Expansion Tanks
Lead Content Warning
Do not use this item for any installation or repair of potable water applications. This product does not comply with the "Safe Drinking Water Act," which requires that products meet low-lead standards in order to be used in systems providing water for human consumption (drinking or cooking). This item is for non-potable (non-human consumption) water applications only.
Lead Content Warning
This product does not comply with the Safe Drinking Water Act, which requires that products used in any system providing water for human consumption (drinking or cooking) to meet low-lead standards. Please check the box below to confirm you are aware that this item is for non-potable water applications only.
You must agree to this statement in order to purchase this product.
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THERM-X-TROL ST-5 Expansion TankSKU: 140N43Brand: Amtrol
(46)439Fri, May 3439Qty Arrives 439 Fri, May 3 Questions? Call 1-888-757-4774 -
THERM-X-TROL ST-12 Expansion TankSKU: 141N43Brand: Amtrol(33)398Fri, May 3398Qty Arrives 398 Fri, May 3 Questions? Call 1-888-757-4774 -
3/4" Threaded Spring Loaded Check Valve, Lead FreeSKU: SLCT075Brand: Bluefin(27)674Fri, May 3674Qty Arrives 674 Fri, May 3 Questions? Call 1-888-757-4774 -
11" HydroClaw Expansion Tank Support BracketSKU: HC11-ABrand: Storm King Enterprises(40)26Fri, May 326Qty Arrives 26 Fri, May 3 Questions? Call 1-888-757-4774 -
1" Threaded Spring Loaded Check Valve Lead FreeSKU: SLCT100Brand: Bluefin(27)1,564Fri, May 31,564Qty Arrives 1,564 Fri, May 3 Questions? Call 1-888-757-4774 -
PLT-5, 2.1 Gallon Potable Water Expansion TankSKU: 0067370Brand: Watts(4)187Fri, May 3187Qty Arrives 187 Fri, May 3 Questions? Call 1-888-757-4774 -
QuickStrap Expansion Tank Mounting Bracket (2.5 Gal. Capacity)SKU: QS-5Brand: Holdrite(26)102Fri, May 3102Qty Arrives 102 Fri, May 3 Questions? Call 1-888-757-4774 -
QuickStrap Expansion Tank Mounting Bracket (5 Gal. Capacity)SKU: QS-12Brand: Holdrite(27)157Fri, May 3157Qty Arrives 157 Fri, May 3 Questions? Call 1-888-757-4774 -
1/2" Threaded Spring Loaded Check Valve, Lead FreeSKU: SLCT050Brand: Bluefin(27)568Fri, May 3568Qty Arrives 568 Fri, May 3 Questions? Call 1-888-757-4774 -
8" HydroClaw Expansion Tank Support BracketSKU: HC8-BBrand: Storm King Enterprises(24) -
WX-250 (145S1), 44 Gal. WELL-X-TROL Well TankSKU: WX-250Brand: Amtrol(67)149Fri, May 3149Qty Arrives 149 Fri, May 3 Questions? Call 1-888-757-4774 -
WX-202 (144S29), 20 Gal. WELL-X-TROL Well TankSKU: WX-202Brand: Amtrol(47)100Fri, May 3100Qty Arrives 100 Fri, May 3 Questions? Call 1-888-757-4774 -
WX-203 (146S30), 32 Gal. WELL-X-TROL Well TankSKU: WX-203Brand: Amtrol(60)157Fri, May 3157Qty Arrives 157 Fri, May 3 Questions? Call 1-888-757-4774 -
Pressure Switch, 40/60 PSI, 10 Amp, DPSTSKU: 9013FSG2J24Brand: Square D(11)200Fri, May 3200Qty Arrives 200 Fri, May 3 Questions? Call 1-888-757-4774 -
THERM-X-SPAN T-5 Expansion Tank (2 Gallon)SKU: 140735Brand: Amtrol(12)200Fri, May 3200Qty Arrives 200 Fri, May 3 Questions? Call 1-888-757-4774 -
Water Pump Pressure Switch, 30/50 PSI, DPSTSKU: 9013FSG2J21Brand: Square D(1)186Fri, May 3186Qty Arrives 186 Fri, May 3 Questions? Call 1-888-757-4774 -
1" MPT Solid Brass Tank Tee Package, 40-60 Pressure Switch (Lead Free)SKU: TFP-2TK252J24NLBrand: Boshart(13) -
1-1/4" MPT Union Brass Tank Tee Package (Lead Free)SKU: TFP-2TK132UNLBrand: Boshart(15) -
THERM-X-TROL ST-8 Expansion TankSKU: 140N738Brand: Amtrol(13)73Fri, May 373Qty Arrives 73 Fri, May 3 Questions? Call 1-888-757-4774 -
WX-202XL (144S240) 26 Gal. WELL-X-TROL Well TankSKU: WX-202XLBrand: Amtrol(39)70Fri, May 370Qty Arrives 70 Fri, May 3 Questions? Call 1-888-757-4774 -
1-1/4" Threaded Spring Loaded Check Valve, Lead FreeSKU: SLCT125Brand: Bluefin(27)107Fri, May 3107Qty Arrives 107 Fri, May 3 Questions? Call 1-888-757-4774 -
WX-302 (150S1), 86 Gal. WELL-X-TROL Well TankSKU: WX-302Brand: Amtrol(25)75Wed, May 8 – Fri, May 1075Qty Arrives 75 Wed, May 8 – Fri, May 10 Questions? Call 1-888-757-4774 -
WX-101 (140PR1) 2 Gal. WELL-X-TROL In-Line Well TankSKU: WX-101Brand: Amtrol(14)69Fri, May 369Qty Arrives 69 Fri, May 3 Questions? Call 1-888-757-4774 -
THERM-X-TROL ST-25V Expansion Tank (10.3 Gallon)SKU: 143N164Brand: Amtrol(6)188Fri, May 3188Qty Arrives 188 Fri, May 3 Questions? Call 1-888-757-4774 -
WX-255 (149S147), 81 Gal. WELL-X-TROL Well TankSKU: WX-255Brand: Amtrol(27)70Wed, May 8 – Fri, May 1070Qty Arrives 70 Wed, May 8 – Fri, May 10 Questions? Call 1-888-757-4774 -
WX-350 (151S1) 119 Gal. WELL-X-TROL Well TankSKU: WX-350Brand: Amtrol(17)78Wed, May 8 – Fri, May 1078Qty Arrives 78 Wed, May 8 – Fri, May 10 Questions? Call 1-888-757-4774 -
DuraBase Tank Spacer for 22" & 26" Steel StandSKU: DURABASE-22Brand: Amtrol(7)51Fri, May 351Qty Arrives 51 Fri, May 3 Questions? Call 1-888-757-4774 -
THERM-X-SPAN T-12 Expansion Tank (4.4 Gallon)SKU: 141363Brand: Amtrol(3)129Fri, May 3129Qty Arrives 129 Fri, May 3 Questions? Call 1-888-757-4774 -
WX-251 (145S10), 62 Gal. WELL-X-TROL Well TankSKU: WX-251Brand: Amtrol(32)51Wed, May 8 – Fri, May 1051Qty Arrives 51 Wed, May 8 – Fri, May 10 Questions? Call 1-888-757-4774 -
WX-102 (141PR1) 4.4 Gal. WELL-X-TROL In-Line Well TankSKU: WX-102Brand: Amtrol(13)40Fri, May 340Qty Arrives 40 Fri, May 3 Questions? Call 1-888-757-4774
Resources
Articles
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More About Expansion Tanks
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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