Advertisement
TABLE 2—THERMISTOR RESISTANCE AT VARIOUS TEMPERATURES IN CELSIUS.
Temp-
erature
(°C)
0
0
32648
31026
10
19898
18968
20
12492
11942
30
8057
7722
40
5327
5117
50
3602
3468
60
2488
2400
70
1752
1693
80
1256
1216
90
916
L8104A,D
When the temperature at the sensing bulb drops below
the setting on the potentiometer, the relay contacts in the
electronic control module make to open the gas control or
turn on the ignition module. When the temperature rises to
the setpoint, the relay contacts open, closing the gas control
or turning off the ignition module.
The control circuit is accurate to within ±3.5°F (±1.9°C)
at maximum setpoint. (180°F (83°C) setpoint controls are
accurate within +7°F (+3.8°C), -0°F (0°C).
L8104B,C
Operation of the L8104B,C is similar to L8104A,D ex-
cept the electronic control module opens and closes the
relay in response to the average of the temperatures sensed
by the upper and lower sensing bulbs.
ECO LIMIT OPERATION
If the temperature at the ECO switch rises above the
ECO limit setting, the contacts in the ECO switch break and
turn off the water heater.
1
2
3
29495
28049
18088
17253
11419
10922
7403
7099
4917
4726
3340
3217
2316
2235
1637
1582
1177
1140
888
861
835
SETTING AND CHECKOUT • OPERATION
Resistance (K ohms)
4
5
26682
25389
24166
16461
15710
14998
10450
10000
9572
6808
8532
6268
4543
4368
4201
3099
2986
2878
2157
2083
2011
1530
1480
1432
1105
1070
1037
810
786
L8104A,B
The L8104A,B uses a recycling ECO switch that re-
makes once the temperature drops below the ECO tempera-
ture. Before the system will restart, however, the system
must be reset. On a standing pilot system, the pilot must be
relit. On an electronic ignition system, power to the 100
percent lockout ignition module must be off for one minute.
A nonrecycling (one-shot) ECO switch will not remake.
The sensing bulb containing the switch must be replaced.
L8104C,D
The L8104C,D uses a recycling ECO switch. When the
ECO opens, the red LED on the electronic module lights
and the water heater is turned off. To restart the system,
press the black manual reset pushbutton until the red LED
turns off. The ECO switch is closed and the sys-
tem is reset.
11
6
7
8
23010
21915
14322
13680
9165
8778
6016
5775
4042
3889
2774
2675
1942
1876
1385
1340
1005
974
763
741
719
Operation
68-0063—3
L8104A,B,C,D
9
20879
13071
8409
5546
3742
2579
1813
1297
944
698
Advertisement
