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Expansion Tanks

  • THERM-X-TROL ST-5 Expansion Tank Product Image
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    THERM-X-TROL ST-5 Expansion Tank 140N43 THERM-X-TROL ST-5 Expansion Tank
    SKU: 140N43
    Brand: Amtrol
    (51)
    $38.99 each
      Box Up & Save 1%  
    $154.36 box of 4
    $38.59 each
    319
    Thu, Dec 26
    319
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    319 Thu, Dec 26
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  • THERM-X-TROL ST-12 Expansion Tank Product Image
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    THERM-X-TROL ST-12 Expansion Tank 141N43 THERM-X-TROL ST-12 Expansion Tank
    SKU: 141N43
    Brand: Amtrol
    (37)
    $61.45 each
      Box Up & Save 4%  
    $235.80 box of 4
    $58.95 each
    218
    Thu, Dec 26
    218
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    218 Thu, Dec 26
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  • PLT-5, 2.1 Gallon Potable<br>Water Expansion Tank Product Image
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    PLT-5, 2.1 Gallon Potable Water Expansion Tank 0067370 PLT-5, 2.1 Gallon Potable Water Expansion Tank
    SKU: 0067370
    Brand: Watts
    (7)
    $42.99 each
    123
    Thu, Dec 26
    123
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    123 Thu, Dec 26
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  • WX-350 (151S1)<br>119 Gal. WELL-X-TROL Well Tank Product Image
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    WX-350 (151S1) 119 Gal. WELL-X-TROL Well Tank WX-350 WX-350 (151S1) 119 Gal. WELL-X-TROL Well Tank
    SKU: WX-350
    Brand: Amtrol
    (17)
    $1,015.99 each
      Box Up & Save 4%  
    $1,958.30 box of 2
    $979.15 each
    74
    Tue, Dec 31 – Fri, Jan 3
    74
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    74 Tue, Dec 31 – Fri, Jan 3
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  • WX-250 (145S1), 44 Gal. WELL-X-TROL Well Tank Product Image
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    WX-250 (145S1), 44 Gal. WELL-X-TROL Well Tank WX-250 WX-250 (145S1), 44 Gal. WELL-X-TROL Well Tank
    SKU: WX-250
    Brand: Amtrol
    (71)
    $479.99 each
      Box Up & Save 4%  
    $919.98 box of 2
    $459.99 each
    69
    Thu, Dec 26
    69
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    69 Thu, Dec 26
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  • WX-302 (150S1), 86 Gal. WELL-X-TROL Well Tank Product Image
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    WX-302 (150S1), 86 Gal. WELL-X-TROL Well Tank WX-302 WX-302 (150S1), 86 Gal. WELL-X-TROL Well Tank
    SKU: WX-302
    Brand: Amtrol
    (28)
    $708.99 each
      Box Up & Save 4%  
    $1,363.10 box of 2
    $681.55 each
    91
    Tue, Dec 31 – Fri, Jan 3
    91
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    91 Tue, Dec 31 – Fri, Jan 3
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  • WX-203 (146S30), 32 Gal. WELL-X-TROL Well Tank Product Image
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    WX-203 (146S30), 32 Gal. WELL-X-TROL Well Tank WX-203 WX-203 (146S30), 32 Gal. WELL-X-TROL Well Tank
    SKU: WX-203
    Brand: Amtrol
    (65)
    $375.99 each
      Box Up & Save 2%  
    $735.38 box of 2
    $367.69 each
    84
    Thu, Dec 26
    84
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    84 Thu, Dec 26
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  • WX-255 (149S147), 81 Gal. WELL-X-TROL Well Tank Product Image
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    WX-255 (149S147), 81 Gal. WELL-X-TROL Well Tank WX-255 WX-255 (149S147), 81 Gal. WELL-X-TROL Well Tank
    SKU: WX-255
    Brand: Amtrol
    (29)
    $699.99 each
      Box Up & Save 4%  
    $1,343.98 box of 2
    $671.99 each
    67
    Tue, Dec 31 – Fri, Jan 3
    67
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    67 Tue, Dec 31 – Fri, Jan 3
    Questions? Call 1-888-757-4774
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  • WX-202 (144S29), 20 Gal. WELL-X-TROL Well Tank Product Image
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    WX-202 (144S29), 20 Gal. WELL-X-TROL Well Tank WX-202 WX-202 (144S29), 20 Gal. WELL-X-TROL Well Tank
    SKU: WX-202
    Brand: Amtrol
    (54)
    $209.99 each
      Box Up & Save 2%  
    $410.78 box of 2
    $205.39 each
    119
    Thu, Dec 26
    119
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    119 Thu, Dec 26
