Bradford White EF Series Service Manual page 14

Thermostat circuit.
(continued from page 12)
Refer to ignition module
illustration, Is there 120VAC
between P1(1) and P1(3)?
Y
Refer to ignition module
illustration, Is there
22 - 27VAC between
P2(1) and P2(2)?
Y
Refer to ignition module
illustration, Is there 24VAC
between P3(9) and P2(1).
N
Replace ignition module.
(see pg 34)
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SERVICE PROCEDURE EF-I
Thermostat Circuit Testing and Replacement
120 volt potential exposure. Use caution
making voltage checks to avoid personal injury.
Check AC source to
determine why there is no
power.
Replace
ignition module.
(see pg 34)
Y
Refer to ignition module
N
illustration, Is there 120VAC
between P7(3) and P7(1)?
N Replace transformer.
(see pg 35)
Check continuity through
ECO, red wires of
thermostat sensor.
Y
Check at temperature
less than 160°F
Is there continuity?
(see photo 6)
N
Check wire harness
continuity. Replace
thermostat sensor or wire
harness as necessary.
(see pg 17)
Replace thermostat
circuit board.
(see pg 15)
WARNING
N
Y
IGNITION MODULE
6
Page 14