1What is the purpose of the transformer used on liquied level controls?
Isolate line voltage potential from ground
2Liquid Level controls operate based on the principle that an electric current can flow through what?
Water
3What is the one major downfall of a single proble electro-machanical liquid level control?
Fast cycling as soon as the water uncovers the probe
4How did adding a second probe to the control system correct this downfall?
Created a differental between the cut off and cut on levels
5What problem can a dirty or loose ground connection make in the operations of the liquid level control?
Intermittent operation, or overflow conditions
6What will happen if the connection to the short probe breaks?
Unit will overflow
7What happens if the connections to the long proble breaks?
Unit reverts back to single prob operation
8What happens if the short probe shorts to ground?
Unit will not flow
9What will occur if the long proble shorts to ground?
Unit will fill once when power is energized, then not fill again
10What would happen if the relay coil opens?
Overflow
11What would happen if the tank became heavily scaled over its internal surfaces?
Overflow
12What would happen if the normally open contacts on the control failed to make contact when they closed?
Operate as a single probe unit
13Give five possible causes for a machine using a liquid level control to overfill?
Scale build up, bad ground, relay coil opens, scaled short probe, broken wire, de-ionized water
14 Give five possible causes for a machine using a liquid level control to fail to fill?
Water turned off, bad fill valve, shorted short probe, shorted wire to short probe, faulty control
15If a tank fills one time and then will not refill again until the power is switched off and back on, where is the problem?
Shorted long probe circuit
16Why does a solid state liquied level control need only a single probe?
Built in time delay to prevent short cycling
17If you did find a solid state level control with two probes, what does the second probe indicate?
Low water cutoff
18If a solid state liquid level control has no terminal on the board indicated for a ground wire, where will it obtain its ground connection?
Form the mounting screw connections
19What effect will de-ionized water have on the operation of a ;liquid level control system?
Overflow, current will not flow through the water