Backstop 12-TWH2 Thermal Expansion Tank 2 Gallon

Product Description

The BACKSTOP 12-TWH2 is a 2-gallon thermal expansion tank designed to absorb the increased water volume that results from thermal expansion in closed domestic hot water systems. When a water heater heats cold water, the water expands. In a closed plumbing system, that expanded volume must go somewhere - this tank provides the necessary buffer to protect system pressure. The 2-gallon capacity suits residential water heater installations where local codes require thermal expansion control. Licensed plumbers and mechanical contractors install this tank as a code-compliance component in closed-loop domestic water systems.

The 12-TWH2 is applied in residential and light commercial plumbing systems served by a storage-type water heater. It is particularly relevant where a backflow preventer, pressure-reducing valve, or check valve creates a closed system condition. The tank connects to the cold-water supply line near the water heater and works passively to maintain safe system pressure without requiring electrical power or operator input.

Key Features

• 2-gallon tank capacity sized for residential closed water heater systems
• Passive operation - no electrical connections required
• Designed for closed domestic hot water plumbing systems
• Sold as a single unit

Compatibility

Designed as an OEM-style replacement or new-installation thermal expansion tank for residential closed domestic hot water plumbing systems.

Installation Notes

Installation is performed by a licensed plumber in accordance with the International Plumbing Code (IPC) and applicable local amendments. Shut off the cold-water supply and depressurize the system before connecting the tank. The tank should be installed on the cold-water supply line serving the water heater, upstream of the heater connection. Verify the pre-charge air pressure in the tank matches the system supply pressure before completing the installation.