Dual Level Control
Auto Refill And Low Water Cutoff System
I)Dual Level Control: What it does:
A.AUTO REFILL of the water compartment to keep the tank filled with water. When water is used, the fill valve opens automatically to let
in more. The fill valve closes when the water level reaches full.
B.LOW WATER CUTOFF to prevent burn out of the electric immersion heater when there is not enough water to cover it. When low water occurs, the heat automatically switches off. The heat stays off until more water is added.
C.A device called a DUAL LEVEL CONTROL keeps the tank filled with water and turns off the heat when water is low by simultaneously monitoring two different water levels.
II)Description and Operation of Dual Level Control System: A. Components
1.DUAL LEVEL CONTROL - switches power to both the thermostat and water inlet solenoid valve by sensing changes in water level.
FILL HEAT | M | N |
| 120VAC | |
|
| TRANSFORMER |
RELAYS |
| PRINTED CIRCUIT |
PROBES | ||
HI | XL | C |
2.ELECTRODE ASSEMBLY - consists of a high (short) and a low (extra long) sensing electrode, or probe, molded in an epoxy body.
RED WIRE
| GREEN WIRE | GREEN WIRE |
|
| |
HIGH | LOW | RED WIRE |
|
| |
TOP MOUNTED PROBES | SIDE MOUNTED PROBES | |
3. METAL ENCLOSURE | - provides a common (ground) connection for the | |
(TANK BODY) | electrode circuit. | |
HIGH
LOW
|
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American Metal Ware Hot Water Boiler | Page 6 |
