Important Safety Notes
There are a number of (live) tests that are required when fault
finding this product. Extreme care should be used at all times
to avoid contact with energized components inside the water
heater. Only trained and qualified service technicians should
attempt to repair this product. Before checking for resistance
readings, disconnect the power source to the unit and isolate
the item from the circuit (unplug it).
TROUBLESHOOTING
0-2000 ft
(0-610 m)
Switch No. 2
Switch No. 3
2001-5400 ft
(610-1646 m)
OFF
OFF
OFF
ON
SWITCH
SWITCH
Set dip switches 2 and 3 to the values shown in table below for your altitude.
The default setting for the appliance is 0 - 2000 ft (0 - 610 m) with switches
No. 2 and No. 3 in the OFF position.
Thermistors:
Check all thermistors by inserting meter leads into each end
of the thermistor plug. Set your meter to the 20 K scale and
read resistance. Applying heat to the thermistor bulb should
decrease the resistance. Applying ice to the thermistor bulb
should increase the resistance. See below for examples of
typical temperatures and resistance readings.
With the power off you can check the continuity through the
surge protector. Place a meter lead on the top pin #1 of the
surge protector and pin #3 on the bottom of the surge protec-
tor. Check across the top pin #3 and bottom pin #1. If you read
continuity across these two points then the surge protector is
good. If you do not get continuity then replace the surge
protector.
Amp Fuses:
This unit has one inline (5) amp glass fuse. Remove the fuse
and check continuity through it. If you have continuity through
the fuseB then it is good. Otherwise the fuse is blown and
Wire Color
Voltage
Resistance Connector
#
Pin #’s
Tank Temperature Thermistor (White & Yellow at the PCB)
White - White
N/A
See Chart
Above
A2
(A) 3 - (A)
4
Heat Exchanger Temperature Thermistor
(Brown & Yellow at the PCB)
White - White
N/A
See Chart
Above
A3
(A) 7 - (A)
8
Burner Sensor Temperature Thermistor
(Pink & Grey at the PCB)
Black - Black
N/A
See Chart
Above
A4
(A)10 -
(A)11
Surge Protector:
Blue - Brown
108 ~ 132
VAC
N/A
I1
(I)1 - (I)3
Black White
108 ~ 132
VAC
N/A
I2
N/A
(SV1, SV2 and POV) Gas valve and Modulating solenoids
(Set meter above 2K)
Wire Color
Voltage
Resistance Connector
#
Pin #’s
(Main) Pink -
Black
11 ~ 13
VDC
39 ~ 44 ohms
F6
(F) 6 - 7
(SV1) Blue -
Black
11 ~ 13
VDC
35 ~ 41 ohms
F7
(F) 5 - 6
(SV2) Yellow -
Black
11 ~ 13
VDC
39 ~ 44 ohms
F8
(F) 4 - 6
(POV) Orange -
Orange
2 ~ 15 VDC 65 ~ 85 ohms F2 & F3 (F) 9 - 10
(M) Water Flow Control Servo or Geared Motor
6
-
5
)
G
(
A
/
N
k
n
i
P
-
d
e
R
Red - Orange
N/A
(G) 5 - O
4
-
3
)
G
(
A
/
N
e
ti
h
W
-
e
u
l
B
Blue - Orange
N/A
(G) 3 - O
Grey - Yellow
N/A
GY - (G)1
2
)
G
(
-
Y
G
A
/
N
n
w
o
r
B
-
y
e
r
G
(QS) Water Flow Sensor:
Red - Black
11 ~ 13
N/A
(A) 9 - 5
Yellow - Black 4 ~ 7 VDC
N/A
(A) 1 - 5
Note: Red turns to Orange and Black turns Grey on the PCB.
(IG) Ignition System
Grey - Grey
90 ~ 110
N/A
H1
(H) 1 - 2
(FM) Combustion Fan Motor:
Red - Black
7 ~ 45 VDC
N/A
(B) 1 - 2
Yellow - Black
11 ~ 13
N/A
(B) 3 - 2
White - Black
7 ~ 45 VDC
N/A
(B) 4 - 2
(FV) Flammable Vapor Sensor:
Red - Black
1.9 ~ 2.1
N/A
(D) 1 - 6
White - Yellow 25.5 ~ 39.5
mVDC
N/A
(D) 4 - 3
(COS) Carbon Monoxide Sensor:
Red - Black
1.9 ~ 2.1
N/A
(C) 1 - 5
Blue - Yellow
29 ~ 31
mVDC
N/A
(C) 4 - 3
Thermal Fuse / Overheat Switch
White - White
11 ~ 13
VDC
Below 1 ohm
A6 F1 (F) 12 -
(A) 6
Note: White turns to red on the PCB
C1
5 ~ 7 VDC
G1
4 ~ 6 VDC
A1
B1
D1
