Expansion Tanks

  • 11" HydroClaw Expansion Tank Support Bracket
    SKU: HC11-A
    Brand: Storm King Enterprises
    (37)
    $40.95 each
    131
    Thu, Dec 27
    131
    QtyArrives
    131 Thu, Dec 27
    Questions? Call 1-888-757-4774
  • THERM-X-TROL ST-12 Expansion Tank
    SKU: 141N43
    Brand: Amtrol
    (32)
    $57.65 each
    $219.80 box of 4
    $54.95 each
    Fri, Jan 18 – Fri, Jan 25
    Arrives
    Fri, Jan 18 – Fri, Jan 25
    Questions? Call 1-888-757-4774 or LiveChat Img Live Chat
  • 3/4" Threaded Spring Loaded Check Valve, Lead Free
    SKU: SLCT075
    Brand: Bluefin
    (26)
    $9.15 each
    $91.80 box of 12
    $7.65 each
    1,054
    Thu, Dec 27
    1,054
    QtyArrives
    1,054 Thu, Dec 27
    Questions? Call 1-888-757-4774
  • 1" Threaded Spring Loaded Check Valve Lead Free
    SKU: SLCT100
    Brand: Bluefin
    (26)
    $11.85 each
    $98.50 box of 10
    $9.85 each
    102
    Thu, Dec 27
    102
    QtyArrives
    102 Thu, Dec 27
    Questions? Call 1-888-757-4774
  • $14.85 each
    $142.50 box of 10
    $14.25 each
    128
    Thu, Dec 27
    128
    QtyArrives
    128 Thu, Dec 27
    Questions? Call 1-888-757-4774
  • WX-250 (145S1), 44 Gal. WELL-X-TROL Well Tank
    SKU: WX-250
    Brand: Amtrol
    (65)
    $469.95 each
    $899.90 box of 2
    $449.95 each
    1
    Thu, Dec 27
    1
    QtyArrives
    1 Thu, Dec 27
    Questions? Call 1-888-757-4774
  • $16.75 each
    $159.50 box of 10
    $15.95 each
    70
    Thu, Dec 27
    70
    QtyArrives
    70 Thu, Dec 27
    Questions? Call 1-888-757-4774
  • PLT-5, 2.1 Gallon Potable Water Expansion Tank
    SKU: 0067370
    Brand: Watts
    (4)
    $39.55 each
    111
    Thu, Dec 27
    111
    QtyArrives
    111 Thu, Dec 27
    Questions? Call 1-888-757-4774
  • WX-203 (146S30), 32 Gal. WELL-X-TROL Well Tank
    SKU: WX-203
    Brand: Amtrol
    (60)
    $359.95 each
    $691.90 box of 2
    $345.95 each
    Fri, Jan 18 – Fri, Jan 25
    Arrives
    Fri, Jan 18 – Fri, Jan 25
    Questions? Call 1-888-757-4774 or LiveChat Img Live Chat
  • WX-202 (144S29), 20 Gal. WELL-X-TROL Well Tank
    SKU: WX-202
    Brand: Amtrol
    (46)
    $211.95 each
    $405.90 box of 2
    $202.95 each
    39
    Thu, Dec 27
    39
    QtyArrives
    39 Thu, Dec 27
    Questions? Call 1-888-757-4774
  • 8" HydroClaw Expansion Tank Support Bracket
    SKU: HC8-B
    Brand: Storm King Enterprises
    (23)
    $30.95 each
    82
    Thu, Dec 27
    82
    QtyArrives
    82 Thu, Dec 27
    Questions? Call 1-888-757-4774
  • 1/2" Threaded Spring Loaded Check Valve, Lead Free
    SKU: SLCT050
    Brand: Bluefin
    (26)
    $6.15 each
    $77.25 box of 15
    $5.15 each
    1,489
    Thu, Dec 27
    1,489
    QtyArrives
    1,489 Thu, Dec 27
    Questions? Call 1-888-757-4774
  • THERM-X-SPAN T-5 Expansion Tank (2 Gallon)
    SKU: 140735
    Brand: Amtrol
    (12)
    $35.85 each
    $137.40 box of 4
    $34.35 each
    Fri, Jan 18 – Fri, Jan 25
    Arrives
    Fri, Jan 18 – Fri, Jan 25
    Questions? Call 1-888-757-4774 or LiveChat Img Live Chat
  • Pressure Switch, 40/60 PSI, 10 Amp, DPST
    SKU: 9013FSG2J24
