Pool Link 500 Series, Temperature Sensor

The Pool Link 500 Series Temperature Sensor (Pool Link / Link Automation) is a commercial-grade, solid-state electronic thermistor/RTD sensor probe engineered specifically for the Pool Link 501 and 500 Series automated water chemistry controllers. Plumbed directly into the machined acrylic bypass flow manifold (2-probe, 3-probe, or 4-probe 500 Series chambers) or an inline plumbing tapping saddle, it provides continuous water temperature monitoring to power on-screen temperature tracking, high/low freeze and overheat safety alarms, and automatic temperature-compensated pH/ORP dosing algorithms.

Hardware Architecture & Sensing Elements

Engineered for continuous immersion in aggressive, chemically treated commercial swimming pool, spa, and waterpark recirculation systems:

• High-Accuracy Sensing Element: Encapsulated precision negative temperature coefficient (NTC) thermistor or RTD element matched to the 500/501 Series analog-to-digital processing circuit.

• Corrosion-Resistant Housing: Sensing tip is housed in a chemically inert 316 stainless steel, titanium, or heavy-duty PVDF/polymer thermowell sheath filled with high-efficiency thermally conductive potting epoxy to ensure rapid thermal transfer while isolating internal electronics from line pressure and water penetration.

• Shielded Low-Noise Cable: Heavy-gauge, multi-conductor shielded cable with an internal drain wire and a chemical-resistant PVC/TPE outer jacket that resists degradation from ozone, ambient chloramines, UV radiation, and acid splashes.

• Controller Interface Options: Available with stripped/tinned wire leads for terminal block attachment, or an industrial sealed quick-disconnect connector (such as the CONX round interface) depending on the 500 Series enclosure revision.

• Process Fitting: Threaded 1/2" NPT or 3/4" NPT external body threads (or dedicated compression gland collar) engineered to thread into standard 500 Series probe chamber wells without leaking.

Technical Specifications

• Measurement Range: 32°F to 140°F (0°C to 60°C).

• Measurement Accuracy: $\pm 0.5^\circ\text{F}$ ($\pm 0.3^\circ\text{C}$) throughout typical commercial pool/spa operating ranges (68°F to 104°F).

• Thermal Response Time ($T_{90}$): Stabilizes within 5 to 10 seconds under active bypass flow conditions.

• Cable Length: Standard 10-foot (approx. 3.0 m) lead (with optional 20-foot and 30-foot factory extensions for remote enclosure installations).

• Maximum Working Pressure: 50 PSI (approx. 3.45 bar) within a closed commercial flow cell manifold.

• Operating Ambient Conditions: 32°F to 122°F (0°C to 50°C), up to 95% non-condensing relative humidity.

Installation & Wiring Guide

1. Isolate the Flow Cell: Shut off the inlet and outlet sample bypass valves on the 500 Series probe chamber to relieve internal water pressure.

2. Mount the Sensor: Wrap 2 to 3 layers of PTFE thread tape clockwise around the sensor's male threads. Hand-thread the sensor into the dedicated temperature port of the 500 Series acrylic chamber, then tighten 1 to 1.5 turns with an open-end wrench to seat the seal. Do not overtighten, which can crack the acrylic block.

3. Route the Cable: Run the shielded sensor lead through a dedicated low-voltage conduit or enclosure gland knockout. Keep the cable physically isolated from AC power lines, motor feeds, and dosing pump relay wiring to prevent electrical noise.

4. Terminate to Controller: Land the signal wires on the dedicated TEMP terminal block of the Pool Link 500/501 motherboard (or mate the circular sealed connector if equipped).

5. Pressurize & Inspect: Re-open the bypass valves, restore water flow across the probes, and check the port for any weeping. Confirm on the LCD that the temperature readout stabilizes within expected ranges.