---
product_id: 4811297
title: "ETX-30 4.5 Gal Carbon Steel Expansion Tank Hydronic Heating 75psi | Volume 4.7 Gallons 1/2\" Mnpt Pre-Charged 12 Psi Maximum 60 Psi Epoxy Finish Closed Loop Hydronic Heating System Piping"
price: "947.72 DT"
currency: TND
in_stock: true
reviews_count: 13
url: https://www.desertcart.tn/products/4811297-etx-30-4-5-gal-carbon-steel-expansion-tank-hydronic
store_origin: TN
region: Tunisia
---

# 1/2" MNPT connection 60 psi max pressure 4.5 gal capacity ETX-30 4.5 Gal Carbon Steel Expansion Tank Hydronic Heating 75psi | Volume 4.7 Gallons 1/2" Mnpt Pre-Charged 12 Psi Maximum 60 Psi Epoxy Finish Closed Loop Hydronic Heating System Piping

**Price:** 947.72 DT
**Availability:** ✅ In Stock

## Summary

> 🔥 Keep your heating system cool under pressure with Watts ETX-30! 🛠️

## Quick Answers

- **What is this?** ETX-30 4.5 Gal Carbon Steel Expansion Tank Hydronic Heating 75psi | Volume 4.7 Gallons 1/2" Mnpt Pre-Charged 12 Psi Maximum 60 Psi Epoxy Finish Closed Loop Hydronic Heating System Piping
- **How much does it cost?** 947.72 DT with free shipping
- **Is it available?** Yes, in stock and ready to ship
- **Where can I buy it?** [www.desertcart.tn](https://www.desertcart.tn/products/4811297-etx-30-4-5-gal-carbon-steel-expansion-tank-hydronic)

## Best For

- Customers looking for quality international products

## Why This Product

- Free international shipping included
- Worldwide delivery with tracking
- 15-day hassle-free returns

## Key Features

- • **Pre-Charged at 12 PSI:** Ready to install, maintaining optimal system pressure from day one.
- • **Robust Carbon Steel Build:** Epoxy finish ensures durability and long-lasting performance.
- • **Versatile & Easy Mounting:** Direct supply pipe mounting with standard tire valve charging for hassle-free setup.
- • **Generous 4.5 Gallon Volume:** Handles thermal expansion with ease, reducing system stress.
- • **Max Pressure Rating of 60 PSI:** Built to withstand high-pressure fluctuations, protecting your heating system.

## Overview

The Watts ETX-30 is a 4.5-gallon carbon steel expansion tank designed for closed loop hydronic heating systems. Pre-charged at 12 psi and rated for up to 60 psi, it controls thermal expansion to prevent overpressure, ensuring system longevity and efficiency. Its durable epoxy finish and easy 1/2" MNPT mounting make it a reliable, professional-grade solution for both residential and commercial heating setups.

## Description

Product Description The Watts Non-Potable Water Expansion Tank, with a generous 4.5-gallon volume, is expertly designed for use in both commercial and residential closed loop hydronic heating systems. Its primary function is to control the thermal expansion of hot water, ensuring that system pressure remains below the relief setting of the relief valve and preventing overpressure situations.Constructed from high-quality carbon steel with a durable epoxy finish, this expansion tank is built to last. The tank features an expansion membrane that effectively minimizes the loss of the air charge, guaranteeing a long and trouble-free operational life for the entire heating system.The design of this water expansion tank allows for straightforward installation, as it mounts directly to the supply piping. It includes a 1/2" MNPT system connection and a 0.302-32" charging valve connection, which is a standard tire valve, facilitating easy on-site charging and maintenance.Pre-charged at 12 psi, this expansion tank is ready for immediate integration. With a maximum pressure rating of 60 psi, the Watts Non-Potable Water Expansion Tank is capable of handling significant pressure fluctuations. It works seamlessly in conjunction with hot water heaters to absorb increased water volume, thus preventing system overpressure. This feature not only ensures the safety of the system but also enhances its efficiency and longevity. Whether in a residential or commercial setting, this expansion tank provides a reliable solution for managing the thermal expansion of non-potable water in closed loop hydronic heating systems. From the Manufacturer Use the Watts series ETX water expansion tank in tandem with your hot water heater to absorb increased water volume resulting from hot water boiler heating and keep system pressure below the relief setting. Use in closed-loop, non potable water heating systems. Durable steel tank with 60 psi maximum working pressure.

