
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.
OPERATION SEQUENCE:
-- A call for heat occurs from building thermostat.
-- 24 Volts D.C. is sent from building’s temperature control
to heater’s voltage regulator.
-- Voltage regulator reduces incoming D.C. Voltage to
12 Volts D.C. and sends it to On/Off Switch.
-- Switch sends power to ignition control when positioned
to On.
-- Ignition control module begins ignition trial sequence
-- Ignition control sends high voltage to igniter
electrode
-- Igniter sparks
-- Gas control solenoid opens
-- Ignition occurs
-- Igniter continues to spark until flame proving
occurs
-- Ignition spark is shut off
-- Gas control solenoid stays open
-- Building warms to desired temperature
-- Building thermostat is satisfied
-- Heater shuts down
-- Process is repeated on a call for heat
IGNITION FAILURE SEQUENCE:
-- Ignition control will make one ignition trial
-- Trial lasts 6 seconds
-- If ignition control does not establish flame sense within
ignition trial:
-- Ignition spark shuts off
-- Gas valve closes
-- Ignition control system lockout occurs
-- To manually reset the ignition control:
-- Disconnect the heater from its electrical supply,
wait several seconds and then reconnect it.
OR
-- Turn heater’s On/Off switch to Off, wait several
seconds and then turn back to On.
WARNING
Electrical S
Shock aand B
Burn H
Hazard
■
Troubleshooting this system may require operating the
heater with the burner on. Use extreme caution when
working on the heater.
■
Failure to follow this warning may result in property
damage, personal injury or death.
Summary of Contents for PALS
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