CCEI Stainless Steel Water Level Sensor for RNS-2 Pool Controller – 10 m Cable

Stainless steel level sensor for CCEI RNS-2 control box: precise water level detection

The stainless steel level sensor for RNS-2 is an electronic sensor that detects the presence or absence of water at a specific point in the pool skimmer or balance tank. It connects to the CCEI RNS-2 level control box, which automatically controls a filling solenoid valve to maintain a constant water level in the pool. The sensor comes with a 10-meter cable, allowing it to be installed in the skimmer or balance tank while connecting the RNS-2 box in the technical room. It is made of stainless steel, resistant to corrosion, chlorine, bromine, and salt, for maximum lifespan in a pool environment.

The sensor body measures 2.9 × 1 × 4 cm, and it attaches to a mounting rail with dimensions 3.5 × 1.4 × 5 cm, which can be screwed or glued into the skimmer. This rail mounting allows for precise adjustment of the detection height: you position the sensor at the desired water level, and the RNS-2 regulator automatically maintains this level by opening the solenoid valve as soon as the water drops below the sensor.

Level sensor operation: capacitive detection or contact with water

The CCEI level sensor operates on a principle of contact detection with water or variation in electrical capacitance. When the sensor is immersed in water, it closes an electrical circuit or changes its capacitance, which sends a signal to the RNS-2 box to indicate that the level is correct. When the water level drops and the sensor is exposed to air, the circuit opens or the capacitance changes, and the RNS-2 regulator commands the opening of the filling solenoid valve to restore the level.

This system is extremely reliable because it contains no moving mechanical parts (no float, no spring, no diaphragm). Detection is purely electronic, which eliminates the risk of blockages by limescale, leaves, or debris. The sensor can remain permanently immersed without wear, and its stainless steel casing guarantees total resistance to corrosion, even in highly chlorinated or saltwater.

Why use an RNS-2 automatic level regulator with a sensor?

The water level of a pool naturally fluctuates throughout the season. Evaporation causes the water level to drop several centimeters per week in summer (up to 1 cm per day during hot weather). Splashes and swimmers exiting the pool also remove water from the basin. Conversely, rain raises the level, and backwashes (filter backwashing) remove water from the circuit.

A too low water level causes air intake at the skimmer, which causes the filtration pump to cavitate and can damage it. A too high level reduces the efficiency of surface skimming, as water no longer enters the skimmer correctly. The RNS-2 regulator with a sensor solves this problem by automatically maintaining the optimal level: as soon as the water drops below the sensor, the solenoid valve opens and fills the pool until the water reaches the sensor again. The system then stops automatically, preventing any overflow.

Sensor installation: skimmer or balance tank?

The level sensor can be installed in two main locations depending on the pool configuration:

Installation in the skimmer (classic pools): This is the most common configuration for pools with skimmers. The mounting rail is fixed inside the skimmer, at the desired height for the water level (generally halfway up the skimmer opening, about 10 to 15 cm below the edge of the pool). The 10-meter cable passes through the skimmer's technical duct or a dedicated passage to the technical room where the RNS-2 box is located.

Installation in the balance tank (infinity pools): For infinity pools, the sensor is placed in the balance tank, which collects overflowing water before it is returned to the pool. The RNS-2 regulator then maintains a constant balance tank level, ensuring optimal operation of the overflow cascade. The 10-meter cable connects the sensor in the tank to the RNS-2 box located in the technical room.

During installation, it is important to position the sensor away from eddies and turbulence, in an area where the water is relatively calm. Avoid placing it directly in front of the return water inlet or in the skimmer outlet flow, as waves could trigger untimely opening/closing of the solenoid valve.