Review: Perfect Fit and Replacement. Watts is what you need!! - Perfect Fit and replacement. Purchased the EXT-30 to replace my failed Flextrol expansion tank purchased 12/2020. Apparently the bladder failed, causing my hydronic heating system to increase pressure causing the pressure pop off valve to drip. The old tank was small, 2.1 gallon size. When researching replacements, I accidently ordered the 4.5 gallon. Thankfully it just barely fit. I have three zones and fingers crossed the larger capacity will endure less stress during the repeating thermo cycling. Watts tank is well built, came pre charged at 12 psi. Spun right on 1/2 mnpt connection. Ordered on Monday, delivered Wednesday and 30 minutes later was installed. Pressures have maintained, no leaks, and zero worries. Btw, I called the plumbing supply store where I purchased the Flextrol in 2020, I believe it was less than 100 bucks, wanted a whopping $150.
Review: Better pricing - Easy to install. Better pricing than from the Big Box store. Good quality.

## Features

- WATER EXPANSION TANK: With a generous 4.5 tank gallon volume, the Watts Non-Potable Water Expansion Tank is designed for use in commercial and residential closed loop hydronic heating system piping to control the thermal expansion of hot water and maintain system pressure below the relief setting of the relief valve.
- DURABLE CONSTRUCTION: This tank is constructed from high-quality carbon steel with an epoxy finish, ensuring long-lasting performance. It is also equipped with a durable expansion membrane that minimizes the loss of the air charge.
- VERSATILE MOUNTING: This tank is designed for easy installation, mounting directly to the supply piping. It features a 1/2" MNPT system connection and a 0.302-32" charging valve connection (standard tire valve) to facilitate on-site charging.
- HIGH PRESSURE CAPACITY: Pre-charged at 12 psi, this expansion tank is built to withstand the demands of hydronic heating systems, boasting a maximum pressure rating of 60 psi. It works in tandem with hot water heaters to absorb increased water volume, preventing system overpressure and ensuring the longevity and efficiency of the heating system.
- EVERY DROP COUNTS: Water. It's in our name and close to our hearts. Since 1874, Watts Water Technologies has been delivering innovative technologies that make the world's most precious resource safe and accessible. Everything we design is made to keep the Earth's most precious resource safer, cleaner, and more useful for our customers. Our family of brands offers one of the most varied product lines in the world, with world-class, water-related solutions.

## Technical Specifications

| Specification | Value |
|---------------|-------|
| Customer Reviews | 4.6 out of 5 stars 615 Reviews |

## Product Details

- **Brand:** Watts
- **Product Dimensions:** 10.5"W x 14.8"H
- **Color:** Gray
- **Wattage:** 30 watts
- **Style:** Non-Potable

## Images

![ETX-30 4.5 Gal Carbon Steel Expansion Tank Hydronic Heating 75psi | Volume 4.7 Gallons 1/2" Mnpt Pre-Charged 12 Psi Maximum 60 Psi Epoxy Finish Closed Loop Hydronic Heating System Piping - Image 1](https://m.media-amazon.com/images/I/51mEF4g1JWL.jpg)

## Available Options

This product comes in different **Size, Style** options.

## Customer Reviews

### ⭐⭐⭐⭐⭐ Perfect Fit and Replacement. Watts is what you need!!
*by W**** on March 8, 2025*

Perfect Fit and replacement. Purchased the EXT-30 to replace my failed Flextrol expansion tank purchased 12/2020. Apparently the bladder failed, causing my hydronic heating system to increase pressure causing the pressure pop off valve to drip. The old tank was small, 2.1 gallon size. When researching replacements, I accidently ordered the 4.5 gallon. Thankfully it just barely fit. I have three zones and fingers crossed the larger capacity will endure less stress during the repeating thermo cycling. Watts tank is well built, came pre charged at 12 psi. Spun right on 1/2 mnpt connection. Ordered on Monday, delivered Wednesday and 30 minutes later was installed. Pressures have maintained, no leaks, and zero worries. Btw, I called the plumbing supply store where I purchased the Flextrol in 2020, I believe it was less than 100 bucks, wanted a whopping $150.

### ⭐⭐⭐⭐⭐ Better pricing
*by P***N on August 14, 2025*

Easy to install. Better pricing than from the Big Box store. Good quality.

### ⭐⭐⭐⭐⭐ Direct-fit replacement
*by R***N on October 19, 2025*

This is a great replacement for my old expansion tank. The old tank worked for at least 16 years until the bladder split. This one is a direct-fit replacement and now my boiler heat system is back up and running.

## Frequently Bought Together

- Watts ETX-30 Non-Potable Water Carbon Steel Expansion Tank for Closed Loop Hydronic Heating System Piping, 1/2" MNPT Connection, Tank Volume 4.7 Gallons, Maximum Pressure 75 psi
- Taco 400-4 1/8-Inch-NPT Float Air Hy-Vent
- Watts 0342691 30 PSI Pressure Relief Valve, Bronze, 3/4" 335 M2-030

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*Product available on Desertcart Tunisia*
*Store origin: TN*
*Last updated: 2026-09-03*