Italtecnica PT5 pressure switch 230/400 V, 16 A, 1–5 bar, 1/4" swivel nut

The Italtecnica PT5 is a mechanical pressure switch for booster sets. Unlike the PM5, the PT5 is a three-pole switch, so it suits both single-phase 230 V and three-phase 400 V pumps up to max. 16 A. It starts the pump when the pressure drops and stops it again once the set pressure is reached. The switching pressure is adjustable between 1 and 5 bar. From the factory, the PT5 is set to 1.4 bar on and 2.8 bar off.

The pressure connection is a 1/4" female thread with a swivel nut and gasket. You don't need to turn the switch itself: you screw the nut onto the 1/4" male thread of, for example, a 5-way connector, and the gasket makes the seal. No PTFE tape is needed. Have the electrical connection made by a qualified person, especially on 400 V.

How to set the PT5:

• 1. First switch off the circuit breaker or isolator of the pump. The switch carries 230 V or 400 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 when the pump switches on. Turn the nut on the large spring clockwise (tighter): the pump switches on sooner, at a higher pressure. Anticlockwise (looser): the pump switches on later, at a lower pressure. Note: the large spring also moves the cut-out pressure up or down with it.
• 4. The small spring sets how much higher the pump switches off. This gap is called the "differential". Turn the nut on the small spring clockwise: the pump switches off at a higher pressure, so the gap gets bigger. Anticlockwise: the pump switches off sooner, so the gap gets smaller.
• 5. Turn half a turn to one full turn at a time, refit the cover, switch the power back on and read on the pressure gauge at which pressure the pump starts and stops. Repeat until the values are right.
• 6. Set the pressure vessel pre-charge 0.2 to 0.3 bar below the cut-in pressure. For example, if the pump starts at 2.0 bar, set the vessel to 1.7–1.8 bar.

A gap of 1 to 1.5 bar between on and off works well for most domestic installations.

This product is supplied without a cable!