Shop Klein Tools

Filters

91 items
Reset

SORT

Top Sellers
Default
Price ▲
Price ▼

Product Availability

Show In Stock Only (39)

Brand

Amtrol (50)
Axiom (4)
Bluefin (4)
Flamco (1)
Holdrite (1)
Sioux Chief (6)
Storm King Enterprises (2)
Watts (5)
Zilmet (15)
Zurn (3)

Tank Volume

0.04 Gallons (1)
0.13 Gallons (1)
0.26 Gallons (1)
0.53 Gallons (1)
2 Gallons (3)
2.1 Gallons (3)
3.2 Gallons (2)
4.4 Gallons (2)
4.5 Gallons (1)
4.8 Gallons (2)
See More

Review Score

(28)
(3)
(1)

Price Range

$5 to $10 (2)
$10 to $15 (2)
$15 to $20 (2)
$30 to $35 (2)
$35 to $40 (2)
$40 to $45 (3)
$45 to $50 (3)
$50 to $60 (2)
$60 to $70 (3)
$70 to $80 (2)
See More

Water Heater Expansion Tanks

Help Face
Need a little help?
View our Resources
91 items
Grid
List
Order Fast Track Logo items by 6PM, receive tomorrow

Resources

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.
Questions?
MondayThursday
8am7:45pm
Friday
9am7:45pm
SaturdaySunday
9am5:45pm

Available 8am
Available 8am
Available 8am
Response by Thurs

or check out our Support Center
Compare
THERM-X-TROL ST-5 Expansion Tank
THERM-X-TROL ST-5 Expansion Tank
SKU: 140N43
Amtrol
SKU: 140N43
Brand: Amtrol
(96)
$62.48 each
Get 301 by Thu, Jul 25
More Available
Get 301 by Thu, Jul 25
More Available
Compare
THERM-X-TROL ST-12 Expansion Tank
THERM-X-TROL ST-12 Expansion Tank
SKU: 141N43
Amtrol
SKU: 141N43
Brand: Amtrol
(65)
$86.49 each
Get 58 by Thu, Jul 25
More Available
Get 58 by Thu, Jul 25
More Available
Compare
PLT-5, 2.1 Gallon Potable Water Expansion Tank
PLT-5, 2.1 Gallon Potable Water Expansion Tank
SKU: 0067370
Watts
SKU: 0067370
Brand: Watts
(30)
$79.26 each
Get 103 by Thu, Jul 25
More Available
Get 103 by Thu, Jul 25
More Available
Compare
RP-15HP, 20 Gal Residential Pressuriser
RP-15HP, 20 Gal Residential Pressuriser
SKU: 2201-39
Amtrol
SKU: 2201-39
Brand: Amtrol
(16)
$2,231.00 each
Get 7 by Thu, Jul 25 - Mon, Jul 29
More Available
Get 7 by Thu, Jul 25 - Mon, Jul 29
More Available
Compare
RP-10HP, 14 Gal Residential Pressuriser
RP-10HP, 14 Gal Residential Pressuriser
SKU: 2201-37
Amtrol
SKU: 2201-37
Brand: Amtrol
(12)
$2,275.20 each
Get 8 by Thu, Jul 25 - Mon, Jul 29
More Available
Get 8 by Thu, Jul 25 - Mon, Jul 29
More Available
Compare
THERM-X-TROL ST-25V Expansion Tank (10.3 Gallon Volume)
$271.04 each
Get 56 by Thu, Jul 25
More Available
Get 56 by Thu, Jul 25
More Available
Compare
10.3 Gallon Vertical Expansion Tank
10.3 Gallon Vertical Expansion Tank
SKU: EX10V
Bluefin
SKU: EX10V
Brand: Bluefin
(2)
$181.55 each
Get 10 by Thu, Jul 25
More Available
Get 10 by Thu, Jul 25
More Available
Compare
2 Gallon Expansion Tank
2 Gallon Expansion Tank
SKU: EX2
Bluefin
SKU: EX2
Brand: Bluefin
(6)
$42.22 each
Get 121 by Thu, Jul 25
More Available
Get 121 by Thu, Jul 25
More Available
Compare
4.5 Gallon Expansion Tank
4.5 Gallon Expansion Tank
SKU: EX4
Bluefin
SKU: EX4
Brand: Bluefin
(6)
$60.07 each
Get 1,493 by Thu, Jul 25
More Available
Get 1,493 by Thu, Jul 25
More Available
Compare
3.2 Gallon Expansion Tank
3.2 Gallon Expansion Tank
SKU: EX3
Bluefin
SKU: EX3
Brand: Bluefin
(6)
$56.09 each
Get 6 by Thu, Jul 25
More Available
Get 6 by Thu, Jul 25
More Available
Compare
RP-25HP, 34 Gal Residential Pressuriser
RP-25HP, 34 Gal Residential Pressuriser
SKU: 2201-28
Amtrol
SKU: 2201-28
Brand: Amtrol
(2)
$3,370.74 each
Get 5 by Thu, Jul 25 - Mon, Jul 29
More Available
Get 5 by Thu, Jul 25 - Mon, Jul 29
More Available
Compare
THERM-X-SPAN T-5 Expansion Tank (2 Gallon Volume)
$44.15 each
Get 394 by Thu, Jul 25
More Available
Get 394 by Thu, Jul 25
More Available
Compare
THERM-X-TROL ST-60V Expansion Tank (34 Gallon Volume)
$572.16 each
Get 15 by Thu, Jul 25
More Available
Get 15 by Thu, Jul 25
More Available
Compare
THERM-X-TROL ST-30V Expansion Tank (14 Gallon Volume)
$344.87 each
Get 6 by Thu, Jul 25
More Available
Get 6 by Thu, Jul 25
More Available
Compare
THERM-X-TROL ST-42V Expansion Tank (20 Gallon Volume)
$410.36 each
Get 9 by Thu, Jul 25
More Available
Get 9 by Thu, Jul 25
More Available
Compare
THERM-X-TROL ST-80V Expansion Tank (44 Gallon Volume)
$785.64 each
Get it by Thu, Aug 22 - Fri, Sep 20
Get it by Thu, Aug 22 - Fri, Sep 20
Compare
THERM-X-SPAN T-12 Expansion Tank (4.4 Gallon Volume)
$62.50 each
Get 139 by Thu, Jul 25
More Available
Get 139 by Thu, Jul 25
More Available
Compare
THERM-X-TROL ASME ST-30V-C Expansion Tank
$2,318.87 each
Get it by Fri, Aug 23 - Wed, Sep 25
Get it by Fri, Aug 23 - Wed, Sep 25
Compare
THERM-X-TROL ST-1 Expansion Tank (Matte Tan)
$31.54 each
Get 30 by Thu, Jul 25
More Available
Get 30 by Thu, Jul 25
More Available
Compare
QuickStrap Expansion Tank Mounting Bracket (5 Gal. Capacity)
$16.89 each
Get 416 by Thu, Jul 25
More Available
Get 416 by Thu, Jul 25
More Available
Compare
11" HydroClaw Expansion Tank Support Bracket
$45.38 each
Get 214 by Thu, Jul 25
More Available
Get 214 by Thu, Jul 25
More Available
Compare
Expansion Tank Wall Bracket (Pro Kit w/ ETV-1)
$115.29 each