    Brand: Square D
    (8)
    $14.75 each
    55
    Thu, Dec 27
    161
    QtyArrives
    55 Thu, Dec 27
    106 Fri, Dec 28
    Questions? Call 1-888-757-4774
  • WX-202XL (144S240) 26 Gal. WELL-X-TROL Well Tank
    SKU: WX-202XL
    Brand: Amtrol
    (38)
    $255.95 each
    $491.90 box of 2
    $245.95 each
    9
    Thu, Dec 27
    9
    QtyArrives
    9 Thu, Dec 27
    Questions? Call 1-888-757-4774
  • THERM-X-TROL ST-8 Expansion Tank
    SKU: 140N738
    Brand: Amtrol
    (9)
    $51.95 each
    $199.80 box of 4
    $49.95 each
    6
    Thu, Dec 27
    6
    QtyArrives
    6 Thu, Dec 27
    Questions? Call 1-888-757-4774
  • WX-302 (150S1), 86 Gal. WELL-X-TROL Well Tank
    SKU: WX-302
    Brand: Amtrol
    (24)
    $699.95 each
    $1,343.90 box of 2
    $671.95 each
    2
    Wed, Jan 2 – Fri, Jan 4
    2
    QtyArrives
    2 Wed, Jan 2 – Fri, Jan 4
    Questions? Call 1-888-757-4774
  • $65.95 each
    $251.80 box of 4
    $62.95 each
    14
    Thu, Dec 27
    14
    QtyArrives
    14 Thu, Dec 27
    Questions? Call 1-888-757-4774
  • 1-1/4" Threaded Spring Loaded Check Valve, Lead Free
    SKU: SLCT125
    Brand: Bluefin
    (26)
    $21.25 each
    $142.00 box of 8
    $17.75 each
    226
    Thu, Dec 27
    226
    QtyArrives
    226 Thu, Dec 27
    Questions? Call 1-888-757-4774
  • WX-255 (149S147), 81 Gal. WELL-X-TROL Well Tank
    SKU: WX-255
    Brand: Amtrol
    (27)
    $695.95 each
    $1,335.90 box of 2
    $667.95 each
    7
    Wed, Jan 2 – Fri, Jan 4
    7
    QtyArrives
    7 Wed, Jan 2 – Fri, Jan 4
    Questions? Call 1-888-757-4774
  • THERM-X-TROL ST-25V Expansion Tank (10.3 Gallon)
    SKU: 143N164
    Brand: Amtrol
    (6)
    $135.95 each
    $389.85 box of 3
    $129.95 each
    76
    Thu, Dec 27
    76
    QtyArrives
    76 Thu, Dec 27
    Questions? Call 1-888-757-4774
  • Water Pump Pressure Switch, 30/50 PSI, DPST
    SKU: 9013FSG2J21
    Brand: Square D
    (1)
    $12.25 each
    37
    Thu, Dec 27
    119
    QtyArrives
    37 Thu, Dec 27
    82 Fri, Dec 28
    Questions? Call 1-888-757-4774
  • WX-350 (151S1) 119 Gal. WELL-X-TROL Well Tank
    SKU: WX-350
    Brand: Amtrol
    (16)
    $975.95 each
    $1,873.90 box of 2
    $936.95 each
    Wed, Jan 23 – Fri, Feb 1
    Arrives
    Wed, Jan 23 – Fri, Feb 1
    Questions? Call 1-888-757-4774 or LiveChat Img Live Chat
  • WX-251 (145S10), 62 Gal. WELL-X-TROL Well Tank
    SKU: WX-251
    Brand: Amtrol
    (32)
    $639.95 each
    $1,227.90 box of 2
    $613.95 each
    6
    Wed, Jan 2 – Fri, Jan 4
    6
    QtyArrives
    6 Wed, Jan 2 – Fri, Jan 4
    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.
1-888-757-4774 We're here to help
Monday – Thursday
8am–7:45pm ET
Friday
9am–7:45pm ET
  • Product Image

  • Product Image

    Select 2 to 3 items to compare

  • Product Image

    Compare up to 1 more item

Why don't we show the price of this item?

We try to always offer you the lowest prices possible, but some manufacturers require that we only show these low prices once you take further action.

To see the price, simply add the item to your cart or sign in.