Compact vertically-oriented probe-style float switch — 25 mm diameter outer body fits down a 25.4 mm pipe or borehole. Vented UPVC housing with internal polypropylene float. ±1 mm switching repeatability; ideal as an alternative to conductivity probes in submersible borehole pumps.
KP Series
Level Switches
Features
- No external moving parts
- Reliable solid construction
- S.P.D.T. three-wire reed switch
- PVC, polypropylene & fluorosilicone construction
- Stable, repeatable switching action
- No mercury or lead components
- Compact 25 mm diameter — fits a 25.4 mm pipe / borehole
- ±1 mm switching repeatability
- 45 m maximum submergence (450 kPa static pressure)
- pH 1–14, UPVC and polypropylene wetted parts
- Optional cable weights available
The KP probe level switch consists of a vented UPVC housing containing a polypropylene float. Rising liquid level lifts the float and actuates a magnetically coupled reed switch within the switch head; a falling level lets the float drop, de-actuating the reed switch. The switch sensor head is CNC machined from solid UPVC and is fully potted. The switch is a high compliance single pole double throw dry contact reed switch that can switch up to 140 VAC or 150 VDC at currents up to 0.25 A resistive load, to a maximum of 5 Watts / VA. It is not suitable for use at mains voltage: it is a low voltage signalling device for BMS and PLC inputs, and an alternative to conductivity probes in submersible borehole pump installations. Must be installed vertically with its cable at the top.
More Information
Select Model
Trade customers should contact sales@kelco.co.nz for account pricing.
Ordering — Available Models
| Model Number | Description |
|---|---|
| KP-10 | KP probe switch — 10 m of CPE cable (the only length available) |
Operating Limitations
| Maximum submergence | 45 m / 450 kPa static pressure |
|---|---|
| Minimum burst pressure | 3500 kPa or 350 m static pressure |
| Maximum liquid temperature | 50 °C |
| Minimum liquid temperature | -1 °C |
| Liquid specific gravity | > 0.9 |
| Liquid pH range | 1 to 14 |
| Smallest hole/well diameter | 25.4 mm internal diameter, vertically oriented |
| Liquid level change for switch to operate | 5 mm (on to off or off to on) |
| Closest switching point to tank floor | 80 mm |
| Smallest opening through which the switch will fit | 25.4 mm diameter |
| Suitability — sea water | Fully compatible |
| Suitability — potable water | Fully compatible |
| Switching repeatability | ±1 mm liquid level change |
| Mounting orientation | Must be installed within 5° of vertical |
Electrical Data
| Switch type | Dry contact reed switch |
|---|---|
| Contact form | S.P.D.T. (single-pole double-throw) C-form, break-before-make |
| Maximum switched voltage | 140 VAC / 150 VDC |
| Maximum switched current | 0.25 A |
| Maximum switched power | 5 W / VA — IMPORTANT: the product of switching voltage and current must never exceed 5 W |
| Carry current | 1 A max |
| Breakdown voltage | 200 VDC minimum |
| Typical applications | PLC, telemetry & general low voltage control |
Dimensions
Typical Applications
Deep-well bore-pump protection (borehole installations); saline-water service; withstands most common chemicals; chemical-tank monitoring; bilge-level control; high & low level alarms; intrinsically safe circuits (simple apparatus); general-purpose liquid-level sensing.
Hazardous Areas
The KP is simple apparatus under AS/NZS 60079.11 and may be used in a hazardous area only as part of an intrinsically safe circuit, connected through suitably certified associated apparatus. It is not Ex certified in its own right. The full conditions of use are given in the installation sheet.
Safety — Low Voltage Only
The KP probe level switch is not suitable for use at mains voltage and must never be used in mains voltage applications. It is a low voltage signalling device for low voltage, low current applications only, and is ideal as an input device for BMS and PLC applications. Its reed switch suits low wetting current, low voltage control such as PLC and BMS control at 24 V, 3.3 V and 5 V, signalling and telemetry, and relay logic circuits. It is not suitable for switching inductive loads such as high wattage relays, motors of any kind or contactors. The contact power rating is the product of switching voltage and current and must never exceed 5 Watts / VA.
Mounting — vertical only
The KP probe MUST be installed vertically (within 5 degrees of vertical) with its cable at the top. It will not operate in any other orientation. It does not need to float or tilt to operate; its float is contained within the vented UPVC housing. Four mounting methods: (A) a rigid probe assembly made from 15 NB PVC pressure pipe and a PVC socket, fixed to a wall with the 15 NB pipe saddles supplied with the switch; (B) strapped to suitable pipework with standard cable ties, using the locating trenches in the KP body; (C) suspended vertically in a pit or tank, with a Kelco KCW cable weight fitted to the cable to hold the switch in place if required; (D) bolted to the side wall of a pit or tank using the 15 NB wall clips provided with the switch. The 15 NB probe assembly protects the cable from mechanical and chemical damage. Avoid violent turbulence and any place where the switch or cable can abrade against adjacent objects.
Magnet — Ferric and Iron Particles
The KP probe switch contains a magnet. Do not use it in applications involving ferric solutions such as ferric chloride, or liquids containing suspended iron particulates: iron sludge may agglomerate around the magnet and prevent the free movement of the float.
Cable Data
S05RN-F 3 × 0.75 mm² cable: black CPE (chlorinated polyethylene) outer sheath, fluorosilicone cable boot, EPR insulation, 3 × 24/0.2 mm plain copper (0.75 mm²), 7.0 ± 0.2 mm diameter, core colours blue (common), black (normally closed) and brown (normally open), voltage rating 300 / 500 V, test voltage 2000 V / 2500 V, minimum bending radius 6 × overall diameter (42 mm), conductor operating temperature -30 °C to +60 °C (85 °C max), CENELEC HD 22.4 S4 & VDE 0282-4/2005, conductor resistance 26.7 Ω/km max per core (20 °C), cable current rating 6 A max (switch ratings apply), maximum suspended length approx. 45 m free-hanging cable. The cable is 10 m only; no other lengths are available. Blue to brown closes and blue to black opens as the liquid level rises.
Serviceability
The KP can be disassembled for cleaning if required. Spare probe assemblies available from Kelco Engineering or your distributor.
