'POINTER' pressure switches are designed to be weather tight for external use. They are built to stand up to the rigors of environment and provide long lasting and dependable service. Diaphragm type switches are recommended for most process applications while pivot seal type weatherproof pressure switches perform best in fluid power (Hydraulic) applications.

This control is a precision instrument and should never be left with internal components exposed. During installation insure that covers are in place and conduit opening sealed.

When tightening to pressure line, always use the wrench flats or hex on the pressure connection, never tighten by twisting the case. An optional pipe mounting bracket is also available.

The pressure in the pressure capsule is converted into force by means of a reinforced rubber / metal diaphragm and a calibrated piston, which is balanced by a compression spring from above. When the force generated by the pressure in the pressure capsule exceeds/faills beyond the balancing force, an electrical element is actuated througha bell crank lever mechanism for switching. Please use the pressure/vaccume/pressure difference as also the electrical parameters.

• Remove the top cover.
• Pass the cable through the cable gland (usually provided with switch) and connect the wiring as per the wiring diagram. The wiring code is as per the details given below.
• Terminal 1 : (C) Common
• Terminal 2 (NC) Normally Closed
• Terminal 3 (NO) Normally Open

Ensure the supply is off, before setting the switch. Status of contacts can be checked with a multimeter / continuity tester. (A) For switches with fixed differentials

• Remove the cover. The retaining screws are engaged in the cover, just loosening them should unfasten the cover.
• Adjust the desired set point on the scale.
• Apply the desired cutting (lower) / cutout (higher) pressure to the pressure switch.
• Some minor adjustment will be required to achieve the exact cut in (lower) / cutout (higher) point, which can be checked with the help of a proper pressure / vacuum measurement device.
• Replace the cover and tighten the screws.

Generally no problems are observed if the pressure switch selection, wiring and the setpoint is proper. For a pressure switch selection procedure, please consult our sales office. For properly selected pressure switches, if following symptoms are observed, the likely causes and remedies are as stated below.

• Switch does not operate : Wiring may not be correct. Check electrical connections to the pressure switch, if they are as per the wiring diagram.
• Pressure does not reach the pressure port : Check if the entry to the pressure capsule is not blocked by frozen process or scales or impurities in the process. If this is the case, try freeing the blocked path by a blunt tool in case of scales or impurities.
• Do not open the pressure capsule if observed, the pressure switch should be returned to factory for calibration & re-set.

Isolate the switch electrically. Check the continuity between terminals and the screws fitted to the body. If no continuity is observed in between any of the terminals and screws fitted to the body, check the short connection elsewhere in the circuit. If continuity is observed, the wires of the pressure switch have internally touched the body, and the switch should be returned to the factory.

• Check the system pressure for surges. Chattering is observed where the system pressure is close to the cut in / cutout point and the surge pressure exceeds the on-off differential. Use a pressure switch with an adjustable differential of use surge dampers in your system.
• If there is a relay in the circuit, check if the relay is properly plugged in. Chattering may be due to loose contact.