Watts 0066608 XpansionTank

The Watts 0066608, also identified as the ETX-90, is a high-capacity hydronic expansion tank engineered to manage thermal expansion in closed-loop heating and cooling systems. As the updated version for the legacy ET-90 and ETX-90 models, this unit provides a 15-gallon total tank volume with a 3/4" MNPT connection for seamless integration into supply piping. The carbon steel tank features a rugged butyl diaphragm that physically separates system water from the pre-charged air cushion, effectively preventing waterlogging and minimizing air loss over time. Designed for non-potable applications, it maintains system pressure below the relief valve setting, protecting downstream components like the boiler and circulator pumps from excessive pressure spikes. Compatible with glycol-based systems, this tank supports a maximum operating temperature of 220°F and a maximum working pressure of up to 100 PSI, ensuring stable system pressure in demanding residential and commercial environments.

• Thermal Expansion Control: Effectively absorbs increased water volume during heating cycles to prevent pressure relief valve discharge.
• Durable Construction: Features a welded steel shell with an epoxy finish for long-term resistance to environmental stressors.
• Maintenance Reduction: The high-quality flexible bladder ensures the 12 PSI pre-charge is maintained, reducing the need for frequent manual air adjustments.
• System Compatibility: The 3/4 inch connection and in-line mounting design allow for quick integration into standard hydronic heating headers or air separators.

Is the Watts 0066608 compatible with glycol?
Yes, the ETX-90 is fully compatible with glycol mixtures commonly used in closed-loop hydronic and radiant heating systems.

What is the difference between the ET-90 and the 0066608 ETX-90?
The 0066608 is the modernized replacement for the older ET-90. While the form factor and 15-gallon capacity remain consistent, the ETX-90 offers updated material specifications for improved pressure handling up to 100 PSI.

Can this tank be installed in any orientation?
While vertical installation is standard for maximum air management, the tank is designed for in-line mounting on supply piping. Ensure the piping is properly supported to handle the weight of the tank when at full acceptance volume.

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Disclaimer: While we strive for 100% accuracy, product data and specifications are subject to change. Please contact our team to confirm compatibility or technical details before purchasing.