10-meter cable: sufficient distance between sensor and RNS-2 box

The 10-meter electrical cable supplied with the sensor covers the typical distance between the skimmer (or balance tank) and the technical room in most residential installations. For large pools or installations where the technical room is very far away, the cable can be extended with a waterproof electrical cable of the same cross-section (generally 2 × 0.75 mm²). Extensions must be made with IP68 waterproof connectors or waterproof junction boxes, and the cable must be mechanically protected in a buried TPC or PVC conduit.

The cable is pre-installed and soldered to the sensor, ensuring perfect sealing at the connection point. Therefore, it is not necessary to make a waterproof connection on the sensor side; only the connection to the RNS-2 box needs to be made (connection via screw terminal block in the box).

Stainless steel material: maximum resistance to chlorine, bromine, and salt

The sensor is made of stainless steel (likely 316L or 304 stainless steel), the reference material for equipment in permanent contact with pool water. Stainless steel perfectly resists chlorine, bromine, salt (salt electrolysis), UV, and temperature variations (from 0 to 40 °C in an outdoor pool). It does not corrode, rust, and retains its mechanical and electrical properties for decades.

The choice of stainless steel is particularly important for saltwater pools with electrolyzers, where plastic or ordinary ferrous metal sensors would corrode quickly. 316L stainless steel, if used, contains molybdenum, which further enhances corrosion resistance in saline environments. CCEI stainless steel sensors are designed to last as long as the pool itself, without requiring preventive replacement.

Exclusive compatibility with the CCEI RNS-2 box

This sensor is specifically designed for the CCEI RNS-2 level control box. It cannot be used with other brands or models of level regulators, as the detection protocol and electrical characteristics (voltage, resistance, capacitance) are specific to the RNS-2. Likewise, sensors from other manufacturers are generally not compatible with the RNS-2, unless they meet the exact same electrical specifications.

The RNS-2 box is an autonomous electronic regulator that controls a 230V solenoid valve for automatic pool filling. It has settings for the maximum filling time (overflow safety in case of sensor failure), and it can be connected to a centralized pool management system. The RNS-2 box and the sensor form a complete system for automating the water level.

When to replace the level sensor? Signs of failure

CCEI stainless steel level sensors are extremely reliable and have a lifespan of 10 to 15 years or more in normal use. However, several signs may indicate that a sensor is failing and needs to be replaced:

Continuous filling or no filling: If the solenoid valve remains continuously open (overflow) or never opens (too low level), first check the cable and connections to the RNS-2 box. If the wiring is correct, the sensor is probably short-circuited (continuous filling) or open-circuited (no filling).

Erratic or intermittent detections: If the regulator repeatedly and quickly opens and closes the solenoid valve, this may indicate a dirty sensor (limescale or biofilm deposit) or oxidation of internal electrical contacts. Clean the sensor with white vinegar or diluted hydrochloric acid. If the problem persists, replace the sensor.

No reaction to level change: If you manually empty the pool and the regulator does not command filling even though the water is well below the sensor, check the electrical continuity of the cable with a multimeter. A cut cable or an oxidized connector prevents the signal from reaching the box.

Before replacing the sensor, always test the complete system: check that the RNS-2 box is powered, that the solenoid valve is working (test it in manual mode if the box allows it), and that the electrical connections are clean and tight. In many cases, a simple cleaning of the sensor or tightening of connections is enough to restore operation.

Minimal maintenance: annual sensor cleaning

The level sensor requires virtually no maintenance. Annual cleaning is recommended, preferably at the beginning of the season, to remove limescale, algae, or biofilm deposits that could disrupt detection. Remove the sensor from its mounting rail, rub it with a soft sponge and white vinegar (to dissolve limescale), rinse with clean water, then reposition it in the skimmer or balance tank. Take advantage of this cleaning to check the condition of the cable and connections to the RNS-2 box.

If your water is very hard (TH > 25 °F), semi-annual descaling may be necessary. In saltwater pools with an electrolyzer, also check that limescale deposits do not form on the sensor due to too intense chlorine production or too high pH (which promotes the precipitation of calcium carbonate).

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