---
product_id: 221379594
title: "Watts ETX-30 4.5 Gallon Non-potable Water Expansion Tank for Heating and Cooling Systems. 1/2 In. MNPT Connection to Supply Piping"
brand: "watts"
price: "€ 128.36"
currency: EUR
in_stock: false
reviews_count: 5
url: https://www.desertcart.hr/products/221379594-watts-etx-30-4-5-gallon-non-potable-water-expansion
store_origin: HR
region: Croatia
---

# Max temp 240°F 1/2" MNPT connection 4.5 gal capacity Watts ETX-30 4.5 Gallon Non-potable Water Expansion Tank for Heating and Cooling Systems. 1/2 In. MNPT Connection to Supply Piping

**Brand:** watts
**Price:** € 128.36
**Availability:** ❌ Out of Stock

## Summary

> 🔥 Stay cool under pressure with Watts ETX-30 – the expansion tank pros trust!

## Quick Answers

- **What is this?** Watts ETX-30 4.5 Gallon Non-potable Water Expansion Tank for Heating and Cooling Systems. 1/2 In. MNPT Connection to Supply Piping by watts
- **How much does it cost?** € 128.36 with free shipping
- **Is it available?** Currently out of stock
- **Where can I buy it?** [www.desertcart.hr](https://www.desertcart.hr/products/221379594-watts-etx-30-4-5-gallon-non-potable-water-expansion)

## Best For

- watts enthusiasts

## Why This Product

- Trusted watts brand quality
- Free international shipping included
- Worldwide delivery with tracking
- 15-day hassle-free returns

## Key Features

- • **Precharged at 12 PSI:** Ready to install for instant, reliable pressure control.
- • **Compact & Easy Install:** Space-saving design with quick 1/2" MNPT threaded connection.
- • **Universal Compatibility:** Works seamlessly with glycol and various hydronic heating systems.
- • **Durable Steel Construction:** Built to last with rugged alloy steel and flexible diaphragm.
- • **Robust 4.5 Gallon Capacity:** Handle thermal expansion with ease and reduce system stress.

## Overview

The Watts ETX-30 is a 4.5-gallon precharged expansion tank designed for closed loop hydronic heating and cooling systems. Featuring durable alloy steel construction and a flexible diaphragm, it controls thermal expansion and maintains system pressure up to 75 PSI. Compatible with glycol systems and rated for temperatures up to 240°F, it installs easily via a 1/2" MNPT connection, making it a reliable upgrade for residential and commercial heating setups.

## Description

Non-potable water expansion tanks are 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. The pre-pressurized steel tank features a durable expansion membrane that prevents contact of the water with the air in the tank. This rugged diaphragm minimizes loss of the air change and ensures long and trouble-free life for the system. Model ETX mounts to supply piping. Maximum Pressure: 75psi (5.3 bar) for ETX. 4.7 gallon For closed loop hydronic piping system 1/2" male pipe thread Used on closed loop hydronic system piping to control thermal expansion of hot water Accepts increased volume of eater created when the system water is heated Steel construction Rugged flexible diaphragm Compact size Compatible with gylcol systems Hydrostatic test pressure 75 PSI Maximum temperature 240 fahrenheit Maximum pressure 60 PSI Pre-charged at 12 PSI For use on finned tube baseboard from 25,000 BTU to 150,000 BTU, Convectors & unit heaters from 75,000 BTU to up to 100,000 BTU, Cast iron radiators from 50,000 BTU to 100,000 BTU & cast iron baseboards up to 50,000 BTU net boiler output.

Review: Item replaced original. Works great.
Review: 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.

## Features

- The product is easy to use
- Compatible with glycol in systems
- The product is manufactured in China
- Precharged (field adjustable) to 12 psi

## Technical Specifications

| Specification | Value |
|---------------|-------|
| ASIN | B0086DDNEI |
| Batteries Required? | No |
| Batteries included? | No |
| Customer Reviews | 4.6 4.6 out of 5 stars (563) |
| Date First Available | 10 Jun. 2010 |
| Included Components | Expansion Tank |
| Item Package Quantity | 1 |
| Item Weight | 3.63 kg |
| Item model number | ETX-30 |
| Manufacturer | Watts |
| Material | Alloy Steel |
| Part Number | ETX-30 |
| Product Dimensions | 27.43 x 28.19 x 37.59 cm; 3.63 kg |
| Wattage | 30 watts |

## Product Details

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

## Images

![Watts ETX-30 4.5 Gallon Non-potable Water Expansion Tank for Heating and Cooling Systems. 1/2 In. MNPT Connection to Supply Piping - Image 1](https://m.media-amazon.com/images/I/21OkKRNrqpL.jpg)
![Watts ETX-30 4.5 Gallon Non-potable Water Expansion Tank for Heating and Cooling Systems. 1/2 In. MNPT Connection to Supply Piping - Image 2](https://m.media-amazon.com/images/I/314b2FCEcqL.jpg)
![Watts ETX-30 4.5 Gallon Non-potable Water Expansion Tank for Heating and Cooling Systems. 1/2 In. MNPT Connection to Supply Piping - Image 3](https://m.media-amazon.com/images/I/31EvqfcfBsL.jpg)
![Watts ETX-30 4.5 Gallon Non-potable Water Expansion Tank for Heating and Cooling Systems. 1/2 In. MNPT Connection to Supply Piping - Image 4](https://m.media-amazon.com/images/I/31MI68yvVJL.jpg)
![Watts ETX-30 4.5 Gallon Non-potable Water Expansion Tank for Heating and Cooling Systems. 1/2 In. MNPT Connection to Supply Piping - Image 5](https://m.media-amazon.com/images/I/31S8jZxm45L.jpg)

## Customer Reviews

### ⭐⭐⭐⭐⭐ Review
*by A***R on 15 May 2021*

Item replaced original. Works great.

### ⭐⭐⭐⭐⭐ Review
*by W**** on 8 March 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.

### ⭐⭐⭐⭐⭐ Review
*by K***S on 23 December 2023*

Worked perfectly.

## 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 Croatia*
*Store origin: HR*
*Last updated: 2026-02-28*