Blower Testing And Replacement - Bradford White M1TW40S Series Service Manual

Blower Testing
Step 1. Position gas control power switch
to "ON" position and adjust control to call for heat.
Step 2. Remove the three screws (Phillips Screw driver)
from control access cover on blower assembly and
remove cover (see photo 7).
Does blower energize
Within 2 minutes?
N
8
Does blower energize after
2 minutes, run for 30
seconds and shut down?
N
Disconnect cord set
shown in photo 9. Is
there 115VAC across
terminals shown in
photo 11
N
Is there 115 VAC N
at wall outlet?
Y
Check power cord
Y
for damage.
N
Replace blower
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20
Disconnect
pressure switch
Y
tubing from blower.
(see photo 8)
Pressure tap
9
Pressure
switch tubing
See pressure
Y
switch testing
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Is there 115VAC
Y
across terminals
shown in photo 12 ?
N
Incorrect supply
voltage polarity
Determine
Replace
power source
cord set
problem and
correct.
Repair or replace
power cord
TTW SERVICE PROCEDURE IV

Blower Testing and Replacement

115 volt potential exposure. Use caution when
making voltage checks to avoid personal injury.
7
Connect Disconnect vent
manometer to system from top of
pressure tap of blower and remove
blower. vent adapter.
(see photo 8) (see photo 10)
With blower running, and exhaust
adapter removed from top of
blower, is there a negative
pressure of -2.15" to -2.30" W.C.?
Determine voltage N
problem and correct.
11
Y
Reconnect cord set
shown in photo 9, is
there 115VAC between
blue wire and green
ground wire
(see photo 13)
N
Does cord set
N
have electrical
continuity?
Y
Replace
gas control
WARNING
Y
N
Is there 115vac across
Y
blue and green wires
(see photo 13)
12
Y
Replace blower
Green ground
wire
Shown with pressure
switch removed.
Remove exhaust
adapter
10
Blower OK
Replace blower
13
Blue wire
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