Vent Safety Switch Testing And Replacement - Bradford White EF Series Service Manual

Sequence of operation:
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.
120 volt potential exposure. Use caution
making voltage checks to avoid personal injury.
Locate harness
connection.
(see photo 34)
Call technical
support.
Does heater
function?
Reset button
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Vent Safety Switch Testing and Replacement

WARNING
Is there continuity
Through GREY
Lead wires of heater side
harness?
(see photo 34)
N
Depress reset
button on high
N
limit switch. Is
Y
there continuity
across high limit
Y
switch?
(see photo 35)
Service Procedure EF-XII
Y
Replace vent
N
safety switch
(see pg 39)
Reset heater, observe
heating cycle. Does
switch open?
35
Does switch open prior
to 350°F?
Replace vent
safety switch
(see pg 39)
Control side Heater side
harness harness
System OK
N
Is temp over 350°F?
Y
DO NOT OPERATE
HEATER
N
System over heating,
immediately contact
technical support.
Y
34
N
Y
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