Skip to the beginning of the images gallery

Zilmet ZS2, .53 Gallon, Inline Stainless Steel Expansion Tank

Be the first to review this product

MSRP $360.50

Sale Price $180.25

50% OFF Factory Direct Saving

SKU#

ZS2

In stock

ZS2

Key Features

• 0.53-gallon inline expansion tank for domestic heating or central heating system use, helping maintain stable pressure

• 304 stainless steel shell and connection

• Fixed butyl membrane suitable for potable water applications

• 1/2 inch NPTM connection

• Compact design helps avoid sediment trapping and bacterial growth

• Designed for applications where hygiene is important

• Suitable for coastal areas and harsh chemical environments where plain steel can corrode

• Factory precharged at 50 PSI

• Maximum operating pressure of 150 PSI

• Can be installed where a compact footprint matters

• Easy to check during routine system service as part of the normal maintenance process; if service questions come up, refer to the boiler or system manual

• Tank sizing can vary depending on system requirements

• Common expansion tank sizes are often measured in gallons

• Best performance depends on proper installation location

• Make sure the unit is located where it remains accessible

• In systems where conditions require it, periodic draining may be considered as part of maintenance

• Timely replacement helps prevent pressure-related issues by catching water-quality or performance change before it leads to more trouble

• Built to resist premature wear in demanding conditions

• Helps reduce the risk of pressure-related system repair costs

• 5-year limited warranty

Overview

Zilmet has over 50 years of experience manufacturing expansion tanks, producing more than 5 million tanks and 1 million heat exchangers annually with full vertical integration, including its own diaphragms and bladders. The Zilmet ZS2 is a .53 gallon inline stainless steel expansion vessel built for homeowners, contractors, and property managers who need a compact, hygienic tank for potable water and domestic heating system use.

The Zilmet ZS2 features a 304 stainless steel shell and connection and is rated for pressure management and thermal expansion control in closed systems, with capacity sized to match total heating system volume for safer pressure control in boiler and closed-loop heating applications where heated water can expand and increase water pressure. In a central heating system, its purpose is to help stabilize pressure as temperature changes, with the internal air cushion compressing as heated water expands to protect components from stress in domestic heating systems, residential plumbing systems, and potable water installations where controlling pressure spikes, reducing system stress on pipes, and protecting water quality are essential. Expansion tanks absorb excess pressure from thermal expansion and help maintain pressure in heating systems to prevent damage, reduce risk, and support long-term reliability and efficiency. This model is intended for a closed-system type, not an open vessel design.

Zilmet’s compact design uses a fixed butyl membrane and a seamless diaphragm that does not stretch or crease, allowing cleaner operation with no bubbles or corners to trap sediment or air and helping inhibit bacterial growth.

Benefits of Installation at the Highest Point

• Stainless steel construction helps resist corrosion, with key components working together and the sealed design making pressure control more dependable

• Compact design minimizes areas where sediment can collect; a sealed diaphragm keeps air and water separated, with water on one side, and unlike an open tank installed at the highest point of a vented system, this design helps ensure cleaner operation

• Fixed butyl membrane supports potable water use

• Not the open-tank style historically common in the UK

• For exact placement details, refer to the boiler manual or installer guidance

• Factory precharge of 50 PSI

Specifications

More Information
Drawdown @ 40/60 PSI	0.5
Drawdown @ 30/50 PSI	0.7
Discharge Connection	1/2" NPTM
Material	Stainless Steel
Capacity	.53
Size	5.5" x 7.7"
Source	https://www.zilmetusa.com/
Model #	ZS2
Manufacturer	Zilmet
Performance Chart	None
Shipping Weight	5
Warranty	5 Year Limited

Reviews

Write Your Own Review

Product Literature

Zilmet Inox-Pro Stainless Steel Expansion Tank Specifications

(Size: 0.23 MB)

zilmet_nsf61.pdf

(Size: 0.11 MB)

FAQs

What is the capacity of the Zilmet ZS2?

The tank has a .53 gallon capacity.

What connection size does this tank use?

It has a 1/2 inch NPTM connection.

What materials are used in the tank construction?

The shell and connection are 304 stainless steel, and the fixed membrane is butyl.

Is the membrane suitable for potable water applications?

Yes, the butyl membrane is listed for potable water applications.

What is the maximum operating pressure?

The maximum operating pressure is 150 PSI.

What is the factory precharge setting?

The factory precharge is 36 PSI.

What applications is this expansion tank described for?

It is described for domestic heating systems with boilers or heat exchangers and for applications where hygiene is important.

Is this tank intended for harsh or coastal environments?

Yes, it is described as suitable for coastal areas and harsh chemical environments where plain steel can corrode.

Installation Tips

Installation Brief

The Zilmet ZS2 is an inline expansion tank that should be installed with the system depressurized and connected according to the product connection size.