Bradford White UPDX2-75T6FRN - Manual (Page 33)

Page 33
UPDX Series
Safety Circuit Voltage
Trace WARNING
115 volt potential exposure. Use caution
making voltage checks to avoid personal injury.
Position gas control switch to the “ON”
position and adjust thermostat dial to call
for heat, Is there 10 to 13 VAC between red
wire leading to blower temperature switch
and green ground wire?
Blower must be running during this
voltage check
(see photo 31).
Red wire leading to
blower temp. switch
Green ground wire
31
Yellow wire
leading from
pressure switch
Y
Is there 10 to 13 VAC between yellow wire
leading from pressure switch and green
ground wire
(see photo 31)?
Do you hear or can you see
the igniter sparking?
Y
Y
Is LED on gas valve flashing the
“heartbeat” code (alternating
bright/dim).
N
Safety circuit
voltage is OK.
No voltage from gas control,
call for technical support.
Y
NOTE: This procedure assumes a cool tank.
Verify 115VAC to gas
control (see page 34).
Is there continuity
through blower
temperature switch
(see page 23)?
Y
Check for loose or
broken wire connection
at switch terminals.
N
N
Determine cause of blower
temperature switch activation
and correct.
Check igniter/sensor
(see page 18).
is igniter/sensor OK?
If burner does not light,
observe LED flash code on
gas valve and refer to
troubleshooting section on
page 12
N
N
30
Step 1. Remove three screws (Phillips
Screw driver) from control
access cover on blower and
remove cover (see photos 29 and
30).
Faulty cord set or
gas control.
Y
Correct igniter/
sensor problem.
Control Access
Cover Screws
29
Gas Control shown in
the “ON” Position
UPDX SERVICE PROCEDURE X
Safety Circuit Voltage Trace
33