1. Introduzione
This manual provides essential information for the safe and effective installation, operation, and maintenance of the Danfoss KP 35 Low Current Pressure Switch. The KP 35 is designed for use in various applications including refrigeration, air conditioning, and general industrial systems, monitoring and controlling pressure within a specified range.
2. Informazioni sulla sicurezza
AVVERTIMENTO: Improper installation, operation, or maintenance can result in serious injury or equipment damage. Always follow these safety guidelines:
- Ensure power supply is disconnected before installation or servicing.
- L'installazione e la manutenzione devono essere eseguite esclusivamente da personale qualificato.
- Verify that the pressure switch specifications match the system requirements.
- Do not exceed the maximum rated pressure or temperature.
- Protect the switch from physical damage and environmental extremes.
3. Prodotto finitoview
The Danfoss KP 35 pressure switch is a compact, robust control device featuring a single-pole double-throw (SPDT) contact system. It is designed for regulating, monitoring, and alarm systems in industrial applications. The switch is equipped with a pressure connection and electrical terminals for easy integration into control circuits.

Figura 3.1: Fronte view of the Danfoss KP 35 pressure switch, displaying the adjustable range and differential scales, along with the Danfoss logo and "INSTRUKART" branding.

Figura 3.2: lato view of the Danfoss KP 35 pressure switch, highlighting the pressure connection port at the bottom and the electrical conduit entry on the side.
4. Specifiche
| Caratteristica | Dettaglio |
|---|---|
| Marca | Danfoss |
| Modello | 35° piano |
| Modalità di funzionamento | Elettrico |
| Tipo di terminale | SPDT (singolo polo doppio lancio) |
| Valutazione internazionale di protezione | Grado di protezione IP54 |
| Specifica Met | CCC, CE, RoHS |
| Protocollo di connettività | X-10 |
| Campo di pressione | da -0.2 a 7.5 bar |
| Intervallo di temperatura | Da -40 °F a 149 °F (da -40 °C a 65 °C) |
| Dimensione della connessione | 1/2 pollici |

Figure 4.1: Danfoss KP 35 pressure switch shown alongside a ruler, providing a visual reference for its physical dimensions. Mounting screws and washers are also visible.

Figure 4.2: Technical drawing illustrating the dimensions of the Danfoss KP 35 pressure switch, including height, width, and depth, along with connection details.
5. Installazione
5.1 Montaggio
- Select a suitable location free from excessive vibration, moisture, and extreme temperatures.
- Mount the switch using the provided mounting holes. Ensure it is securely fastened.
- The switch can be mounted in any position, but vertical mounting with the pressure connection downwards is generally recommended to prevent accumulation of liquids in the pressure connection.
5.2 Collegamento di pressione
- Connect the pressure switch to the system's pressure line using the 1/2 inch connection.
- Use appropriate sealing material (e.g., PTFE tape) to ensure a leak-free connection.
- Avoid overtightening the connection to prevent damage to the switch or piping.
5.3 Cablaggio elettrico
ATTENZIONE: Disconnect all power before performing electrical wiring.
- Remove the cover of the switch to access the electrical terminals.
- Connect the electrical wires according to the system's wiring diagram and local electrical codes. The KP 35 features SPDT contacts.
- Assicurarsi che tutti i collegamenti siano sicuri e adeguatamente isolati.
- Replace the cover securely after wiring.

Figura 5.1: Interno view of the Danfoss KP 35 pressure switch with the cover removed, revealing the electrical terminals and contact mechanism. This view is crucial for wiring connections.
6. Installazione e regolazione
The KP 35 pressure switch allows for independent adjustment of the cut-in pressure (range) and the differential pressure.
- Adjusting the Range (Cut-in Pressure): Use the larger adjustment screw or knob (typically marked "RANGE") to set the desired cut-in pressure. This is the pressure at which the switch will activate or deactivate.
- Adjusting the Differential: Use the smaller adjustment screw or knob (typically marked "DIFF") to set the differential pressure. This is the difference between the cut-in and cut-out pressures. For example, if the range is set to 5 bar and the differential to 1 bar, the switch will cut in at 5 bar and cut out at 4 bar (for a decreasing pressure application).
- Refer to the scales on the front of the switch for precise settings.
- After adjustment, verify the settings by observing the system's pressure and the switch's operation.
7. Istruzioni per l'uso
Once installed and adjusted, the Danfoss KP 35 pressure switch operates automatically based on the system pressure. When the pressure reaches the set cut-in point, the SPDT contacts will switch position. When the pressure changes by the set differential, the contacts will switch back.
- Monitor system pressure to ensure it remains within the safe operating limits of both the switch and the overall system.
- Observe the electrical load connected to the switch to ensure it does not exceed the switch's rated capacity.
8. Manutenzione
The Danfoss KP 35 pressure switch is designed for long-term, reliable operation with minimal maintenance. However, periodic checks are recommended:
- Ispezione visiva: Ispezionare regolarmente l'interruttore per individuare eventuali segni di danni fisici, corrosione o collegamenti allentati.
- Controlli delle perdite: Controllare periodicamente il collegamento di pressione per verificare la presenza di eventuali perdite.
- Test funzionale: If possible and safe, periodically test the switch's operation by simulating pressure changes to ensure it activates and deactivates at the set points.
- Pulizia: Mantenere l'esterno dell'interruttore pulito e privo di polvere e detriti. Non utilizzare prodotti chimici aggressivi.
9. Risoluzione Dei Problemi
If the pressure switch is not functioning as expected, consider the following common issues:
| Problema | Possibile causa | Soluzione |
|---|---|---|
| L'interruttore non si attiva/disattiva | Incorrect pressure settings; No power; Faulty wiring; Clogged pressure line; Internal switch failure. | Verify range and differential settings; Check power supply; Inspect wiring for loose connections or breaks; Clear pressure line; Replace switch if internal failure is suspected. |
| Funzionamento incoerente | Pressure fluctuations in the system; Vibration; Loose mounting. | Stabilize system pressure; Isolate switch from vibration; Securely fasten mounting. |
| Perdita nel collegamento di pressione | Improper sealing; Damaged threads. | Re-apply sealing material (e.g., PTFE tape); Inspect threads for damage and repair or replace if necessary. |
10. Garanzia e supporto
For specific warranty information and technical support, please refer to the official Danfoss webo contattare il distributore Danfoss autorizzato. Conservare la ricevuta d'acquisto per eventuali reclami in garanzia.
Danfoss ufficiale Websito: www.danfoss.com





