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Expansion Tanks

  • THERM-X-TROL ST-5 Expansion Tank
    SKU: 140N43
    Brand: Amtrol
    (46)
    $45.95 each
    $176.60 box of 4
    $44.15 each
    277
    Thu, Jun 27
    277
    QtyArrives
    277 Thu, Jun 27
    Questions? Call 1-888-757-4774
  • THERM-X-TROL ST-12 Expansion Tank
    SKU: 141N43
    Brand: Amtrol
    (34)
    $61.45 each
    $235.80 box of 4
    $58.95 each
    241
    Thu, Jun 27
    241
    QtyArrives
    241 Thu, Jun 27
    Questions? Call 1-888-757-4774
  • PLT-5, 2.1 Gallon Potable Water Expansion Tank
    SKU: 0067370
    Brand: Watts
    (6)
    $39.55 each
    439
    Thu, Jun 27
    439
    QtyArrives
    439 Thu, Jun 27
    Questions? Call 1-888-757-4774
  • WX-350 (151S1) 119 Gal. WELL-X-TROL Well Tank
    SKU: WX-350
    Brand: Amtrol
    (17)
    $1,019.95 each
    $1,958.30 box of 2
    $979.15 each
    44
    Mon, Jul 1 – Wed, Jul 3
    44
    QtyArrives
    44 Mon, Jul 1 – Wed, Jul 3
    Questions? Call 1-888-757-4774
  • WX-250 (145S1), 44 Gal. WELL-X-TROL Well Tank
    SKU: WX-250
    Brand: Amtrol
    (68)
    $515.95 each
    $990.70 box of 2
    $495.35 each
    87
    Thu, Jun 27
    87
    QtyArrives
    87 Thu, Jun 27
    Questions? Call 1-888-757-4774
  • WX-302 (150S1), 86 Gal. WELL-X-TROL Well Tank
    SKU: WX-302
    Brand: Amtrol
    (26)
    $709.95 each
    $1,363.10 box of 2
    $681.55 each
    41
    Mon, Jul 1 – Wed, Jul 3
    41
    QtyArrives
    41 Mon, Jul 1 – Wed, Jul 3
    Questions? Call 1-888-757-4774
  • WX-203 (146S30), 32 Gal. WELL-X-TROL Well Tank
    SKU: WX-203
    Brand: Amtrol
    (60)
    $424.95 each
    $815.90 box of 2
    $407.95 each
    132
    Thu, Jun 27
    132
    QtyArrives
    132 Thu, Jun 27
    Questions? Call 1-888-757-4774
  • WX-255 (149S147), 81 Gal. WELL-X-TROL Well Tank
    SKU: WX-255
    Brand: Amtrol
    (27)
    $759.95 each
    $1,459.10 box of 2
    $729.55 each
    50
    Mon, Jul 1 – Wed, Jul 3
    50
    QtyArrives
    50 Mon, Jul 1 – Wed, Jul 3
    Questions? Call 1-888-757-4774
  • WX-202 (144S29), 20 Gal. WELL-X-TROL Well Tank
    SKU: WX-202
    Brand: Amtrol
    (48)
    $229.95 each
    $441.50 box of 2
    $220.75 each
    51
    Thu, Jun 27
    51
    QtyArrives
    51 Thu, Jun 27
    Questions? Call 1-888-757-4774
  • RP-15HP, 20 Gal Residential Pressuriser
    SKU: 2201-39
    Brand: Amtrol
    (9)
    $1,299.95 each
    $2,495.90 box of 2
    $1,247.95 each
    21
    Mon, Jul 1 – Wed, Jul 3
    21
    QtyArrives
    21 Mon, Jul 1 – Wed, Jul 3
    Questions? Call 1-888-757-4774
  • WX-251 (145S10), 62 Gal. WELL-X-TROL Well Tank
    SKU: WX-251
    Brand: Amtrol
    (32)
    $775.95 each
    $1,489.90 box of 2
    $744.95 each
    45
    Mon, Jul 1 – Wed, Jul 3
    45
    QtyArrives
