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53 (1)
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Expansion Tanks

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Expansion Tanks

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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.

This product will NOT be used in the installation or repair of a potable water (human consumption) application.

You must agree to this statement in order to purchase this product.

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This Item is Non-Returnable

When you order this item, we then special order it for you from the manufacturer. Therefore, our standard return policy does not apply to this item. Manufacturer's warranty still applies.

I understand that once I order this item I cannot cancel or return it.

You must agree to this statement in order to purchase this product.

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Certification Necessary

FlashShield is to be installed only by a licensed plumber/HVAC installer that has successfully completed the Gastite/FlashShield certification test.

By checking this box I am acknowledging that I have successfully completed the Gastite/FlashShield certification and I hold a valid Gastite/FlashShield certification card.

You must agree to this statement in order to purchase this product.

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Warning

This product must be installed by a qualified/licensed contractor and set up with properly calibrated combustion test equipment. Failure to comply with this could result in substantial property damage, severe personal injury or death.

By checking this box I am verifying that this product will be installed by a qualified/licensed contractor and will be set up with properly calibrated combustion test equipment.

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Compare

THERM-X-TROL ST-5 Expansion Tank

SKU: 140N43

Brand: Amtrol

(46)

$45.95 each

$176.60 box of 4

$44.15 each

277

Thu, Jun 27

277

Qty Arrives

277 Thu, Jun 27

Questions? Call 1-888-757-4774
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THERM-X-TROL ST-12 Expansion Tank

SKU: 141N43

Brand: Amtrol

(34)

$61.45 each

$235.80 box of 4

$58.95 each

241

Thu, Jun 27

241

Qty Arrives

241 Thu, Jun 27

Questions? Call 1-888-757-4774
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PLT-5, 2.1 Gallon Potable Water Expansion Tank

SKU: 0067370

Brand: Watts

(6)

$39.55 each

439

Thu, Jun 27

439

Qty Arrives

439 Thu, Jun 27

Questions? Call 1-888-757-4774
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WX-350 (151S1) 119 Gal. WELL-X-TROL Well Tank

SKU: WX-350

Brand: Amtrol

(17)

$1,019.95 each

$1,958.30 box of 2

$979.15 each

44

Mon, Jul 1 – Wed, Jul 3

44

Qty Arrives

44 Mon, Jul 1 – Wed, Jul 3

Questions? Call 1-888-757-4774
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WX-250 (145S1), 44 Gal. WELL-X-TROL Well Tank

SKU: WX-250

Brand: Amtrol

(68)

$515.95 each

$990.70 box of 2

$495.35 each

87

Thu, Jun 27

87

Qty Arrives

87 Thu, Jun 27

Questions? Call 1-888-757-4774
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WX-302 (150S1), 86 Gal. WELL-X-TROL Well Tank

SKU: WX-302

Brand: Amtrol

(26)

$709.95 each

$1,363.10 box of 2

$681.55 each

41

Mon, Jul 1 – Wed, Jul 3

41

Qty Arrives

41 Mon, Jul 1 – Wed, Jul 3

Questions? Call 1-888-757-4774
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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

132

Thu, Jun 27

132

Qty Arrives

132 Thu, Jun 27

Questions? Call 1-888-757-4774
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WX-255 (149S147), 81 Gal. WELL-X-TROL Well Tank

SKU: WX-255

Brand: Amtrol

(27)

$759.95 each

$1,459.10 box of 2

$729.55 each

50

Mon, Jul 1 – Wed, Jul 3

50

Qty Arrives

50 Mon, Jul 1 – Wed, Jul 3

Questions? Call 1-888-757-4774
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WX-202 (144S29), 20 Gal. WELL-X-TROL Well Tank

SKU: WX-202

Brand: Amtrol

(48)

$229.95 each

$441.50 box of 2

$220.75 each

51

Thu, Jun 27

51

Qty Arrives

51 Thu, Jun 27

Questions? Call 1-888-757-4774
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RP-15HP, 20 Gal Residential Pressuriser

SKU: 2201-39

Brand: Amtrol

(9)

