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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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Add to ListAdd to ListTHERM-X-TROL ST-5 Expansion Tank 140N43 THERM-X-TROL ST-5 Expansion TankSKU: 140N43Brand: Amtrol
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Add to ListAdd to ListWX-350 (151S1) 119 Gal. WELL-X-TROL Well Tank WX-350 WX-350 (151S1) 119 Gal. WELL-X-TROL Well TankSKU: WX-350Brand: Amtrol(17)74Tue, Dec 31 – Fri, Jan 3Add to List -
![WX-250 (145S1), 44 Gal. WELL-X-TROL Well Tank Product Image]()
Add to ListAdd to ListWX-250 (145S1), 44 Gal. WELL-X-TROL Well Tank WX-250 WX-250 (145S1), 44 Gal. WELL-X-TROL Well TankSKU: WX-250Brand: Amtrol(71)Add to List -
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Add to ListAdd to ListWX-302 (150S1), 86 Gal. WELL-X-TROL Well Tank WX-302 WX-302 (150S1), 86 Gal. WELL-X-TROL Well TankSKU: WX-302Brand: Amtrol(28)91Tue, Dec 31 – Fri, Jan 3Add to List -
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Add to ListAdd to ListWX-203 (146S30), 32 Gal. WELL-X-TROL Well Tank WX-203 WX-203 (146S30), 32 Gal. WELL-X-TROL Well TankSKU: WX-203Brand: Amtrol(65)Add to List -
![WX-255 (149S147), 81 Gal. WELL-X-TROL Well Tank Product Image]()
Add to ListAdd to ListWX-255 (149S147), 81 Gal. WELL-X-TROL Well Tank WX-255 WX-255 (149S147), 81 Gal. WELL-X-TROL Well TankSKU: WX-255Brand: Amtrol(29)67Tue, Dec 31 – Fri, Jan 3Add to List -
![WX-202 (144S29), 20 Gal. WELL-X-TROL Well Tank Product Image]()
Add to ListAdd to ListWX-202 (144S29), 20 Gal. WELL-X-TROL Well Tank WX-202 WX-202 (144S29), 20 Gal. WELL-X-TROL Well TankSKU: WX-202Brand: Amtrol(54)Add to List -
![RP-15HP, 20 Gal<br>Residential Pressuriser Product Image]()
Add to ListAdd to ListRP-15HP, 20 Gal Residential Pressuriser 2201-39 RP-15HP, 20 Gal Residential PressuriserSKU: 2201-39Brand: Amtrol(9)15Tue, Dec 31 – Fri, Jan 3Add to List -
![WX-251 (145S10), 62 Gal. WELL-X-TROL Well Tank Product Image]()
Add to ListAdd to ListWX-251 (145S10), 62 Gal. WELL-X-TROL Well Tank WX-251 WX-251 (145S10), 62 Gal. WELL-X-TROL Well TankSKU: WX-251Brand: Amtrol(32)15Tue, Dec 31 – Fri, Jan 3Add to List -
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![THERM-X-TROL ST-25V Expansion Tank<br>(10.3 Gallon) Product Image]()
Add to ListAdd to ListTHERM-X-TROL ST-25V Expansion Tank (10.3 Gallon) 143N164 THERM-X-TROL ST-25V Expansion Tank (10.3 Gallon)SKU: 143N164Brand: Amtrol(7)Add to List -
![WX-202XL (144S240)<br>26 Gal. WELL-X-TROL<br>Well Tank Product Image]()
Add to ListAdd to ListWX-202XL (144S240) 26 Gal. WELL-X-TROL Well Tank WX-202XL WX-202XL (144S240) 26 Gal. WELL-X-TROL Well TankSKU: WX-202XLBrand: Amtrol(43)Add to List -
![WX-205 (147S44)<br>34 Gal. WELL-X-TROL Product Image]()
Add to ListAdd to ListWX-205 (147S44) 34 Gal. WELL-X-TROL WX-205 WX-205 (147S44) 34 Gal. WELL-X-TROLSKU: WX-205Brand: Amtrol(20)Add to List -
![RP-25HP, 34 Gal<br>Residential Pressuriser Product Image]()
Add to ListAdd to ListRP-25HP, 34 Gal Residential Pressuriser 2201-28 RP-25HP, 34 Gal Residential PressuriserSKU: 2201-28Brand: Amtrol(1)Add to List -
![WX-252 (145S20), 86 Gal. WELL-X-TROL Well Tank Product Image]()
Add to ListAdd to ListWX-252 (145S20), 86 Gal. WELL-X-TROL Well Tank WX-252 WX-252 (145S20), 86 Gal. WELL-X-TROL Well TankSKU: WX-252Brand: Amtrol(6)26Tue, Dec 31 – Fri, Jan 3Add to List -
