Bradford White IGI-180R-10 Service Manual page 34

VI - TROUBLESHOOTING
Troubleshooting Flow Chart
BEFORE CARRYING OUT CHECKS MARKED WITH
A # SIGN, DISCONNECT THE POWER SUPPLY.
Examination
Nature of Fault Point
C. Combustion 1. Check flame rod.
occurs, but flame
fails.
Error code "12"
displayed on
digital monitor. 2. Check ground
wire.
D. Cannot adjust 1. Check hot water
water thermistor.
temperature. (outgoing
thermistor)
2. Check
changeover solenoid
valve (SV3).
3. Check
modulating valve.
4. Check water flow-
servo.
(cont.)
Diagnostic Point
1. Measure the voltage 5 ~ 150 VAC
between flame rod
terminal C and
1
appliance ground.
Is it secure?
2. Check to ensure flame
rod bracket is not loose.
Are connections
Check for faulty ground
OK?
wire connections at unit,
receptacle, and ground
rod to home, and for
broken or shorted wires.
# Disconnect connector Resistance values
B and measure the match table on page
5
#43
resistance between
white ~ white.
(See page 43)
1. # Disconnect 1.7 ~ 2.1KΩ
connector E from PCB
and measure the
resistance between
brown ~ black.
80 ~ 100 VDC
2. Measure the voltage
between brown ~ black
wire of the changeover
solenoid valve (SV3) at
connector E.
(See page 41)
1. # Disconnect 67 ~ 81Ω
modulating valve at C
2
festoon terminal and
measure resistance at
solenoid terminals.
(See page 44)
2 ~ 15 VDC
2. Measure the voltage
between two harness
terminals at C .
2
(See page 44)
3. Check whether the
Does the manifold
manifold pressure alters
pressure change?
when remote control
temperature is altered
between 96° ~ 140°F.
1, # Measure resistance 22 ~ 26Ω
between red ~ blue
wires of the water flow
servo connector B .
2
(See page 44)
34
Values Y/N
Yes Go to C-1-2
No Replace PCB
Go to C-2
Yes
Replace/
No
rectify
Check for
Yes
other causes
of flame
failure.
Replace or
No
repair
grounding
circuit to unit.
Yes Go to D – 2
No Replace water
temperature
thermistor.
Yes Go to D – 2-2
No Replace
manifold
assembly
Yes Go to D – 3
No Replace PCB
Yes Go to D – 3-2
No replace gas
valve
Yes Go to D – 3-3
No Replace PCB
Yes
Go to D – 4
No
Replace gas
valve
Yes Go to D – 4-2
No Replace water
flow servo
sensor.
Service
Action Procedure
IGI – 2
IGI – 6
IGI – 8
IGI – 2
IGI – 9
IGI – 2
IGI – 9
IGI – 3