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
    439
    Fri, May 3
    439
    QtyArrives
    439 Fri, May 3
    Questions? Call 1-888-757-4774
  • THERM-X-TROL ST-12 Expansion Tank
    SKU: 141N43
    Brand: Amtrol
    (33)
    $61.45 each
    $235.80 box of 4
    $58.95 each
    398
    Fri, May 3
    398
    QtyArrives
    398 Fri, May 3
    Questions? Call 1-888-757-4774
  • 3/4" Threaded Spring Loaded Check Valve, Lead Free
    SKU: SLCT075
    Brand: Bluefin
    (27)
    $9.15 each
    $91.80 box of 12
    $7.65 each
    674
    Fri, May 3
    674
    QtyArrives
    674 Fri, May 3
    Questions? Call 1-888-757-4774
  • 11" HydroClaw Expansion Tank Support Bracket
    SKU: HC11-A
    Brand: Storm King Enterprises
    (40)
    $40.95 each
    26
    Fri, May 3
    26
    QtyArrives
    26 Fri, May 3
    Questions? Call 1-888-757-4774
  • 1" Threaded Spring Loaded Check Valve Lead Free
    SKU: SLCT100
    Brand: Bluefin
    (27)
    $11.85 each
    $98.50 box of 10
    $9.85 each
    1,564
    Fri, May 3
    1,564
    QtyArrives
    1,564 Fri, May 3
    Questions? Call 1-888-757-4774
  • PLT-5, 2.1 Gallon Potable Water Expansion Tank
    SKU: 0067370
    Brand: Watts
    (4)
    $39.55 each
    187
    Fri, May 3
    187
    QtyArrives
    187 Fri, May 3
    Questions? Call 1-888-757-4774
  • $14.85 each
    $142.50 box of 10
    $14.25 each
    102
    Fri, May 3
    102
    QtyArrives
    102 Fri, May 3
    Questions? Call 1-888-757-4774
  • $17.25 each
    $165.50 box of 10
    $16.55 each
    157
    Fri, May 3
    157
    QtyArrives
    157 Fri, May 3
    Questions? Call 1-888-757-4774
  • 1/2" Threaded Spring Loaded Check Valve, Lead Free
    SKU: SLCT050
    Brand: Bluefin
    (27)
    $6.15 each
    $77.25 box of 15
    $5.15 each
    568
    Fri, May 3
    568
    QtyArrives
    568 Fri, May 3
    Questions? Call 1-888-757-4774
  • 8" HydroClaw Expansion Tank Support Bracket
    SKU: HC8-B
    Brand: Storm King Enterprises
    (24)
    $30.95 each
    Mon, Jun 3 – Mon, Jul 1
    Arrives
    Mon, Jun 3 – Mon, Jul 1
    Questions? Call 1-888-757-4774 or
  • WX-250 (145S1), 44 Gal. WELL-X-TROL Well Tank
    SKU: WX-250
    Brand: Amtrol
    (67)
    $515.95 each
    $990.70 box of 2
    $495.35 each
    149
    Fri, May 3
    149
    QtyArrives
    149 Fri, May 3
    Questions? Call 1-888-757-4774
  • WX-202 (144S29), 20 Gal. WELL-X-TROL Well Tank
    SKU: WX-202
    Brand: Amtrol
    (47)
    $229.95 each
    $441.50 box of 2
    $220.75 each
    100
    Fri, May 3
    100
    QtyArrives
    100 Fri, May 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
    157
    Fri, May 3
    157
    QtyArrives
    157 Fri, May 3
    Questions? Call 1-888-757-4774
  • Pressure Switch, 40/60 PSI, 10 Amp, DPST
    SKU: 9013FSG2J24
    Brand: Square D
    (11)
    $14.75 each
    200
    Fri, May 3
    200
    QtyArrives
    200 Fri, May 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
    200
    Fri, May 3
    200
    QtyArrives
    200 Fri, May 3
    Questions? Call 1-888-757-4774
  • Water Pump Pressure Switch, 30/50 PSI, DPST
    SKU: 9013FSG2J21
    Brand: Square D
    (1)
    $12.25 each
    186
    Fri, May 3
    186
    QtyArrives
    186 Fri, May 3
    Questions? Call 1-888-757-4774
  • $64.95 each
    $167.55 box of 3
    $55.85 each
    Fri, May 10 – Tue, May 14
    Arrives
    Fri, May 10 – Tue, May 14
    Questions? Call 1-888-757-4774 or
  • 1-1/4" MPT Union Brass Tank Tee Package (Lead Free)
    SKU: TFP-2TK132UNL
    Brand: Boshart
    (15)
    $104.95 each
    $270.75 box of 3
    $90.25 each
    Wed, May 8 – Fri, May 10
    Arrives
    Wed, May 8 – Fri, May 10
    Questions? Call 1-888-757-4774 or
  • THERM-X-TROL ST-8 Expansion Tank
    SKU: 140N738
    Brand: Amtrol
    (13)
    $55.55 each
    $213.40 box of 4
    $53.35 each
    73
    Fri, May 3
    73
    QtyArrives
    73 Fri, May 3
    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
    70
    Fri, May 3
    70
    QtyArrives
    70 Fri, May 3
    Questions? Call 1-888-757-4774
  • 1-1/4" Threaded Spring Loaded Check Valve, Lead Free
    SKU: SLCT125
    Brand: Bluefin
    (27)
    $21.25 each
    $142.00 box of 8
    $17.75 each
    107
    Fri, May 3
    107
    QtyArrives
    107 Fri, May 3
    Questions? Call 1-888-757-4774
  • WX-302 (150S1), 86 Gal. WELL-X-TROL Well Tank
    SKU: WX-302
    Brand: Amtrol
    (25)
    $709.95 each
    $1,363.10 box of 2
    $681.55 each
    75
    Wed, May 8 – Fri, May 10
    75
    QtyArrives
    75 Wed, May 8 – Fri, May 10
    Questions? Call 1-888-757-4774
  • $72.95 each
    $280.20 box of 4
    $70.05 each
    69
    Fri, May 3
    69
    QtyArrives
    69 Fri, May 3
    Questions? Call 1-888-757-4774
  • THERM-X-TROL ST-25V Expansion Tank (10.3 Gallon)
    SKU: 143N164
    Brand: Amtrol
    (6)
    $149.95 each
    $431.85 box of 3
    $143.95 each
    188
    Fri, May 3
    188
    QtyArrives
    188 Fri, May 3
    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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