Sensing Solutions for Pool & Spa Heat Pumps
Temperature Sensors & Probe Assemblies — Sensing Technologies
Pool and spa heat pumps operate continuously in a demanding environment: exposure to chlorinated or saline water, outdoor UV and weather, freeze/thaw cycles, and tight efficiency targets that demand precise temperature measurement at every point in the refrigerant and water circuit. A sensor that drifts or fails can mean wasted energy, nuisance shutdowns, or equipment damage.
Sensing Technologies has supplied temperature sensors to pool and spa heat pump OEMs and system integrators for decades. A critical component supplier to the industry leaders, we understand the specific demands of residential and commercial pool heating — from the freeze protection sensor mounted in the water manifold to the refrigerant suction-line thermistor inside the compressor cabinet. Every assembly we build for this market is designed and tested to hold up in your exact operating environment.
As a division of MCS — manufacturers of the Magnum and NitroMag control systems widely used in commercial Refrigeration and HVAC/R applications — we can supply sensors that are pre-matched to your specific control platforms, eliminating calibration uncertainty between your sensing and control systems. Our capabilities also include customized PCB board and custom control panel design, manufacturing, and support for your ongoing controls upgrade needs.
Where Our Sensors Are Used
Measures pool return water temperature entering the heat exchanger.
NTC ThermistorConfirms heat transfer efficiency; protects against overtemperature.
NTC ThermistorSuction and discharge line sensing for compressor protection and defrost logic.
NTC / RTDOutside air temperature for efficiency optimization and freeze protection activation.
NTC ThermistorPool & Spa Application Areas
Inlet and outlet water temperature sensing, ambient air sensing for efficiency control. Compact probe assemblies with NPT or compression fittings for standard plumbing integration.
Higher water temperature ranges (up to 104°F / 40°C set point) with tight accuracy requirements. Thermistors with ±0.1°C interchangeable accuracy ensure consistent comfort control.
High-duty systems for hotels, fitness centers, and aquatic facilities often paired with MCS Magnum controllers. Sensors pre-matched to MCS platforms available for seamless integration.
Direct-immersion sensors for water manifolds and above-ground plumbing. Designed for outdoor installation with UV-resistant materials and sealed terminations to prevent moisture intrusion.
Air-source heat pumps operating below 50°F require reliable coil and ambient temperature sensing to trigger defrost cycles without unnecessary interruption to pool heating.
Differential temperature control between solar collector and pool water requires two matched sensors. Sensing Technologies can supply matched pairs to minimize measurement offset.
Sensor Selection Guide
| Sensing Point | Typical Range | Sensor Type | Resistance | Notes |
|---|---|---|---|---|
| Pool Water Inlet | 40–95°F (4–35°C) | NTC | 10 kΩ (Mat. Z or C) | Immersion probe; chlorine-resistant housing |
| Pool Water Outlet | 60–105°F (15–40°C) | NTC | 10 kΩ (Mat. Z or C) | High-temp spa up to 40°C set point |
| Ambient Air Temp. | –4–120°F (–20–49°C) | NTC | 10 kΩ or 50 kΩ (Mat. Z/D) | Shielded outdoor housing; UV-resistant wire |
| Freeze Protection | –10–40°F (–23–4°C) | NTC | 10 kΩ or 30 kΩ (Mat. Z/D) | Fast thermal response; weatherproof enclosure |
| Refrigerant Suction Line | 20–70°F (–7–21°C) | NTC | 10 kΩ (Mat. Z) | Clamp-on or strap-on assembly; insulated lead |
| Compressor Discharge | 100–250°F (38–121°C) | NTC / RTD | 10 kΩ NTC or Pt100 RTD | High-temp rating; stainless steel thermowell recommended |
| Heat Exchanger Surface | 40–160°F (4–71°C) | NTC | 10 kΩ (Mat. Z or C) | Surface-mount flat-pack or adhesive probe style |
| Solar Collector (Hybrid) | 50–200°F (10–93°C) | NTC / RTD | 10 kΩ or Pt100 RTD | High solar exposure; matched pairs for differential control |
All NTC thermistors available with epoxy-coated chip construction. Custom probe termination (NPT, compression, clamp-on, surface-mount) engineered to your requirements. RTD elements conform to DIN EN 60751.
Why Choose Sensing Technologies
USA Manufacturing
Every probe assembly is designed, assembled, and tested in Fort Myers, Florida. No offshore outsourcing — full quality traceability from raw elements to finished assembly.
Fast Thermal Response
Thermally conductive epoxy coatings and small-mass probe designs minimize thermal lag — critical for accurate freeze protection triggering and efficiency control.
Custom Labeling & Wire Colors
Advanced equipment provides custom labeling options to assist with branding, placement and replacement needs, and quality control tracking.
Chemical Resistance
Housings and over molds selected for long-term resistance to chlorinated and saline pool water, preventing sensor degradation and drift over years of continuous immersion.
Custom Enclosures & Terminations
NPT-threaded immersion housings, compression fittings, clamp-on styles, and surface-mount pads — engineered to your plumbing and panel interface requirements.
30+ Years of Experience
Sensing Technologies has been supplying pool and spa OEMs since the early 1990s. We know what fails in this environment — and how to design it out from the start.
Our Custom Design Process
Application Review
Tell us your temperature range, accuracy requirement, installation method, connectivity type, and the environment your sensor will face. We'll identify the right sensing element and construction approach from the first conversation.
Design & Engineering
Our engineers develop probe assembly design, selecting housing materials, sealing methods, wire gauge and insulation, and termination style — all optimized for your operating environment and installation constraints.
Prototype & Validation
Sample assemblies are built and tested for accuracy, thermal response, and environmental integrity before production begins. We encourage customers to test prototypes in their actual application.
Production & Quality Testing
Every production assembly is tested before shipping. Resistance and accuracy are verified against the specified tolerance. Full documentation is available for OEM qualification requirements.