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Section 4 Service Procedures
To reduce the risk of electric shock, fire, explosion, serious injury or death:
• Disconnect electric power to the dryer(s) before servicing.
• Close gas shut-off valve to gas dryer(s) before servicing.
• Never start the dryer(s) with any guards/panels removed.
• Whenever ground wires are removed during servicing, these ground wires must be
reconnected to ensure that the dryer is properly grounded.
W001R1
WARNING
© Copyright, Alliance Laundry Systems LLC – DO NOT COPY or TRANSMIT
23. BURNER SYSTEM OPERATION
Refer to Figure 20
a. Components
(1) This burner has four basic components:
(a.) A silicon carbide (glow bar) igniter
(b.) Burner tube
(c.) Flame sensor
(d.) Two-stage gas valve consisting of a
split-coil valve and a secondary coil
valve.
(2) The split-coil valve is opened when the
dryer thermostat calls for heat, while the
secondary valve does not open until the
igniter has attained ignition temperature.
b. Pre-Ignition Circuits
(a.) When the dryer thermostat calls for
heat, circuits are completed through
the holding coil, flame sensor, booster
coil and igniter.
(b.) Both coils must be energized to open
split-coil valve.
(c.) Once opened, the holding coil can
hold the valve open without assistance
from the booster coil.
(d.) The current shunted around the
secondary coil by the flame sensor,
passes through the igniter causing it to
get hot.
c. Burn Circuit
(1) In approximately 30 seconds, the igniter
attains ignition temperature and the flame
sensor (located on burner housing beside
the igniter) contacts open.
(2) A circuit is then completed through the
secondary coil, opening the valve and
allowing gas to flow.
(3) Ignition is made and the heat from the
burner flame causes the flame sensor
contacts to remain open.
24. IGNITION SYSTEM FEATURES
Refer to Figure 20
a. Momentary Power Interruption
(1) Upon resumption of power, flame sensor
contacts will still be open, permitting
secondary valve to open.
(2) However, with the secondary coil in the
circuit, the booster coil cannot draw
enough current to open the split-coil valve.
(3) When flame sensor contacts do reclose, the
secondary valve will close, and the burner
system will be in the normal pre-ignition
circuit.
b. Flame Failure
(1) In case of flame failure, the flame sensor
contacts will reclose in about 45 seconds.
(2) This will close the secondary valve and the
burner system will be in the normal pre-
ignition circuit.
c. Ignition Failure
(1) If flame is not established as flame sensor
contacts open, secondary valve will remain
open until flame sensor contacts reclose.
(2) Flame sensor will continue to recycle the
igniter and secondary valve (about once
per minute) until ignition is made or dryer
is turned off.
