Bradford-White Corp U4TW60T*FRN Manual De Usuario

Page 26

Pressure Switch Testing (cont’d)

Pressure Switch Testing

Pressure switch

wire leads

With steps 1,2 & 3

complete, discon-

nect wire leads

from pressure

switch.

Use a multi-meter

set to the ohms

setting. With

blower off, check

across the pres-

sure switch termi-

nals. Are the

switch contacts

open (no electrical

continuity)?

Position the gas

control power

switch to the “ON”

position and adjust

the thermostat to

call for heat. This

will start the

blower. Check with

the multi-meter.

Do the pressure

switch contacts

close with the

blower running?

The switch contacts

are OK. See safety

circuit trace (page

40).

Check the tubing and

pressure tap on switch

for blockage. Is there

a blockage?

Check the tub-

ing and pressure
tap on switch for

blockage. Is

there a block-

age?

Clear blockage

Replace switch
(see page 27).

Is the vent

system

blocked?

Is vent system

length within the

vent table specifi-

cations listed on

pages 9 & 10?

Reconfigure vent

system to be

compliant with

vent tables.

See blower

testing (page

28). Is the

Blower OK?

Correct the

blower prob-

lem.

Y

N

N

N

N

N

N

Y

Y

N

Y

Y

Y

26