Bradford-White Corp M4TW60T*F, M2TW50T*F, M4TW50T*F, M2TW65T*F Blower Testing, Pressure tap

TTW SERVICE PROCEDURE IV

Blower Testing and Replacement

	WARNING
Blower Testing	115 volt potential exposure. Use caution when
	making voltage checks to avoid personal injury.
Step 1. Position gas control power switch
to “ON” position and adjust control to call for heat.

7

Step 2. Remove the three screws (Phillips Screw driver) from control access cover on blower assembly and remove cover (see photo 7).

Disconnect

Connect

Disconnect vent

manometer to

system from top of

Does blower energize

Y

pressure switch

pressure tap of

blower and remove

Within 2 minutes?

tubing from blower.

blower.

vent adapter.

(see photo 8)

(see photo 8)

(see photo 10)

N

8

Pressure tap

9

With blower running, and exhaust

adapter removed from top of

blower, is there a negative

pressure of -2.15" to -2.30" W.C.?

Pressure

N

switch tubing

Determine voltage

N

Is there 115vac across

Y

blue and green wires

problem and correct.

(see photo 13)

Does blower energize after

Y

See pressure

2 minutes, run for 30

switch testing

11

12

seconds and shut down?

Page 18

N

Disconnect cord set

shown in photo 9. Is

Y

Is there 115VAC

Y

there 115VAC across

across terminals

terminals shown in

shown in photo 12 ?

Reconnect cord set

photo 11

N

shown in photo 9, is

Y

there 115VAC between

N

Incorrect supply

blue wire and green

Replace blower

ground wire

voltage polarity

(see photo 13)

N

Green ground

Determine

Replace

N

Does cord set

wire

Is there 115 VAC

N

power source

have electrical

cord set

problem and

continuity?

at wall outlet?

Y

correct.

Y

Check power cord

Y

Repair or replace

Replace

for damage.

power cord

gas control

N

Remove exhaust adapter

10

Y

Blower OK

Replace blower

13

Blue wire

Replace blower	Shown with pressure
	switch removed.

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