#1 Home Improvement Retailer

Internet # 321133682

Model # FTET21-N

Store SKU # 1007986609

2.1 Gal. Thermal Expansion Tank for Potable Water Heater

Apply Now
Pay $32.32 after $25 OFF your total qualifying purchase upon opening a new card. info
Apply for a Home Depot Consumer Card
0 in stock
Free & Easy Returns In Store or Online
Return this item within 90 days of purchase. Read Return Policy

Product Details

About This Product

Thermal Expansion Tanks are designed for pressure control in potable water systems. The tank uses compressed air to maintain system pressures by accepting and expelling the changing volume of water as it heats and cools. It prevents the water heater pressure relief valve from opening, saves energy and eliminates a potential safety hazard. It is commonly installed in a domestic hot water system that contains a backflow preventer, a check valve or a pressure reducing valve. Measures: 11 in. L x 7.9 in. W x 11 in. H with 2.1 Gal. tank size, 6 lbs. weight and 3/4 in. connection size (NPT).


  • Protected pre-charge valve eliminates potential leak path
  • Prevents dangerous pressure build up, protects household appliances and fixtures
  • External baked epoxy-polyester coating provides a durable appliance finish
  • Exclusive polypropylene liner eliminates internal corrosion
  • MIG welding eliminates interior rough spots and sharp edges
  • All tanks are NSF61 certified
  • Each tank is factory leak tested
  • 150 psi maximum pressure rating
  • Maximum operating pressure: 150 psi
  • Operating temperature: 210°F
  • Factory pre-charge: 40 psi
  • Shell: carbon steel
  • Connection: stainless steel
  • Diaphragm: butyl
  • Color: almond
  • 1-year warranty
  • Return Policy
  • California residents
     see Prop 65 WARNINGS

Product Information

Internet # 321133682

Model # FTET21-N

Store SKU # 1007986609


Dimensions: H 11 in, W 7.9 in, D 11 in


Product Depth (in.)

11 in

Product Height (in.)

11 in

Product Width (in.)

7.9 in



Water Heater

Compatible Brand/Model

The Plumber's Choice

Finish Family



Carbon Steel

Nominal Tank Capacity (gallons)

2 gal

Pack Size


Product Weight (lb.)

6 lb



Warranty / Certifications

Manufacturer Warranty

1 Year

Questions & Answers

Q:I have a FTET21 purchased Feb t 2019 that is water logged. My information shows it has a five year warranty. I do not find any contact information regarding how to file a warranty claim. How do I do this?
by|Jan 21, 2023
1 Answer
Answer This Question

A:  You would need to contact Home Depot regarding this.

by|Apr 25, 2023
    Q:Can this tank be mounted vertically with the air valve at the top, water connection at the bottom?
    by|Nov 28, 2022
    1 Answer
    Answer This Question

    A:  Please consult with a local plumber.

    by|Mar 8, 2024
      1 found this answer helpful
      Q:Does the tank have a shreader valve so you can add pressure behind the bladder in the tank? Or is the pressure preset at the factory? If so what is the bladder pressure set at at the factory?
      by|Sep 18, 2022
      1 Answer
      Answer This Question

      A:  Factory recharge is 40 PSI

      by|Sep 19, 2022
        Showing 1-3 of 3

        Customer Reviews

        5 out of 5

        • 5 out of 2 reviews
        • 100% recommend this product
        Filter by:
        Showing 1-2 of 2 reviews
        • Verified Purchase
        We're very happy.
        We had absolutely no problem installing the Expansion Tank. It has been working beautifully.
        • Verified Purchase
        • Recommended
        Showing 1-2 of 2 reviews