The Therm-X-Trol ST-1 absorbs thermal expansion and pressure surge in tankless and point-of-use water heaters to protect the heat exchanger. Simple to install, the ST-1 features patented air cell technology and requires no precharge adjustment or maintenance. With a 304 stainless steel waterway and a 7-Year limited warranty, the ST-1 delivers big protection in a compact size.

• Shell: High Strength Steel
• Diaphragm: Heavy Duty Butyl NSF/ANSI 61
• Liner: Antimicrobial
• System Connection: Stainless Steel
• Water Circulator: Patented Turbulator®
• Air Valve: Projection Welded
• Air Valve Cap: Patented InSight® Indicator Cap (In-Line Models: ST-5, ST-12)
• Factory Precharge: In-Line Models: 50 PSIG (3.5 bar) Stand Models: 40 PSIG (2.8 bar)