Condensing Models: On-Demand Water Heater Service Handbook • 15
TR
OUBLE
SHOO
TING
3. If the unit was recently rebuilt,
make sure that each gas valve wires
are plugged into the proper place.
4. Verify that the supply gas pressure
is within the specified limits. Too
high of an inlet gas pressure may
cause the main gas valve to jam or
could be damaged.
5. Check the voltage across each
solenoid gas valve wire during
operation. The blue wire is
common.
•
SV1: Green, #9
•
SV2: Orange, #53
•
SV3: Red, #73
The voltage reading should be
93-120 VDC. If the voltage is not
within normal range, replace the
computer board, part number
320273-369.
6. With the power off, check the
resistance of the valve. Normal
resistance reading for SV1 and SV2
is 1.35-1.65 k
Ω
. Normal resistance
reading for SV3 is 2.07-2.53 k
Ω
.
If the resistance is out of range,
replace the gas valve, NG: part
320273-356, LP: part 320273-354.
Abnormal Fan Motor
Error Code: 611
1. Turn off power supply.
2. Check fan motor wiring for
breakages, burn marks on the
computer board (PCB), or moisture.
If moisture is found, allow the
connection to dry completely
before turning power back on.
3. Check fan housing for water. If
found, please dry the fan, then
test heater. If there is a significant
amount of water, there may be a
heat exchanger leak.
4. To remove the fan, follow steps
1 through 10 in ““Removing Heat
Exchanger Components (Indoor
Models)” (p. 37). When you are
finished, reassemble in reverse
order.
5. If the 611 error code still appears after
all items have been checked, the PCB
may need replacement. Contact the
technical service department.
TABLE 3: RESISTANCE VALUES OF THE TEMPERATURE THERMISTORS INDOOR AND OUTDOOR MODELS
TEMPERATURE
°F
32
41
50
59
68
77
86
95
104
113
°C
0
5
10
15
20
25
30
35
40
45
RESISTANCE
K
Ω
23.76
19.08
15.43
12.56
10.28
8.47
7.02
5.85
4.90
4.12
TEMPERATURE
°F
122
131
140
149
158
167
176
185
194
203
212
°C
50
55
60
65
70
75
80
85
90
95
100
RESISTANCE
K
Ω
3.49
2.96
2.53
2.16
1.86
1.60
1.39
1.21
1.05
0.92
0.81
TABLE 4: RESISTANCE VALUES OF THE TEMPERATURE EXHAUST THERMISTOR INDOOR MODELS ONLY
TEMPERATURE
°F
32
41
50
59
68
77
86
95
104
113
°C
0
5
10
15
20
25
30
35
40
45
RESISTANCE
K
Ω
30.04
24.12
19.50
15.87
13.00
10.71
8.87
7.39
6.19
5.21
TEMPERATURE
°F
122
131
140
149
158
167
176
185
194
203
212
°C
50
55
60
65
70
75
80
85
90
95
100
RESISTANCE
K
Ω
4.41
3.74
3.19
2.73
2.35
2.03
1.76
1.53
1.33
1.16
1.02