Product images: Amazon listings
Written from the listing's specs, not from our own use · How we rate
2.1 gallons of expansion room is the headline feature of the HeSun TANK001-1 Expansion Tank (2.1 gal). A good match for a closed system with a check valve or a pressure regulator, rated 6.0/10 on its documented specs.
| Brand | HeSun |
|---|---|
| Category | Service kits, valves & parts |
| Connection | 3/4" MNPT |
| ASIN | B0GTQ4Y7JW |
Full listing title: 1PC HeSun 2.1 Gallon(8L) 3/4" MNPT Thermal Expansion Tank(TANK001-1)
Rated from the listing's specs, no buyer reviews yet
What it's made for: a closed system with a check valve or a pressure regulator.
Two expansion tanks close to it on our rating, each with a dated price.
The size the listing states. On a closed system it takes up the water that expands as it heats; set the air charge to your house pressure with a tire gauge before it goes on.
Yes, if your house has a check valve or a pressure regulator at the meter: that makes it a closed system, and expanding hot water needs somewhere to go. This one holds 2.1 gallons, per the listing.
Maybe not, on an open system. Local codes differ, so your plumber has the last word.
What the HeSun TANK001-1 Expansion Tank (2.1 gal) listing names:
Check these figures against your heater's manual before you order.
On Sep 30, 2026, that price put it around the middle of the 6 expansion tanks we have a recent price for.
The button opens the exact listing (ASIN B0GTQ4Y7JW), where today's price, stock and seller apply.
A bigger system? The Watts ETX-30 Expansion Tank, 4.5 gal (7.0/10) holds 4.5 gallons.
Our take
The best thing about the HeSun TANK001-1 Expansion Tank (2.1 gal) is 2.1 gallons of expansion room. No buyer has reviewed it yet, so our 6.0/10 comes from the spec sheet alone. The catch with this HeSun expansion tank: the air charge has to be set to your house pressure first, or it does little. We'd pick it if your plumbing has a check valve or a pressure regulator; otherwise, put it next to the EFIELD TANK001 Expansion Tank (2.1 gal) first.
Before you order the HeSun TANK001-1 Expansion Tank (2.1 gal), check your water pressure: it holds 2.1 gallons, and the air charge has to match your house pressure.
Usually yes when there is a check valve or a pressure regulator at the meter; your plumber or local code decides.
It holds 2.1 gallons. The tank size follows your water pressure and the volume of hot water in the system; small residential systems often use the 2-gallon class.
Match the air charge to your house water pressure before it goes on the line.
How the HeSun TANK001-1 Expansion Tank (2.1 gal) stacks up against the closest alternative, the EFIELD TANK001 Expansion Tank (2.1 gal).
| Criterion | HeSun TANK001-1 Expansion Tank, 2.1 gal | EFIELD TANK001 Expansion Tank, 2.1 gal |
|---|---|---|
| Our rating | 6.0/10 | 6.2/10 |
| Size | 2.1 gal | 2.1 gal |
Pick the EFIELD TANK001 Expansion Tank (2.1 gal) if you want our higher-rated option (6.2/10).
We rate it 6.0/10 (fair). The rating comes from its documented listing alone, as no customer-review record is captured yet.
Its listing states 2.1 gallons of expansion room. These are the seller's figures, not our measurements: whether it fits your exact heater is worth confirming first.
Do you need one: usually yes when there is a check valve or a pressure regulator at the meter; your plumber or local code decides. Size: it holds 2.1 gallons. The tank size follows your water pressure and the volume of hot water in the system; small residential systems often use the 2-gallon class. Air charge: match the air charge to your house water pressure before it goes on the line.
We link to the exact listing on Amazon, where today's price, stock and seller apply. It is an affiliate link, and it has no effect on the rating.
No, we haven't used it ourselves. Everything on this page comes from its listing, read line by line and weighed with our published formula.