Bradford White EF120T4003NA3 Service Manual page 44

Vent Safety Switch Testing and Replacement
Error code 67 will display, indicating an open circuit for the vent safety switch. Determine if temperature has reached 190°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 grey wires
(see image below).
Replace vent safety
switch (see Vent
Safety Switch
Replacement
Procedure, pg 41).
Call
N
Technical
Support.
44
Service Procedure XI:
Is there continuity through
grey lead wires of heater
side harness? (see image
below).
N
Depress reset button
on high limit switch. Is
N
there continuity across
high limit switch? (see
image below).
Y
Does the water heater
function?
Y
Reset heater, observe heating
cycle. Does switch open?
Y
Does switch open prior
to 190°F?
Y
Replace vent safety switch (see
Vent Safety Switch Replacement
Procedure, pg 41).
Make sure exhaust collector compartment or exhaust
flue gases are not overheating (190°F) before
resetting vent safety switch. If there is evidence of
overheating, call Technical Support.
Note: Vent safety switch is labeled as
"Exhaust Limit Switch" in wiring diagram.
Y
System O.K.
N
N
Is the temperature over 190°F?
Y
N
DO NOT operate heater. System over heating,
immediately contact Technical Support.
44
WARNING
Vent Safety Switch Location