Water heater part ยท SUPPLYGIANT

SUPPLYGIANT MTET-GUU3 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
Confirm the part number first.
Suits
Installing or servicing a tankless heater.
Tank
2 gal
Material
Stainless Steel
Dimensions (seller)
3.1"W x 4.35"H
Product weight
4.8 ounces
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

What it delivers

The SUPPLYGIANT MTET-GUU3 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: features: Thermal Expansion Protection; material: Stainless Steel; model: MTET-GUU3.

The listing gives dimensions of 3.1 in (W) x 4.35 in (H) and a weight of 4.8 ounces.

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

  • Confirm the part number first

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 numberMTET-GUU3Retailer
Tank2 galRetailer
Dimensions (seller)3.1"W x 4.35"HRetailer
Features (seller)Thermal Expansion ProtectionRetailer
Product weight4.8 ouncesRetailer
MaterialStainless SteelRetailer

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 SUPPLYGIANT MTET-GUU3 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.