$1,299.95 each

$2,495.90 box of 2

$1,247.95 each

21

Mon, Jul 1 – Wed, Jul 3

21

Qty Arrives

21 Mon, Jul 1 – Wed, Jul 3

Questions? Call 1-888-757-4774
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WX-251 (145S10), 62 Gal. WELL-X-TROL Well Tank

SKU: WX-251

Brand: Amtrol

(32)

$775.95 each

$1,489.90 box of 2

$744.95 each

45

Mon, Jul 1 – Wed, Jul 3

45

Qty Arrives

45 Mon, Jul 1 – Wed, Jul 3

Questions? Call 1-888-757-4774
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RP-10HP, 14 Gal Residential Pressuriser

SKU: 2201-37

Brand: Amtrol

(2)

$1,025.95 each

$1,969.90 box of 2

$984.95 each

14

Thu, Jun 27

14

Qty Arrives

14 Thu, Jun 27

Questions? Call 1-888-757-4774
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THERM-X-TROL ST-25V Expansion Tank (10.3 Gallon)

SKU: 143N164

Brand: Amtrol

(7)

$149.95 each

$431.85 box of 3

$143.95 each

135

Thu, Jun 27

135

Qty Arrives

135 Thu, Jun 27

Questions? Call 1-888-757-4774
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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

28

Thu, Jun 27

28

Qty Arrives

28 Thu, Jun 27

Questions? Call 1-888-757-4774
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WX-205 (147S44) 34 Gal. WELL-X-TROL

SKU: WX-205

Brand: Amtrol

(18)

$429.95 each

$825.50 box of 2

$412.75 each

10

Thu, Jun 27

10

Qty Arrives

10 Thu, Jun 27

Questions? Call 1-888-757-4774
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RP-25HP, 34 Gal Residential Pressuriser

SKU: 2201-28

Brand: Amtrol

(1)

$1,779.95 each

2

Mon, Jul 1 – Wed, Jul 3

2

Qty Arrives

2 Mon, Jul 1 – Wed, Jul 3

Questions? Call 1-888-757-4774
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WX-252 (145S20), 86 Gal. WELL-X-TROL Well Tank

SKU: WX-252

Brand: Amtrol

(6)

$975.95 each

$1,873.90 box of 2

$936.95 each

13

Mon, Jul 1 – Wed, Jul 3

13

Qty Arrives

13 Mon, Jul 1 – Wed, Jul 3

Questions? Call 1-888-757-4774
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WX-250 (145S1), 44 Gal WELL-X-TROL Well Tank w/ Durabase Stand

SKU: WX-250D

Brand: Amtrol

(5)

$529.95 each

7

Thu, Jun 27

7

Qty Arrives

7 Thu, Jun 27

Questions? Call 1-888-757-4774
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WX-255 (149S147), 81 Gal WELL-X-TROL Well Tank w/ Durabase Stand

SKU: WX-255D

Brand: Amtrol

(2)

$759.95 each

5

Mon, Jul 1 – Wed, Jul 3

5

Qty Arrives

5 Mon, Jul 1 – Wed, Jul 3

Questions? Call 1-888-757-4774
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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

73

Thu, Jun 27

73

Qty Arrives

73 Thu, Jun 27

Questions? Call 1-888-757-4774
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WX1-302 (150S92) 86 Gal. WELL-X-TROL Well-X1 Well Tank (Blue)

SKU: WX1-302

Brand: Amtrol

(2)

$1,024.95 each

1

Mon, Jul 1 – Wed, Jul 3

1

Qty Arrives

1 Mon, Jul 1 – Wed, Jul 3

Questions? Call 1-888-757-4774
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WX-101 (140PR1) 2 Gal. WELL-X-TROL In-Line Well Tank

SKU: WX-101

Brand: Amtrol

(14)

$72.95 each

$280.20 box of 4

$70.05 each

22

Thu, Jun 27

22

Qty Arrives

22 Thu, Jun 27

Questions? Call 1-888-757-4774
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THERM-X-TROL ST-8 Expansion Tank

SKU: 140N738

Brand: Amtrol

(13)

$55.55 each

$213.40 box of 4

$53.35 each

30

Thu, Jun 27

30

Qty Arrives

30 Thu, Jun 27

Questions? Call 1-888-757-4774
Compare

WX-203 (146S30), 32 Gal WELL-X-TROL Well Tank w/ Durabase Stand

SKU: WX-203D

Brand: Amtrol

(3)

