This page is important to understand!

 

The Wetwell has two pumps in it.  One pump has enough pumping capacity to pump the sewage from Paniolo Hale to the Hotel.  But under full occupancy circumstances, or a pump failure, a second pump is needed.  The operation of these pumps is controlled by float switches. 

      There are four green float switches.  If you look carefully you can see all four of them:

 

This one is floating (laying sideways).  It is the OFF float switch (explained below).

This one is tough to see, but it is the next highest float switch.  When the level rises, it will float and send a signal to the control panel to turn on the first pump.  This will make the level in the wetwell go down until the OFF float switch hangs, rather than floats.  The first pump will then shut off.

Note that these two float switches are hanging.  They are set higher than the other two.  The highest one is the ALARM float switch.

READ THIS OPERATION CAREFULLY:

If the wetwell was empty, all four float switches would hang (not float).  As sewage enters the wetwell, the level rises.  It will continue to rise until the OFF float switch floats, and continue even higher until the second float switch floats (the one hard to see).  The first pump will turn on and pump the sewage into the Force Main.  The level will then drop until the OFF float switch hangs, as explained above, turning off the pump. 

    See how clean the other two float switches are?  Ideally, they should never float, because the level should never get that high.  But if it does reach the third float switch, the second pump will turn on (usually due to a failure of the first pump).  If both pumps fail, the level continues to rise until the ALARM float switch floats.  This will send a signal to the Control Panel to sound the alarm.

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