Pool heat exchangers

Pool heat exchangers operate by transferring thermal energy between two independent hydraulic circuits without mixing their fluids.

The system consists of two clearly distinct paths:

• Primary circuit: carries high-temperature water pumped from the home boiler, heat pump, or solar panels.
• Secondary circuit: carries pool water pumped by the filtration pump after it passes through the sand filter.

Counterflow heat exchange occurs through the walls of a tube bundle or internal plates. This mechanism maximizes performance and raises the pool’s temperature by using the heating capacity in kW of your existing home installation.

If your pool uses salt electrolysis, you must choose a heat exchanger made with pure titanium plates or tubes.

Water with high salt concentrations tends to aggressively corrode ordinary stainless steel, including AISI 316 alloys, causing pitting from galvanic corrosion within just a few months of continuous use. Titanium is immune to attack by sodium chloride and aggressive chemical treatments. Our catalog includes advanced technical solutions such as the Zodiac Heat Line 20 Without recirculation pump, designed with highly corrosion-resistant components to extend the unit’s service life.

The main difference is that the unit’s own chassis includes the circulation, safety, and control components.

A basic or bare heat exchanger includes only the heat exchange body. You need to install the circulation pump for the primary circuit, the check valve, and the external electronic controller separately. By contrast, a complete preassembled unit includes a secondary circulator, a digital control thermostat, and a safety flow switch. This integrated design greatly simplifies connections in the technical room, ensures stable heat exchange flow rates, and reduces the labor hours required for installation.

To select the heating capacity, estimate an average of 1 kW per cubic meter of water if you want to heat the pool in 24 to 48 hours.

A standard 40 m³ outdoor pool requires a 40 kW heat exchanger operating with boiler water at 80 °C in the primary circuit. If the boiler supplies lower-temperature water, as with condensing circuits at 60 °C or air-source heat pumps at 45 °C, the unit’s nominal output decreases by 30% to 50%. In these circumstances, you must oversize the heat exchanger’s capacity to compensate for the smaller temperature difference and ensure effective heating of the pool.

Pool heat exchangers are always installed in the return pipe to the pool, just after filtration and before any chemical treatment system.

The correct order of installation in the equipment room is:

• Water intake: take water from the sand or glass filter outlet to prevent solid particles from blocking the internal pipes.
• Bypass installation: connect using three PVC valves to regulate the flow without restricting the main flow and minimize pressure loss.
• Downstream dosing: always position the salt chlorinator or chemical doser downstream so concentrated water does not come into contact with the metal tubes.

This setup prevents mechanical failures and optimizes even temperature distribution.

We recommend buying a complete unit factory-equipped with a circulation pump, control panel, and built-in safety features.

An integrated system reduces the risk of incompatibility between the pump and the heating unit. Preassembled models such as the Zodiac Heat Line Plus 20 with circulation pump. incorporate a flow switch, circulator, and digital thermostat in a single technical unit. This optimizes auxiliary electricity consumption, automatically stops heating if the main filtration system is switched off, and simplifies the external plumbing in the equipment room.

Yes, a heat exchanger is fully compatible with an air-source heat pump, provided you choose a multi-tube model or a plate model with high thermal efficiency.

Air-source heat pumps deliver water to the primary circuit at temperatures between 35 °C and 50 °C, considerably lower than the 80 °C supplied by a fossil-fuel boiler. Because the temperature difference between the incoming water and the pool is smaller, the heat transfer area must be significantly larger. To compensate for this difference in temperature gradient, a heat exchanger is selected with a theoretical nominal output two or three times greater than the pool volume, ensuring fast, consistent heating throughout the season.