$489.95 each

24

Thu, Jun 27

24

Qty Arrives

24 Thu, Jun 27

Questions? Call 1-888-757-4774
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WX-350 (151S1), 119 Gal WELL-X-TROL Well Tank w/ Durabase Stand

SKU: WX-350D

Brand: Amtrol

(1)

$1,265.95 each

Tue, Jul 23 – Thu, Aug 1

Arrives

Tue, Jul 23 – Thu, Aug 1

Questions? Call 1-888-757-4774 or Chat Us
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THERM-X-TROL ST-60V Expansion Tank (34 Gallon)

SKU: 147N130

Brand: Amtrol

$319.95 each

14

Thu, Jun 27

14

Qty Arrives

14 Thu, Jun 27

Questions? Call 1-888-757-4774
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WX-103 (142PR1) 7.6 Gal. WELL-X-TROL In-Line Well Tank

SKU: WX-103

Brand: Amtrol

(5)

$159.95 each

$460.65 box of 3

$153.55 each

17

Thu, Jun 27

17

Qty Arrives

17 Thu, Jun 27

Questions? Call 1-888-757-4774
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THERM-X-TROL ST-30V Expansion Tank (14 Gallon)

SKU: 143N273

Brand: Amtrol

(7)

$209.95 each

$604.65 box of 3

$201.55 each

24

Thu, Jun 27

24

Qty Arrives

24 Thu, Jun 27

Questions? Call 1-888-757-4774
Compare

WX-102 (141PR1) 4.4 Gal. WELL-X-TROL In-Line Well Tank

SKU: WX-102

Brand: Amtrol

(13)

$109.95 each

$422.20 box of 4

$105.55 each

16

Thu, Jun 27

16

Qty Arrives

16 Thu, Jun 27

Questions? Call 1-888-757-4774
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WX-201 (143S29), 14 Gal. WELL-X-TROL Well Tank

SKU: WX-201

Brand: Amtrol

(3)

$244.95 each

$470.30 box of 2

$235.15 each

11

Thu, Jun 27

11

Qty Arrives

11 Thu, Jun 27

Questions? Call 1-888-757-4774

Qty	Arrives
277	Thu, Jun 27

Qty	Arrives
241	Thu, Jun 27

Qty	Arrives
439	Thu, Jun 27

Qty	Arrives
44	Mon, Jul 1 – Wed, Jul 3

Qty	Arrives
87	Thu, Jun 27

Qty	Arrives
41	Mon, Jul 1 – Wed, Jul 3

Qty	Arrives
132	Thu, Jun 27

Qty	Arrives
50	Mon, Jul 1 – Wed, Jul 3

Qty	Arrives
51	Thu, Jun 27

Qty	Arrives
21	Mon, Jul 1 – Wed, Jul 3

Qty	Arrives
45	Mon, Jul 1 – Wed, Jul 3

Qty	Arrives
14	Thu, Jun 27

Qty	Arrives
135	Thu, Jun 27

Qty	Arrives
28	Thu, Jun 27

Qty	Arrives
10	Thu, Jun 27

Qty	Arrives
2	Mon, Jul 1 – Wed, Jul 3

Qty	Arrives
13	Mon, Jul 1 – Wed, Jul 3

Qty	Arrives
7	Thu, Jun 27

Qty	Arrives
5	Mon, Jul 1 – Wed, Jul 3

Qty	Arrives
73	Thu, Jun 27

Qty	Arrives
1	Mon, Jul 1 – Wed, Jul 3

Qty	Arrives
22	Thu, Jun 27

Qty	Arrives
30	Thu, Jun 27

Qty	Arrives
24	Thu, Jun 27

Arrives
Tue, Jul 23 – Thu, Aug 1

Qty	Arrives
14	Thu, Jun 27

Qty	Arrives
17	Thu, Jun 27

Qty	Arrives
24	Thu, Jun 27

Qty	Arrives
16	Thu, Jun 27

Qty	Arrives
11	Thu, Jun 27

Resources

Videos

How Expansion Tanks Work

Calculators

Expansion Tank Size Calculator

Articles

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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