Blower Testing And Replacement; Exhaust Pressure Switch Testing And Replacement - Bradford White EF60T125 Service Manual

Sequence of operation:
With the thermostat calling for heat, prior to energizing blower, the ignition module checks the exhaust pressure switch for normal
switch position of normally open. If the exhaust pressure switch contacts are closed (not in normal position), the ignition module
waits 45 seconds for the pressure switch contacts to open. If the pressure switch contacts do not open after 45 seconds, the
ignition module locks out with the PURGE LED flashing indicating a pressure switch fault.
LED Status
Only power LED is on, or
Purge LED flashing.
Does blower
energize?
Y
Switch Testing and
Check PURGE LED status.
On within 5 minutes?
N
Flashing after
5 minutes?
Y
Check blower for proper
operation (see page 27)
Is blower OK?
Y
Refer to
"Check Collector Pressure"
(see next page)
54

Exhaust Pressure Switch Testing and Replacement

Safety Circuit Trace
Is there continuity
Through GREY
N
wire leads of heater side
safety circuit harness?
(see photo below)
Call technical
support.
Depress reset
button on vent
N
safety switch. Is
Does heater
Y
there continuity
function?
across high limit
switch?
Y
(see photo below)
Verify proper
switch operation.
(see "Vent Safety
Replace vent safety
switch.
Replacement")
(see "Vent Safety
Switch Replacement
Procedure")
Y
Pressure switch is OK.
Call for technical
N
support.
Correct blower problem
N
(see "Blower Testing and
Replacement")
For serial numbers prior to "CF"
120 volt potential exposure. Use caution
making voltage checks to avoid personal injury.
Is there continuity
Y
wire leads of heater side
safety circuit harness?
(see photo below)
N
Check PURGE LED status
on ignition module,
Flashing after 45 seconds?
N
Reset button
WARNING
through RED Safety Circuit OK,
N
(see "Blower Testing
& Replacement")
Y
Replace exhaust
pressure switch (see
Y
"Exhaust Pressure
Switch Replacement
Control side Heater side
harness harness
Procedure")
54