Italtecnica PSD5 pressure switch with changeover contact, 1.7–7.5 bar, 1/4" swivel nut

The Italtecnica PSD5 (PS series) is a mechanical pressure switch with a volt-free changeover contact (COM, NO and NC) for control circuits up to max. 5 A / 250 V. It works purely on the system pressure and needs no power supply of its own. The setting range is 1.7 to 7.5 bar. From the factory, the PSD5 switches in at 2.4 bar and out at 3.5 bar.

You use the PSD5 signal for a controller, relay, contactor or alarm. Thanks to the changeover contact, you choose the operating mode yourself: normal (contact closes at low pressure and opens at high pressure) or inverted (contact closes at high pressure). In inverted mode you can, for example, trigger an alarm or valve as soon as the pressure gets too high, or control a drain or fill pump. This makes the PSD5 suitable for pressure monitoring, pressure boosting systems, water treatment and fire-fighting installations.

Note: the PSD5 is a control-circuit switch and not a replacement for a pump pressure switch such as the PM5. A pump motor is switched via a relay or contactor.

How to set the PSD5:

• 1. First switch off the control circuit. The switch can carry up to 250 V.
• 2. Undo the screw on top of the cover and remove the cover. You will see two springs: a large one and a small one.
• 3. The large spring sets the lower switching point (2.4 bar from the factory). Turn the nut on the large spring clockwise (tighter): the contact changes over at a higher pressure. Anticlockwise (looser): the contact changes over at a lower pressure. Note: the large spring also moves the upper switching point up or down with it.
• 4. The small spring sets how much higher the contact switches back (3.5 bar from the factory). This gap is called the "differential". Turn the nut on the small spring clockwise: the gap gets bigger. Anticlockwise: the gap gets smaller.
• 5. Turn half a turn to one full turn at a time, refit the cover and read on the pressure gauge at which pressure the contact changes over. You can see this on the connected relay or alarm, or with a multimeter. Repeat until the values are right.

The membrane is NBR rubber with a textile insert, and the protection class is IP44. The pressure connection is a 1/4" female thread with a swivel nut and gasket. You don't need to turn the switch itself, and no PTFE tape is needed. Have the electrical connection made by a qualified person.

This product is supplied without a cable!