Table of Contents
SERVICING
5. Look under the heat shield as the unit is running.
Flames should be drawn into firing tubes.
A. If only one burners flame is not drawn into the
tube, that tube is restricted.
B. If, without the air circulation blower running, all
flames are not drawn into the tubes either the
collector box, combustion blower, or flue outlet
is obstructed. If the combustion blower or flue
outlet is obstructed, the pressure switch should
have opened preventing the unit from firing, also
inspect the unit pressure switch and wiring.
C. If the burner flame is not drawn into the
tube only when the air circulation blower is
running, then a cracked heat exchanger tube is
present.
S-303 Testing Inducer Motor
HIGH VOLTAGE!
Disconnect ALL power before servicing
or installing this unit. Multiple power
sources may be present. Failure to do so
may cause property damage, personal injury
or death.
1. Disconnect the motor wire leads from its connection
point at integrated ignition control module.
2. Using and ohmmeter, test for continuity between
each of the motor leads.
3. Touch one probe of the ohmmeter to the motor
frame (ground) and the other probe in turn to each
lead.
If the windings do not test continuous or a reading is
obtained to ground, replace the motor.
4. After completing check and/or replacement of
induced draft blower motor.
5. Turn on electrical power and verify proper unit
operation.
S-304 Testing Gas Valve
Direct Spark Ignition (DSI) Systems
TWO STAGE MODELS ONLY: A two-stage combination
redundant operator type gas valve which provides all
manual and automatic control functions required for gas
fired heating equipment is used.
The valve provides control of main burner gas flow,
pressure regulation, and 100 percent safety shut-off.
HIGH VOLTAGE!
Disconnect ALL power before servicing
or installing this unit. Multiple power
sources may be present. Failure to do so
may cause property damage, personal injury
or death.
1. Ensure gas valve and main gas supply are on.
2. Using a voltmeter, check from C and M on gas valve
for 24 volts to gas valve.
3. If 24 volts are present and no gas flows through the
valve, replace valve.
Open to
Atmosphere
Outlet
Pressure Boss
Inlet
Pressure Boss
For use with all 3-5 ton models
PRESSURE ADJUSTMENTS
S-305 Checking Main Burners
The main burners are used to provide complete
combustion of various fuels in a limited space, and transfer
this heat of the burning process to the heat exchanger.
Proper ignition, combustion, and extinction are primarily
due to burner design, orifice sizing, gas pressure, primary
and secondary air, vent and proper seating of burners.
Beckett Burner
High Fire Regulator
Adjust
Regulator
Vent
Low Fire
Regulator Adjust
36G54
69
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