2. Description and Operation of Dual Level Control System (continued):
B.Operation Water Level
1) Below both electrodes
Action
1)Both “HI” and “XL” electrode circuits open. Dual Level Control turns power on to fill valve and keeps power off to thermostat.
| Fill Solenoid | Thermostat |
| Valve | OFF |
2) Rises to low electrode above | ON | |
2) “XL” electrode circuit closes. Power to | ||
above heater coils | thermostat turned on. | Power to fill valve |
| remains on. |
|
3)Rises to high electrode
4)Falls below high electrode only
Fill Solenoid | Thermostat | |
Valve | ||
|
ON ON
3)“HI” electrode circuit closes. Dual Level Control turns power off to fill valve and con- tinues power to thermostat.
Fill Solenoid | Thermostat | |
Valve | ||
|
OFF ON
4)“HI” electrode circuit opens. “XL” circuit stays closed. After a few seconds delay, power to fill valve is turned on.
Fill Solenoid | Thermostat | |
Valve | ||
|
ON ON
5) Falls below low electrode. | 5) “XL” electrode circuit now opens. Power | |
(Same as condition no. 1) | to thermostat is turned off. Power to fill | |
valve remains on. | ||
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3.Quick Service Check of Dual Level Control System:
1)All wire secure and properly connected.
2)Clean the electrodes. Lime (mineral scale)
3)Check the common (ground) connection. A little looseness or dirt can cause erratic operation.
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American Metal Ware 87710E Coffee Urn | Page 13 |