Amtrol 140N43 Therm-X-Trol ST-5 Thermal Expansion Tank

The 140N43 from Amtrol is a Therm-X-Trol ST-5 Thermal Expansion Tank. It's designed for use in domestic hot water heating systems to eliminate the potential hazards of water expansion.
Water heater expansion tank is commonly installed in a domestic hot water system that contains a backflow preventer, a check valve or a pressure reducing valve.


  • Eliminates the waste of energy and water, thus saving money;
  • Protects the water heater and plumbing fixtures from premauture failure;
  • Reduces potential safety hazards associated with thermal expansion;
  • Prevents a dangerous pressure build-up in the system;
  • Prevents the relief valve from going off;
  • Therm-X-Trol brand is the #1 choice of Professional Installers;

Standards & Approvals:

  • NSF/ANSI 61®, IAPMO, SBCCI & City of Los Angeles listings.

Amtrol ST-5 Applications:

  • Residentail water heaters, laundromats, dormitories, office/apartment buildings, restaurants, etc.

Technical Specifications:

  • Factory pre-charged 40 psig;
  • System connection: 3/4" male threaded;
  • Stainless steel system connection;
  • Max. operating temperature: 200F;
  • Max. operating pressure: 150 psi;
  • Expansion tank volume: 2.0 gallons;
  • Max. acceptance factor: 0.45;
  • Height: 12-5/8";
  • Diameter: 8";
  • Shipping weight: 5 lbs.


  • 5-year manufacturer's warranty. 
2 Gallons
Product Type
Expansion Tank

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Amtrol 140N43 Therm-X-Trol ST-5 Thermal Expansion Tank

  • Views: 4179
  • Amtrol 140N43 Therm-X-Trol ST-5 Thermal Expansion Tank QR Code
  • Brand: Amtrol
  • Model: 140N43
  • MPN: 140N43
  • Availability: 1
  • $ 56.95

Tags: Expansion Tanks, Heating Supply, Plumbing Supply, PEX, Pipe Fittings, Residential Plumbing