C D S       PRODUCTS
OIL     PRESSURE      SWITCHES
HOW THEY WORK
BEFORE STARTING THE ENGINE

All C.D.S. Pressure Switches are diaphragm operated. Fluid pressure, acting on one side of the diaphragm, overpowers a spring force and moves the diaphram and its attached parts to one extreme of its travel where it is solidly backed by metal. Thus it can withstand a great amount of overpressure. When pressure fails, the precision spring moves the diaphragm assembly back to its normal position and produces the switching action.

A set spring is provided on C.D.S. Pressure switches to hold the switch in the run position during starting when the engine has no oil pressure. Prior to cranking, the set spring is engaged into the recess on the housing of the switch by pulling out on the hex nuts and pushing the end of the set spring into the groove. The engine can now be started. The set spring will snap out of the groove when oil pressure has built up and the pressure will hold the switch in the run position. The operator must verify that this has happened. It is possible, without verification, that the set spring is still engaged and is allowing the engine to run without oil pressure.





The precision spring installed at the factory determines the setting of the switch, therefore they cannot be readjusted in the field to too low a setting thereby voiding the protection the purchaser intended. Except for Types D and F, the contacts of the switches are immersed in the operating fluid, making the switches suitable for use in places where explosive gases are present. All C. D.S. Pressure Switches are 100% tested for operation and for agreement between the switching pressure and the setting as marked on the switch housing. This is maintained within very close limits.

In some cases when other means have been provided for starting or when the pressure switch is used as a sender, the set spring is not required. In order to prevent the possibility mentioned above, all C.D.S. Pressure switches can be supplied without the set spring and with a shorter, flush tail piece. These are specified by adding an "S" suffix to the type of switch and/or adding 5 to the series number. Example: Type RS set at 8 PSI = P/N 9105 -80; Type HS set at 12 PSI = P/N 9405 -120


AVAILABLE PRESSURE SETTINGS

Pressure Switches are made in the pressure settings shown on the chart below:

Pressure Switches are made in the settings shown on the chart below:
  
Series
Series
Series
Series
Series
  
9100
9170
9200
9300
9400
0.9  PSI
*
  
*
*
  
1.0  PSI
*
  
*
*
  
1.5  PSI
*
  
*

*
  
2     PSI
*
  
*

*
  
3    PSI
*
  
*
*
  
6    PSI
*
*
*
*
*
  8    PSI  
*
  
*
*
*
10   PSI  
*
*
*
*
*
12   PSI  
*
  
*
*
*
15   PSI  
*
  
*
*
*
18   PSI  
*
  
*
*
*
20   PSI  
*
  
*
*
*

Consult the equipment manufacturer's recommendations when specifying the setting of the pressure switch.

Too high a setting could lead to needless shut downs.

Too low a setting could result in no protection.

The 6 PSI setting, being the most popular, will be shipped when no setting is specified. This is not to be taken as a recommendation because we have no way of knowing the characteristics of the equipment on which it will be used.

The pressure setting in tenths of a PSI follows the series number and is separated by a hyphen to complete the part number of a particular pressure switch. Example: A SERIES 9100 switch set at 6 PSI = P/N 9100-60.
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