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  • #30 Extrol EX-30 Expansion Tank (4.4 Gallon) Product Image
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    #30 Extrol EX-30 Expansion Tank (4.4 Gallon) 102-1 #30 Extrol EX-30 Expansion Tank (4.4 Gallon)
    SKU: 102-1 Amtrol
    SKU: 102-1
    Brand: Amtrol
    (316)
    $40.21 each
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    4,622
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    4,622 Wed, Aug 4
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  • #15 Extrol EX-15 Expansion Tank (2 Gallon) Product Image
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    #15 Extrol EX-15 Expansion Tank (2 Gallon) 101-1 #15 Extrol EX-15 Expansion Tank (2 Gallon)
    SKU: 101-1 Amtrol
    SKU: 101-1
    Brand: Amtrol
    (76)
    $32.54 each
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    1,586
    Wed, Aug 4
    1,586
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    1,586 Wed, Aug 4
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  • #60 Extrol EX-60 Expansion Tank (7.6 Gallon) Product Image
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    #60 Extrol EX-60 Expansion Tank (7.6 Gallon) 103-1 #60 Extrol EX-60 Expansion Tank (7.6 Gallon)
    SKU: 103-1 Amtrol
    SKU: 103-1
    Brand: Amtrol
    (44)
    $74.25 each
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    815
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  • QuickStrap Expansion Tank Mounting Bracket <br>(5 Gal. Capacity) Product Image
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    QuickStrap Expansion Tank Mounting Bracket (5 Gal. Capacity) QS-U QuickStrap Expansion Tank Mounting Bracket (5 Gal. Capacity)
    SKU: QS-U Holdrite
    SKU: QS-U
    Brand: Holdrite
    (6)
    $17.88 each
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    1,139
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    1,139 Wed, Aug 4
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  • 1/2" Pro-Pal Full Port Brass Ball Valve w/ Hi-Flow Hose Drain Product Image
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    1/2" Pro-Pal Full Port Brass Ball Valve w/ Hi-Flow Hose Drain 41672 1/2" Pro-Pal Full Port Brass Ball Valve w/ Hi-Flow Hose Drain
    Contains Lead
    SKU: 41672 Webstone
    SKU: 41672
    Brand: Webstone
    (12)
    $24.53 each
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    539
    Wed, Aug 4
    1,039
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    539 Wed, Aug 4
    500 Thu, Aug 5 – Fri, Aug 6
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  • 11" HydroClaw Expansion Tank Support Bracket Product Image
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    11" HydroClaw Expansion Tank Support Bracket HC11-A 11" HydroClaw Expansion Tank Support Bracket
    SKU: HC11-A Storm King Enterprises
    SKU: HC11-A
    Brand: Storm King Enterprises
    (53)
    $40.95 each
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    357
    Wed, Aug 4
    357
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    357 Wed, Aug 4
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  • ETX-30, Non-Potable Water Expansion Tank<br>(4.5 Gallon) Product Image
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    ETX-30, Non-Potable Water Expansion Tank (4.5 Gallon) 0066606 ETX-30, Non-Potable Water Expansion Tank (4.5 Gallon)
    SKU: 0066606 Watts
    SKU: 0066606
    Brand: Watts
    (18)
    $33.48 each
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    357
    Wed, Aug 4
    357
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    357 Wed, Aug 4
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  • 8" HydroClaw Expansion Tank Support Bracket Product Image
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    8" HydroClaw Expansion Tank Support Bracket HC8-B 8" HydroClaw Expansion Tank Support Bracket
    SKU: HC8-B Storm King Enterprises
    SKU: HC8-B
    Brand: Storm King Enterprises
    (32)
    $30.95 each
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    199
    Wed, Aug 4
    199
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    199 Wed, Aug 4
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  • Nexus Flexconsole - 1/2" x 1/2" NPT - Steel (Red) Product Image
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    Nexus Flexconsole - 1/2" x 1/2" NPT - Steel (Red) F97975 Nexus Flexconsole - 1/2" x 1/2" NPT - Steel (Red)
    Contains Lead
    SKU: F97975 Flamco
    SKU: F97975
    Brand: Flamco
    (10)
    $22.95 each
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    350
    Wed, Aug 4
    350
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    350 Wed, Aug 4
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  • Model 110 Fill-Trol<br>w/ Valve (4.4 Gallon) Product Image
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    Model 110 Fill-Trol w/ Valve (4.4 Gallon) 110-1 Model 110 Fill-Trol w/ Valve (4.4 Gallon)
    SKU: 110-1 Amtrol
    SKU: 110-1
    Brand: Amtrol
    (49)
    $74.50 each
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    268
    Wed, Aug 4
    268
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    268 Wed, Aug 4
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  • SX-30V Extrol Expansion Tank (14 Gallon) Product Image
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    SX-30V Extrol Expansion Tank (14 Gallon) 118-27 SX-30V Extrol Expansion Tank (14 Gallon)
    SKU: 118-27 Amtrol
    SKU: 118-27
    Brand: Amtrol
    (10)
    $134.99 each
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    160
    Wed, Aug 4
    160
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    160 Wed, Aug 4
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  • RX-30 Radiant Extrol Expansion Tank<br>(4.4 Gallon) Product Image
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    RX-30 Radiant Extrol Expansion Tank (4.4 Gallon) 141-305 RX-30 Radiant Extrol Expansion Tank (4.4 Gallon)
    SKU: 141-305 Amtrol
    SKU: 141-305
    Brand: Amtrol
    (13)
    $74.39 each
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    218
    Wed, Aug 4
    218
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    218 Wed, Aug 4
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  • Model 109 Fill-Trol<br>w/ Valve (2 Gallon) Product Image
