THERM-X-TROL ST-8 Expansion Tank Zoom

THERM-X-TROL ST-8 Expansion Tank


Brand: Amtrol

Qty Price
/ each
$223.80 / box (4 units x $55.95)
In Stock! Ships in 24-48 Hours
(17 Available)



Tank Volume: 3.2 Gallons
Max Accept. Factor: 0.59
Diameter (Inches): 9"
Height: 15"
Weight (lbs): 7 lbs
Warranty: 5-Year Limited Warranty
Size: 3/4"
Material: Steel
Application: Plumbing
Max Pressure (PSI): 150
Temperature Range (F): 200°F MAX

Description for Amtrol 140N738

Amtrol ST-8 (Therm-X-Trol) is a water heater expansion tank, 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.

Amtrol ST-8 Advantages:

  • 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

THERM-X-TROL ST-8 Expansion Tank


by PowerReviews
AmtrolTHERM-X-TROL ST-8 Expansion Tank

(based on 1 review)

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Reviewed by 1 customer

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Easy Installation and Peace of Mind

By atrain68

from Atlanta, GA

Verified Reviewer



      Best Uses

        Comments about THERM-X-TROL ST-8 Expansion Tank:

        Add some teflon tape and screw in the cylinder. We have high city water pressure coming in at nearly 100-110 psi. We keep our water pressure reducing valve set around 50-55 psi and keep our water temp between 130 and 140 degrees.

        DYI advice. I would not assume the cylinder is precharged to the right pressure. Before installation, be sure you get a bicycle pump to pressurize the expansion tank so that it is equal to your incoming water pressure. You can measure your water pressure with a $10 gauge from a big box store.

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        1 Question | 1 Answer
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        • THERM-X-TROL ST-8 Expansion Tank


          instructions state to install vertically. Does it matter if water connection is top or bottom? the figure shows water on top. Does it matter?
          Asked on 1/20/2015 by Tom from MD

          1 answer

          • CUSTOMER CARE


            no it shouldnt

            Answered on 1/21/2015 by Supplyhouse Staff from New York
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