Vent Safety Switch Testing And Replacement - Bradford White EF100T150(E)*(N Service Manual

Sequence of operation:
For Hot Surface Ignition models, with the thermostat calling for heat, prior to energizing blower, the ignition module checks the
vent safety switch for normal switch position of normally closed. If the vent safety switch contacts are open, (not in normal
position), the ignition module waits indefinitely for contact to close, The vent safety switch must be manually reset to close the
switch contacts.
For Direct Spark Ignition models, error code 26 will display indicating an open circuit for the vent safety switch. Determine if
temperature has reached 350°F before resetting switch and restoring operation. If evidence of extreme temperature is present,
call technical support.
WARNING
120 volt potential exposure. Use caution
making voltage checks to avoid personal injury.
Locate harness
connection.
(see photo at right)
Call technical
support.
N
Does heater
function?
Y
Reset button
WARNING
Make sure exhaust collector compartment is not
overheating (350°F) before resetting vent safety
switch. If there is evidence the collector compartment
is overheating, CALL TECHNICAL SUPPORT.
Is there continuity
Through GREY
Y
Lead wires of heater side
harness?
(see photo at right)
N
Depress reset
Replace vent
button on high
safety switch
limit switch. Is
Y
N
(see "Vent Safety
there continuity
across high limit
Replacement
switch?
Procedure")
(see photo below)
Control side
Switch
Reset heater, observe
heating cycle. Does
switch open?
Y
Does switch open prior
to 350°F?
Y
Replace vent safety
switch
(see "Vent Safety
Switch Replacement
Procedure")
Heater side
harness harness
System OK
N
N Y
Is temp over 350°F?
DO NOT OPERATE
HEATER
N
System over heating,
immediately contact
technical support.
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