    45 Mon, Jul 1 – Wed, Jul 3
    Questions? Call 1-888-757-4774
  • RP-10HP, 14 Gal Residential Pressuriser
    SKU: 2201-37
    Brand: Amtrol
    (2)
    $1,025.95 each
    $1,969.90 box of 2
    $984.95 each
    14
    Thu, Jun 27
    14
    QtyArrives
    14 Thu, Jun 27
    Questions? Call 1-888-757-4774
  • THERM-X-TROL ST-25V Expansion Tank (10.3 Gallon)
    SKU: 143N164
    Brand: Amtrol
    (7)
    $149.95 each
    $431.85 box of 3
    $143.95 each
    135
    Thu, Jun 27
    135
    QtyArrives
    135 Thu, Jun 27
    Questions? Call 1-888-757-4774
  • WX-202XL (144S240) 26 Gal. WELL-X-TROL Well Tank
    SKU: WX-202XL
    Brand: Amtrol
    (39)
    $279.95 each
    $537.50 box of 2
    $268.75 each
    28
    Thu, Jun 27
    28
    QtyArrives
    28 Thu, Jun 27
    Questions? Call 1-888-757-4774
  • WX-205 (147S44) 34 Gal. WELL-X-TROL
    SKU: WX-205
    Brand: Amtrol
    (18)
    $429.95 each
    $825.50 box of 2
    $412.75 each
    10
    Thu, Jun 27
    10
    QtyArrives
    10 Thu, Jun 27
    Questions? Call 1-888-757-4774
  • RP-25HP, 34 Gal Residential Pressuriser
    SKU: 2201-28
    Brand: Amtrol
    (1)
    $1,779.95 each
    2
    Mon, Jul 1 – Wed, Jul 3
    2
    QtyArrives
    2 Mon, Jul 1 – Wed, Jul 3
    Questions? Call 1-888-757-4774
  • WX-252 (145S20), 86 Gal. WELL-X-TROL Well Tank
    SKU: WX-252
    Brand: Amtrol
    (6)
    $975.95 each
    $1,873.90 box of 2
    $936.95 each
    13
    Mon, Jul 1 – Wed, Jul 3
    13
    QtyArrives
    13 Mon, Jul 1 – Wed, Jul 3
    Questions? Call 1-888-757-4774
  • $529.95 each
    7
    Thu, Jun 27
    7
    QtyArrives
    7 Thu, Jun 27
    Questions? Call 1-888-757-4774
  • $759.95 each
    5
    Mon, Jul 1 – Wed, Jul 3
    5
    QtyArrives
    5 Mon, Jul 1 – Wed, Jul 3
    Questions? Call 1-888-757-4774
  • THERM-X-SPAN T-5 Expansion Tank (2 Gallon)
    SKU: 140735
    Brand: Amtrol
    (12)
    $37.25 each
    $143.00 box of 4
    $35.75 each
    73
    Thu, Jun 27
    73
    QtyArrives
    73 Thu, Jun 27
    Questions? Call 1-888-757-4774
  • $1,024.95 each
    1
    Mon, Jul 1 – Wed, Jul 3
    1
    QtyArrives
    1 Mon, Jul 1 – Wed, Jul 3
    Questions? Call 1-888-757-4774
  • $72.95 each
    $280.20 box of 4
    $70.05 each
    22
    Thu, Jun 27
    22
    QtyArrives
    22 Thu, Jun 27
    Questions? Call 1-888-757-4774
  • THERM-X-TROL ST-8 Expansion Tank
    SKU: 140N738
    Brand: Amtrol
    (13)
    $55.55 each
    $213.40 box of 4
    $53.35 each
    30
    Thu, Jun 27
    30
    QtyArrives
    30 Thu, Jun 27
    Questions? Call 1-888-757-4774
  • $489.95 each
    24
    Thu, Jun 27
    24
    QtyArrives
    24 Thu, Jun 27
    Questions? Call 1-888-757-4774

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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