Commander Ductable Make-Up Air Heater
Owner’s Manual •
Commander Ductable Make-Up Air Heater
23
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 THIS HEATER
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.
■ Visually inspect equipment for apparent
damage.
■ Checking all wiring for loose, broken, and worn
connections.
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.
The ignition control modules is a self diagnostic
board. The red fault LED on the control panel will
turn ON if a heater problem is identified. See the
ignition control module for flash code, depending
upon the problem which is diagnosed.
To effectively use the flow charts, you must first
identify what the problem by the flashing pattern
of the red LED light on the control board module.
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 corrrected. Refer to page 21 of this
manual for the LED indications.
Refer to the table below to identify what page to refer to
when troubleshooting any problems.
Heating Mode Problems
Page
Volt meter does not display voltage .................... 25
High limit LED ON .............................................. 25
Fault LED ON ..................................................... 25
Ignition control module troubleshooting .............. 26
Ventilation Mode Problem
Page
Motor Does Not Run. .......................................... 30
Motor “Hums,” Does Not Run.
............................ 30
Motor Runs with Low Air Output. ........................ 30
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:
• Connect proper voltage to the heater.
o Volt meter is activated indicating voltage to the
heater.
• Selector switch is set to HEAT.
o CM500 - Line voltage is sent to transformers and to
ignition module (120V LINE).
o CM1000 - 240 VAC is sent to main transformer.
- Main transformer reduces voltage to 120VAC
and sends it to the two transformers.
• Transformer reduces line voltage to 24VAC
o Top transformer sends 24VAC to ignition control
module (24V) and to high limit switch, modulator
actuator valve.
o Bottom transformer sends 24VAC to the
Temperature Controller.
• Ignition control module sends line voltage to the
minicontactor to run motor.
o Fan motor starts.
• Normally open air pressure switch closes.
o 24VAC is sent to the ignition control module (APS).
• Ignition control module begins ignition trial sequence.
o High voltage is sent out of spark terminal to the
igniter electrode, igniter sparks.
o 24V voltage is send from MAIN VALVE terminal to
gas solenoid relay.
- Gas solenoids opens.
o Ignition occurs.
• Igniter continues to spark until flame proving occurs.
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.