![WX-250 (145S1), 44 Gal<br>WELL-X-TROL Well Tank<br>w/ Durabase Stand Product Image]()
Add to ListAdd to ListWX-250 (145S1), 44 Gal WELL-X-TROL Well Tank w/ Durabase Stand WX-250D WX-250 (145S1), 44 Gal WELL-X-TROL Well Tank w/ Durabase StandSKU: WX-250DBrand: Amtrol(6)Add to List -
![WX-255 (149S147), 81 Gal<br>WELL-X-TROL Well Tank<br>w/ Durabase Stand Product Image]()
Add to ListAdd to ListWX-255 (149S147), 81 Gal WELL-X-TROL Well Tank w/ Durabase Stand WX-255D WX-255 (149S147), 81 Gal WELL-X-TROL Well Tank w/ Durabase StandSKU: WX-255DBrand: Amtrol(2)16Tue, Dec 31 – Fri, Jan 3Add to List -
![THERM-X-SPAN T-5 Expansion Tank<br>(2 Gallon) Product Image]()
Add to ListAdd to ListTHERM-X-SPAN T-5 Expansion Tank (2 Gallon) 140735 THERM-X-SPAN T-5 Expansion Tank (2 Gallon)SKU: 140735Brand: Amtrol(13)Add to List -
![WX1-302 (150S92)<br>86 Gal. WELL-X-TROL<br>Well-X1 Well Tank (Blue) Product Image]()
Add to ListAdd to ListWX1-302 (150S92) 86 Gal. WELL-X-TROL Well-X1 Well Tank (Blue) WX1-302 WX1-302 (150S92) 86 Gal. WELL-X-TROL Well-X1 Well Tank (Blue)SKU: WX1-302Brand: Amtrol(3)Add to List -
![WX-101 (140PR1)<br>2 Gal. WELL-X-TROL<br>In-Line Well Tank Product Image]()
Add to ListAdd to ListWX-101 (140PR1) 2 Gal. WELL-X-TROL In-Line Well Tank WX-101 WX-101 (140PR1) 2 Gal. WELL-X-TROL In-Line Well TankSKU: WX-101Brand: Amtrol(15)Add to List -
![THERM-X-TROL ST-8 Expansion Tank Product Image]()
Add to ListAdd to ListTHERM-X-TROL ST-8 Expansion Tank 140N738 THERM-X-TROL ST-8 Expansion TankSKU: 140N738Brand: Amtrol(15)Add to List -
![WX-203 (146S30), 32 Gal<br>WELL-X-TROL Well Tank<br>w/ Durabase Stand Product Image]()
Add to ListAdd to ListWX-203 (146S30), 32 Gal WELL-X-TROL Well Tank w/ Durabase Stand WX-203D WX-203 (146S30), 32 Gal WELL-X-TROL Well Tank w/ Durabase StandSKU: WX-203DBrand: Amtrol(4)Add to List -
![WX-350 (151S1), 119 Gal<br>WELL-X-TROL Well Tank<br>w/ Durabase Stand Product Image]()
Add to ListAdd to ListWX-350 (151S1), 119 Gal WELL-X-TROL Well Tank w/ Durabase Stand WX-350D WX-350 (151S1), 119 Gal WELL-X-TROL Well Tank w/ Durabase StandSKU: WX-350DBrand: Amtrol(2)Add to List -
![THERM-X-TROL ST-60V Expansion Tank<br>(34 Gallon) Product Image]()
Add to ListAdd to ListTHERM-X-TROL ST-60V Expansion Tank (34 Gallon) 147N130 THERM-X-TROL ST-60V Expansion Tank (34 Gallon)SKU: 147N130Brand: AmtrolAdd to List -
![WX-103 (142PR1)<br>7.6 Gal. WELL-X-TROL<br>In-Line Well Tank Product Image]()
Add to ListAdd to ListWX-103 (142PR1) 7.6 Gal. WELL-X-TROL In-Line Well Tank WX-103 WX-103 (142PR1) 7.6 Gal. WELL-X-TROL In-Line Well TankSKU: WX-103Brand: Amtrol(5)Add to List -
![THERM-X-TROL ST-30V Expansion Tank<br>(14 Gallon) Product Image]()
Add to ListAdd to ListTHERM-X-TROL ST-30V Expansion Tank (14 Gallon) 143N273 THERM-X-TROL ST-30V Expansion Tank (14 Gallon)SKU: 143N273Brand: Amtrol(7)Add to List -
![WX-102 (141PR1)<br>4.4 Gal. WELL-X-TROL<br>In-Line Well Tank Product Image]()
Add to ListAdd to ListWX-102 (141PR1) 4.4 Gal. WELL-X-TROL In-Line Well Tank WX-102 WX-102 (141PR1) 4.4 Gal. WELL-X-TROL In-Line Well TankSKU: WX-102Brand: Amtrol(16)Add to List -
![WX-201 (143S29), 14 Gal. WELL-X-TROL Well Tank Product Image]()
Add to ListAdd to ListWX-201 (143S29), 14 Gal. WELL-X-TROL Well Tank WX-201 WX-201 (143S29), 14 Gal. WELL-X-TROL Well TankSKU: WX-201Brand: Amtrol(3)Add to List
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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