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    Model 109 Fill-Trol w/ Valve (2 Gallon) 109-1 Model 109 Fill-Trol w/ Valve (2 Gallon)
    SKU: 109-1 Amtrol
    SKU: 109-1
    Brand: Amtrol
    (19)
    $69.60 each
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    153
    Wed, Aug 4
    153
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    153 Wed, Aug 4
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  • SX-40V Extrol Expansion Tank (20 Gallon) Product Image
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    SX-40V Extrol Expansion Tank (20 Gallon) 118-78 SX-40V Extrol Expansion Tank (20 Gallon)
    SKU: 118-78 Amtrol
    SKU: 118-78
    Brand: Amtrol
    (11)
    $154.99 each
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    183
    Wed, Aug 4
    183
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    183 Wed, Aug 4
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  • ETX-60, Non-Potable Water Expansion Tank<br>(6.0 Gallon) Product Image
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    ETX-60, Non-Potable Water Expansion Tank (6.0 Gallon) 0066607 ETX-60, Non-Potable Water Expansion Tank (6.0 Gallon)
    SKU: 0066607 Watts
    SKU: 0066607
    Brand: Watts
    (9)
    $58.79 each
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    118
    Wed, Aug 4
    127
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    118 Wed, Aug 4
    9 Thu, Aug 5
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  • ETX-15, Non-Potable Water Expansion Tank<br>(2.1 Gallon) Product Image
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    ETX-15, Non-Potable Water Expansion Tank (2.1 Gallon) 0066605 ETX-15, Non-Potable Water Expansion Tank (2.1 Gallon)
    SKU: 0066605 Watts
    SKU: 0066605
    Brand: Watts
    (2)
    $29.75 each
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    29
    Wed, Aug 4
    29
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    29 Wed, Aug 4
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  • #90 Extrol EX-90 Expansion Tank (14 Gallon) Product Image
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    #90 Extrol EX-90 Expansion Tank (14 Gallon) 112-1 #90 Extrol EX-90 Expansion Tank (14 Gallon)
    SKU: 112-1 Amtrol
    SKU: 112-1
    Brand: Amtrol
    (15)
    $117.29 each
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    70
    Wed, Aug 4
    70
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    70 Wed, Aug 4
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  • SX-60V Extrol Expansion Tank (32 Gallon) Product Image
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    SX-60V Extrol Expansion Tank (32 Gallon) 118-79 SX-60V Extrol Expansion Tank (32 Gallon)
    SKU: 118-79 Amtrol
    SKU: 118-79
    Brand: Amtrol
    (2)
    $229.98 each
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    57
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    57
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    57 Wed, Aug 4
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  • 1/2" External NPT<br>Heating Expansion<br>Tank (4.4 Gallon) Product Image
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    1/2" External NPT Heating Expansion Tank (4.4 Gallon) TK300-30 1/2" External NPT Heating Expansion Tank (4.4 Gallon)
    SKU: TK300-30 Resideo
    SKU: TK300-30
    Brand: Resideo
    (6)
    $46.94 each
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    91
    Wed, Aug 4
    101
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    91 Wed, Aug 4
    10 Thu, Aug 5
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  • RX-15 Radiant Extrol Expansion Tank (2 Gallon) Product Image
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    RX-15 Radiant Extrol Expansion Tank (2 Gallon) 140-705 RX-15 Radiant Extrol Expansion Tank (2 Gallon)
    SKU: 140-705 Amtrol
    SKU: 140-705
    Brand: Amtrol
    (7)
    $59.66 each
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    98
    Wed, Aug 4
    98
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    98 Wed, Aug 4
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  • 1/2" Pro-Pal Full Port Brass Ball Valve w/ Hi-Flow Hose Drain - FIP x FIP (600 WOG) Product Image
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    1/2" Pro-Pal Full Port Brass Ball Valve w/ Hi-Flow Hose Drain - FIP x FIP (600 WOG) H-44672 1/2" Pro-Pal Full Port Brass Ball Valve w/ Hi-Flow Hose Drain - FIP x FIP (600 WOG)
    SKU: H-44672 Webstone
    SKU: H-44672
    Brand: Webstone
    (1)
    $26.31 each
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    72
    Wed, Aug 4
    451
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    72 Wed, Aug 4
    379 Thu, Aug 5 – Fri, Aug 6
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  • Fill Control Valve Product Image
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    Fill Control Valve 109-15 Fill Control Valve
    SKU: 109-15 Amtrol
    SKU: 109-15
    Brand: Amtrol
    (10)
    $40.00 each
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    65
    Wed, Aug 4
    65
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    65 Wed, Aug 4
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  • RBFF, 1/2" Residential Boiler Fill Fitting Product Image
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    RBFF, 1/2" Residential Boiler Fill Fitting 0386466 RBFF, 1/2" Residential Boiler Fill Fitting
    SKU: 0386466 Watts
    SKU: 0386466
    Brand: Watts
    (4)
    $65.00 each
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    Wed, Aug 18 – Wed, Aug 25
    Arrives
    Wed, Aug 18 – Wed, Aug 25
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  • Model 109 Fill-Trol, <br>Tank Only (2 Gallon) Product Image
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    Model 109 Fill-Trol, Tank Only (2 Gallon) 109-133 Model 109 Fill-Trol, Tank Only (2 Gallon)
    SKU: 109-133 Amtrol
    SKU: 109-133
    Brand: Amtrol
    (15)
    $53.64 each
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    53
    Wed, Aug 4
    53
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    53 Wed, Aug 4
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FAQs, Manuals & Videos

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 Sizing Calculator.

    We offer a wide selection of Amtrol, Watts, and Bell & Gossett expansion tanks to suit all of your plumbing and heating needs.

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