Service manual

32
Nature of Fault
Examination
Point Diagnostic Point Values Y/N Action
Service
Procedure
C
. Combustion
occurs, but flame
f
ails.
Error code "12"
displayed on
digital monitor.
1
. Check flame rod.
2. Check ground
wire.
1
. Measure the voltage
between flame rod
t
erminal C
1
a
nd
appliance ground.
2. Check to ensure flame
rod bracket is not loose.
Check for faulty ground
wire connections at unit,
receptacle, and ground
rod to home, and for
broken or shorted wires.
5
~
1
50 VAC
I
s it secure?
Are connections
OK?
Y
es
No
Y
es
No
Yes
No
G
o to C-1-2
Replace PCB
Go to C-2
Replace/
rectify
Check for
other causes
of flame
failure.
Replace or
repair
grounding
circuit to unit.
I
GE – 2
D. Cannot adjust
water
temperature.
1. Check hot water
thermistor.
(outgoing
thermistor)
# Disconnect connector
B
5
and measure the
resistance between
white
~
white.
(See page 41)
Resistance values
match table on page
#41
Yes
No
Go to D – 2
Replace water
temperature
ther
mis
tor.
IGE – 6
2. Check
changeover solenoid
valve (SV3).
1. # Disconnect
connector E from PCB
and measur
e the
resistance between
brown
~
black.
(See page 39)
2. Measure the v
olt
age
between brown
~
black
wir
e of the changeover
solenoid valve (SV3) at
connector E.
(See pag
e 39)
1.7
~
2.1KΩ
80
~
100 VDC
Yes
No
Yes
No
Go to D – 2-2
Replace
manif
old
assembly
Go t
o D – 3
Replace PCB
IGE – 8
IGE – 2
3. Check
modulating valve.
1. # Disconnect
modulating valve at C
2
festoon terminal and
measure resistance at
solenoid t
er
minals.
(See page 42)
2. Measure the voltage
between two harness
terminals at C
2
.
(See page 42)
3. Check whether the
manif
old pr
essure alters
when remote control
temperature is altered
betw
een 96°
~
1
40°F
.
67
~
8
1Ω
2
~
1
5 VDC
Does t
he manif
old
pressure change?
Yes
No
Yes
N
o
Yes
N
o
Go t
o D – 3-2
replace gas
valve
Go to D – 3-3
Replace PCB
Go to D – 4
Replace gas
valve
IGE – 9
IGE – 2
IGE – 9
4. Check water flow
serv
o.
1
, # Measure resistance
between red
~
blue
wir
es of t
he w
at
er flow
servo connector B
2
.
(See page 42)
22
~
26Ω
Y
es
No
Go t
o D – 4-2
Replace water
flow servo
sensor
.
IGE – 3
VI - TROUBLESHOOTING (cont.)
Troubleshooting Flow Chart
BEFORE CARRYING OUT CHECKS MARKED WITH
A # SIGN, DISCONNECT THE POWER SUPPLY.