Bradford White IGI-180R-10 Service Manual page 35

VI - TROUBLESHOOTING
Troubleshooting Flow Chart
BEFORE CARRYING OUT CHECKS MARKED WITH
A # SIGN, DISCONNECT THE POWER SUPPLY.
Examination
Nature of Fault Point
E. Anti-frost 1. check anti-frost
heater does not heater.
work.
2. Check frost
sensing switch
(cont.)
Diagnostic Point
2. Measure voltage 11 ~ 13 VDC
between orange (+) and
grey (-) of the water flow
servo connector B .
2
3. Measure voltage
4 ~ 6 VDC
between brown ~ grey
of water flow servo
connector B (Don not
2
turn water on)
(See page 44)
4. Measure voltage
4 ~ 6 VDC
between yellow ~ grey
of the water flow servo
connector B (Do not
2
turn water on)
(See page 44)
1. # Disconnect 348 ~ 375Ω
connector F and F
4 5
measure resistance
across each of the
heating elements. (white
wires)
(See page 45)
2. # Read resistance of 100 ~ 110Ω
the heating element that
is mounted on the front
of the heat exchanger.
(white wires)
(See page 45)
3. Read resistance of 33 ~ 39Ω
heating elements on the
heat exchanger outlet
hot water line.
(See page 45)
# Disconnect connector Is resistance <1Ω
F and measure across after applying ice to
2
this switch for five
the bi-metal sensing
minutes?
switch located on the
upper right hand of the
heat exchanger. check
this switch at
temperatures below 37
°F. You can place an ice
cube against the switch
to activate it.
(See page 45)
35
Values Y/N
Yes Go to 4-3
No Replace PCB
Yes Go to D-4-4
No Replace water
flow servo
sensor.
Yes Normal
No Replace water
flow servo
sensor.
Yes Go to E-1-2
No Replace Anti-
frost sensing
switch.
Yes
Go to E-2
No
Replace Anti-
frost heater
that is
defective.
Yes
Go to E-2
No
Replace Anti-
frost heater
that is
defective.
Yes Check wiring
No Replace Anti-
frost sensing
switch.
Service
Action Procedure
IGI – 2
IGI – 3
IGI – 3