Watts 0066605 Xpansion Tank

The Watts 0066605 ETX-15 is a professional-grade non-potable thermal expansion tank designed for closed-loop hydronic heating systems. Engineered to manage thermal expansion effectively, this unit maintains system pressure safely below the relief valve setting, preventing unnecessary discharge and system stress. The 2.1-gallon carbon steel tank features a rugged butyl diaphragm that separates system water from the pre-charged air cushion, drastically reducing air loss and preventing tank waterlogging. This model is a direct replacement for ET-15 and ETX-15 series tanks and is fully compatible with glycol mixtures, making it a versatile choice for both residential and commercial boiler system maintenance.

With a 1/2" MNPT connection, the 0066605 is designed for easy in-line pipe mounting. It arrives pre-charged to 12 PSI, but includes a standard tire-grade air valve for precise field adjustments tailored to specific static system pressures. Its epoxy-finished shell ensures long-term resistance to corrosion in mechanical rooms. This expansion tank is rated for a maximum temperature of 220°F and a maximum pressure of 75 PSI, providing reliable pressure surge protection in demanding hydronic environments.

• Superior Pressure Management: Effectively absorbs expanded water volume to keep system pressure below the 30-75 PSI relief range.
• Durable Diaphragm Technology: Features a high-grade butyl diaphragm that eliminates the need for frequent air recharging by separating air and water.
• Corrosion Resistant: Built with a carbon steel outer shell and a high-performance epoxy finish for durability in humid mechanical spaces.
• Glycol Compatibility: Certified for use in systems containing antifreeze or glycol-based heat transfer fluids.
• Simplified Installation: Compact 8" x 12.5" dimensions and standard 1/2" NPT threading allow for fast integration into supply piping.

• Can this tank be used for potable house water? No, this is a non-potable expansion tank specifically for closed-loop heating and cooling systems. For domestic water heaters, a potable-rated tank is required.
• How do I check the pre-charge pressure? Using a standard tire pressure gauge on the Schrader valve. Note that system pressure must be zeroed out before taking an accurate air charge reading.
• What is the difference between the ET-15 and ETX-15? The 0066605 ETX-15 is the modern pressurized version designed to replace the older ET-15 series while offering improved diaphragm life and higher pressure ratings.

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.