Water heater part ยท TT FLEX

TT FLEX ET-20G-1/2 Expansion Tank

Water heater part

Water heater part

Updated October 2026

The short answer

A well-specified water heater part for installing or servicing a tankless heater.

Delivers
Water heater part.
Watch for
Fit depends on the heater model.
Suits
Installing or servicing a tankless heater.
Tank
2 gal
Dimensions (seller)
3.3"W x 4.55"H
Prices change often; the button shows today's price.

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What it delivers

The TT FLEX ET-20G-1/2 Expansion Tank is a water heater part.

Match the part to the exact heater model and its manual before ordering.

Tank volume, per the listing: 2 gal.

Expansion tanks are sized to the system's volume and pressure; relief valves to the heater's rating. Match the part to the heater's manual and local code.

Listed details: model: ET-20G-1/2.

The listing gives dimensions of 3.3 in (W) x 4.55 in (H).

Right unit for this house?

Install it when

  • Installing or servicing a tankless heater
  • Matching a part named in the manual

Look at another unit when

  • Heaters it doesn't name

Strengths and trade-offs

Strengths

  • Water heater part

Trade-offs

  • Fit depends on the heater model

Install limits

  • Figures are the maker's or seller's own. Flow at a rise is our estimate from the input; gas, venting and electrical work needs a licensed professional.

Rated performance

Every figure below comes from the source shown in brackets. Where the maker doesn't state something, we say so instead of estimating.

Model numberET-20G-1/2Retailer
Tank2 galRetailer
Dimensions (seller)3.3"W x 4.55"HRetailer
Features (seller)Dual-Function Design: Thermal Expansion Protection & Water Hammer SuppressionRetailer

Rival units at this flow

More venting and install parts rated for similar demand

Full venting and install parts spec grid

Final verdict

A well-specified water heater part for installing or servicing a tankless heater.

Buy this unit

Our links open this exact model's product page. Prices and stock change; check what's included before you order.

Prices change often; the button shows today's price.

Each button opens this exact model. We may earn a commission on tracked links; it never changes what we publish. Disclosure

Questions buyers ask

Will the TT FLEX ET-20G-1/2 Expansion Tank fit my heater?
Only if its listing or maker names your heater model or series. Check the part number in your heater's installation manual.