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  • RP-15HP, 20 Gal<br>Residential Pressuriser Product Image
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    RP-15HP, 20 Gal Residential Pressuriser 2201-39 RP-15HP, 20 Gal Residential Pressuriser
    SKU: 2201-39
    Brand: Amtrol
    (9)
    $1,299.95 each
      Box Up & Save 4%  
    $2,495.90 box of 2
    $1,247.95 each
    15
    Tue, Dec 31 – Fri, Jan 3
    15
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    15 Tue, Dec 31 – Fri, Jan 3
    Questions? Call 1-888-757-4774
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  • WX-251 (145S10), 62 Gal. WELL-X-TROL Well Tank Product Image
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    WX-251 (145S10), 62 Gal. WELL-X-TROL Well Tank WX-251 WX-251 (145S10), 62 Gal. WELL-X-TROL Well Tank
    SKU: WX-251
    Brand: Amtrol
    (32)
    $699.99 each
      Box Up & Save 4%  
    $1,345.98 box of 2
    $672.99 each
    15
    Tue, Dec 31 – Fri, Jan 3
    15
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    15 Tue, Dec 31 – Fri, Jan 3
    Questions? Call 1-888-757-4774
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  • RP-10HP, 14 Gal<br>Residential Pressuriser Product Image
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    RP-10HP, 14 Gal Residential Pressuriser 2201-37 RP-10HP, 14 Gal Residential Pressuriser
    SKU: 2201-37
    Brand: Amtrol
    (5)
    $1,025.95 each
      Box Up & Save 2%  
    $2,007.56 box of 2
    $1,003.78 each
    16
    Thu, Dec 26
    16
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    16 Thu, Dec 26
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  • THERM-X-TROL ST-25V Expansion Tank<br>(10.3 Gallon) Product Image
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    THERM-X-TROL ST-25V Expansion Tank (10.3 Gallon) 143N164 THERM-X-TROL ST-25V Expansion Tank (10.3 Gallon)
    SKU: 143N164
    Brand: Amtrol
    (7)
    $139.99 each
      Box Up & Save 4%  
    $404.97 box of 3
    $134.99 each
    86
    Thu, Dec 26
    86
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    86 Thu, Dec 26
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  • WX-202XL (144S240)<br>26 Gal. WELL-X-TROL<br>Well Tank Product Image
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    WX-202XL (144S240) 26 Gal. WELL-X-TROL Well Tank WX-202XL WX-202XL (144S240) 26 Gal. WELL-X-TROL Well Tank
    SKU: WX-202XL
    Brand: Amtrol
    (43)
    $262.99 each
      Box Up & Save 4%  
    $505.98 box of 2
    $252.99 each
    37
    Thu, Dec 26
    37
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    37 Thu, Dec 26
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  • WX-205 (147S44)<br>34 Gal. WELL-X-TROL Product Image
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    WX-205 (147S44) 34 Gal. WELL-X-TROL WX-205 WX-205 (147S44) 34 Gal. WELL-X-TROL
    SKU: WX-205
    Brand: Amtrol
    (20)
    $405.99 each
      Box Up & Save 2%  
    $794.38 box of 2
    $397.19 each
    53
    Thu, Dec 26
    53
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    53 Thu, Dec 26
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  • RP-25HP, 34 Gal<br>Residential Pressuriser Product Image
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    RP-25HP, 34 Gal Residential Pressuriser 2201-28 RP-25HP, 34 Gal Residential Pressuriser
    SKU: 2201-28
    Brand: Amtrol
    (1)
    $1,779.95 each
    6
    Tue, Dec 31 – Fri, Jan 3
    6
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    6 Tue, Dec 31 – Fri, Jan 3
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  • WX-252 (145S20), 86 Gal. WELL-X-TROL Well Tank Product Image
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    WX-252 (145S20), 86 Gal. WELL-X-TROL Well Tank WX-252 WX-252 (145S20), 86 Gal. WELL-X-TROL Well Tank
    SKU: WX-252
    Brand: Amtrol
    (6)
    $949.99 each
      Box Up & Save 4%  
    $1,823.98 box of 2
    $911.99 each
    26
    Tue, Dec 31 – Fri, Jan 3
    26
    QtyArrives
    26 Tue, Dec 31 – Fri, Jan 3
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  • WX-250 (145S1), 44 Gal<br>WELL-X-TROL Well Tank<br>w/ Durabase Stand Product Image
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    WX-250 (145S1), 44 Gal WELL-X-TROL Well Tank w/ Durabase Stand WX-250D WX-250 (145S1), 44 Gal WELL-X-TROL Well Tank w/ Durabase Stand
    SKU: WX-250D
    Brand: Amtrol
    (6)
    $509.99 each
    23
    Thu, Dec 26
    23
    QtyArrives
    23 Thu, Dec 26
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  • WX-255 (149S147), 81 Gal<br>WELL-X-TROL Well Tank<br>w/ Durabase Stand Product Image
