Go to, Thermostat, Troubleshooting – American Water Heater DCG User Manual
Page 25: FLow chart, Dcg3 series thermostat troubleshooting flow chart
DCG3 SERIES
THERMOSTAT TROUBLESHOOTING FLOW CHART
Copyright© by American Water Heater Company 2005. All rights reserved.
FCG3-0805
No voltage or
low voltage from
purple wire
between
thermostat board
& ECO board
Replace
bad
sensor(s)
Replace
ECO board
With an ohm meter
set at X1, check
orange wires on
set pot. (3,000 ohms
at lowest setting and
0 ohms at highest
setting)
Replace
set pot
When slowly turning
set pot dial from low
to high, ohm reading
should be a smooth
transition with no
skips, jumps or
glitches
Take ohm reading
from upper sensor
and lowest sensor and
compare reading with
chart below.
(A temperature
reading from a water
sample taken from
T&P valve is also
needed for this test)
Check purple wire
from thermostat
for 24V
Check orange wire
from ECO board to
damper for 24V
Check
damper
Replace
thermostat
circuit
board
Is ECO light on?
Check ECO
and ICM
Will ECO board
reset?
High water
temperature
NO
HAS
BAD SPOT
OHMS OK
NO
OHMS
READING
NO GOOD
YES
NO
NO
YES
NO
YES
YES
OK
0°C 32648 31026 29495 28049 26682 25389 24166 23010 21915 20879
10°C 19898 18968 18088 17253 16461 15710 14998 14322 13680 13071
20°C 12492 11942 11419 10922 10450 10000
9572
9165
8778
8409
30°C
8057
7722
7403
7099
6808
8532
6268
6016
5775
5546
40°C
5327
5117
4917
4726
4543
4368
4201
4042
3889
3742
50°C
3602
3468
3340
3217
3099
2986
2878
2774
2675
2579
60°C
2488
2400
2316
2235
2157
2083
2011
1942
1876
1813
70°C
1752
1693
1637
1582
1530
1480
1432
1385
1340
1297
80°C
1256
1216
1177
1140
1105
1070
1037
1005
974
944
90°C
916
888
861
835
810
786
763
741
719
698
40°F 26109 25400 24712 24045 23399 22771 22163 21573 21000 20445
50°F 19906 19383 18876 18383 17905 17440 16990 16553 16128 15715
70°F 11884 11592 11308 11032 10763 10502 10248 10000
9760
9526
90°F
7333
7165
7000
6839
6683
6531
6383
6238
6098
5961
100°F
5827
5697
5570
5446
5326
5208
5094
4982
4873
4767
120°F
3758
3679
3602
3527
3453
3382
3312
3244
3177
3112
140°F
2488
2439
2391
2344
2298
2253
2209
2166
2124
2083
160°F
1688
1656
1625
1595
1566
1537
1509
1481
1454
1427
180°F
1170
1150
1129
1110
1090
1071
1053
1035
1017
999
190°F
982
965
949
933
917
901
886
871
857
842
200°F
828
814
801
788
775
762
749
737
725
713
Temp.
0
1
2
3
4
5
6
7
8
9
Resistance (K ohms)
Sensor Resistance vs. Temperature
Index