Amtrol ST-12 Thermal Expansion Tank

The Amtrol ST-12 Thermal Expansion Tank is designed for closed potable water systems and delivers reliable protection against pressure fluctuations in an efficient in-line format. This tank combines a heavy-duty butyl diaphragm with an antimicrobial inner lining, ensuring durable performance and cleaner water over time.

With 3/4 inch female threaded inlet/outlet connections, a 4.4 gallon capacity, and factory pre-charged air, the ST-12 supports steady operation under demanding conditions. The urethane top-coated steel shell adds ruggedness, while the stainless steel system connection and turbulator water circulator help maintain system efficiency.

• Heavy-duty butyl diaphragm for long life
• Factory pre-charged air at 50 PSIG
• Urethane top-coated steel tank with antimicrobial inner lining
• 3/4" female threaded inlet/outlet connections
• 4.4 gallon capacity; compact 11" diameter x 15" height
• Pressure rating 150 PSIG and temperature rating 200°F
• Projection welded air valve, turbulator water circulator, and stainless steel system connection
• Lead-free construction; NSF/ANSI 61, IAPMO R and T, ISO 9001 compliant
• Warranty: 5 years