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    WX-255 (149S147), 81 Gal WELL-X-TROL Well Tank w/ Durabase Stand WX-255D WX-255 (149S147), 81 Gal WELL-X-TROL Well Tank w/ Durabase Stand
    SKU: WX-255D
    Brand: Amtrol
    (2)
    $759.99 each
    16
    Tue, Dec 31 – Fri, Jan 3
    16
    QtyArrives
    16 Tue, Dec 31 – Fri, Jan 3
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  • THERM-X-SPAN T-5 Expansion Tank<br>(2 Gallon) Product Image
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    THERM-X-SPAN T-5 Expansion Tank (2 Gallon) 140735 THERM-X-SPAN T-5 Expansion Tank (2 Gallon)
    SKU: 140735
    Brand: Amtrol
    (13)
    $31.99 each
      Box Up & Save 4%  
    $122.76 box of 4
    $30.69 each
    326
    Thu, Dec 26
    326
    QtyArrives
    326 Thu, Dec 26
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  • WX1-302 (150S92)<br>86 Gal. WELL-X-TROL<br>Well-X1 Well Tank (Blue) Product Image
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    WX1-302 (150S92) 86 Gal. WELL-X-TROL Well-X1 Well Tank (Blue) WX1-302 WX1-302 (150S92) 86 Gal. WELL-X-TROL Well-X1 Well Tank (Blue)
    SKU: WX1-302
    Brand: Amtrol
    (3)
    $1,024.99 each
    7
    Tue, Dec 31 – Fri, Jan 3
    7
    QtyArrives
    7 Tue, Dec 31 – Fri, Jan 3
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  • WX-101 (140PR1)<br>2 Gal. WELL-X-TROL<br>In-Line Well Tank Product Image
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    WX-101 (140PR1) 2 Gal. WELL-X-TROL In-Line Well Tank WX-101 WX-101 (140PR1) 2 Gal. WELL-X-TROL In-Line Well Tank
    SKU: WX-101
    Brand: Amtrol
    (15)
    $69.99 each
      Box Up & Save 4%  
    $267.96 box of 4
    $66.99 each
    106
    Thu, Dec 26
    106
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    106 Thu, Dec 26
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  • THERM-X-TROL ST-8 Expansion Tank Product Image
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    THERM-X-TROL ST-8 Expansion Tank 140N738 THERM-X-TROL ST-8 Expansion Tank
    SKU: 140N738
    Brand: Amtrol
    (15)
    $49.99 each
      Box Up & Save 4%  
    $191.96 box of 4
    $47.99 each
    131
    Thu, Dec 26
    131
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    131 Thu, Dec 26
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  • WX-203 (146S30), 32 Gal<br>WELL-X-TROL Well Tank<br>w/ Durabase Stand Product Image
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    WX-203 (146S30), 32 Gal WELL-X-TROL Well Tank w/ Durabase Stand WX-203D WX-203 (146S30), 32 Gal WELL-X-TROL Well Tank w/ Durabase Stand
    SKU: WX-203D
    Brand: Amtrol
    (4)
    $399.99 each
    3
    Thu, Dec 26
    3
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    3 Thu, Dec 26
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Resources

Videos

Articles

  • An expansion tank is designed to relieve pressure in both a potable water and closed heating system. An expansion tank ensures a constant pressure is maintained within the pipes so they do not get damaged from excess pressure.

    An expansion tank has two parts which are divided by a rubber diaphragm. The top portion of the tank is connected to the hot water system and is filled with water. The bottom portion is filled with air set at approximately 12 psi. As the hot water system is turned on or off, pressure increases. As pressure increases, the diaphragm in the expansion tank is pushed down. This compresses the air in the tank, creating more space for excess water to enter. This relieves excess pressure in the system and prevents pipes in the system from being damaged.

    In the event that the diaphragm fails, the tank will completely fill with water. If this occurs, the tank must be replaced immediately. To check if the expansion tank is working properly, simply place your hand on the tank and feel its temperature. The top portion of the tank should feel warm to the touch, and the bottom portion of the tank should be room temperature. If the entire tank is warm, it is likely that the tank has completely filled with hot water.

    Expansion tanks have capacities ranging from 2 gallons to several hundred gallons. To determine the size needed for your system, use the Expansion Tank Size Calculator located here.

    We offer a wide selection of
    Therm-X-Trol and Well-X-Trol expansion tanks to suit all of your plumbing and heating needs.

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