Hurlcon Astralpool HX 120 Gas Heater Heat Exchanger - HX120 also WX series

Astralpool Hurlcon HX 120 heat exchanger (tube bundle) replacement for all Hurlcon and Astralpool HX, WX, and WWDG series heaters. Also known as the tube bundle, or heater coils. Tubes are made of cupro-nickel.  

Where replacing a heat exchanger due to a leak, we strongly recommend replacing the Manifold & Seals.

Important Information on Heat Exchangers for Pool & Spa Gas Heaters

The CuproNickel and Copper components used in these heat exchangers have remained consistent for nearly 30 years. This is a time-tested, proven design known for its durability and thermal efficiency in pool and spa heating systems. We regularly see heaters with these heat exchangers last over 20 years when cared for.

How They Work - Pool and spa gas heater heat exchangers transfer heat from the combustion chamber to the water that circulates through the unit. Materials like Copper and CuproNickel are used due to their excellent thermal conductivity, helping the system heat water quickly and efficiently.

Common Cause of Failure: Chemical Corrosion. The most frequent cause of failure in these heat exchangers is chemical corrosion, not mechanical or manufacturing faults.

Signs of Corrosion Damage:

• Tiny pinholes forming in the tubing or fittings (particularly on elbows)
• Blue or green discoloration in the water
• High copper levels detected in water tests

These symptoms mean the heat exchanger has been chemically attacked.

Why Spa and Pool Heaters Are Especially Vulnerable
Pool and spa heaters operate under high temperature conditions, which can amplify the effects of poor water chemistry.

Spa water, in particular, is often treated with high levels of sanitizer and kept at elevated temperatures, increasing corrosive risk.

Low pH (acidic water) and the use of bromine tablets are especially harsh on heat exchangers.

Even a brief imbalance in water chemistry can lead to permanent damage.

Pro Tips: Test and balance your pool or spa water weekly to protect your investment. 

Maintain: 

• pH between 7.2 – 7.8
• Total alkalinity between 80 – 160 ppm
• Calcium Hardness: 150-400ppm
• Avoid use of Bromine tablets if possible
• Never use Chlorine tablets

Warranty: These heat exchangers include a 1-year limited warranty. However, damage caused by chemical corrosion is not covered under warranty, as it is a result of water chemistry mismanagement rather than a product defect.

Learn More: 
For detailed guidance on identifying and preventing chemical corrosion, click: Corrosive Water Damage 

Weight When New: 4.5-4.6kg - If heat exchanger weighs less than the above, the copper has been eroded away. If it weighs more, it may be full of calcium.