---
product_id: 52389645
title: "Flamco Flexvent 1/2\" Floatvent c/w shut-off valve - Automatic Air Vent 27740"
brand: "flamco"
price: "฿3082"
currency: THB
in_stock: true
reviews_count: 13
category: "Flamco"
url: https://www.desertcart.co.th/products/52389645-flamco-flexvent-1-2-floatvent-c-w-shut-off-valve
store_origin: TH
region: Thailand
---

# Automatic air vent with float valve Operates up to 120°C peak temp Compact 1/2 inch threaded design Flamco Flexvent 1/2" Floatvent c/w shut-off valve - Automatic Air Vent 27740

**Brand:** flamco
**Price:** ฿3082
**Availability:** ✅ In Stock

## Summary

> 💡 Elevate your heating system with the Flexvent 1/2 – where precision meets durability!

## Quick Answers

- **What is this?** Flamco Flexvent 1/2" Floatvent c/w shut-off valve - Automatic Air Vent 27740 by flamco
- **How much does it cost?** ฿3082 with free shipping
- **Is it available?** Yes, in stock and ready to ship
- **Where can I buy it?** [www.desertcart.co.th](https://www.desertcart.co.th/products/52389645-flamco-flexvent-1-2-floatvent-c-w-shut-off-valve)

## Best For

- flamco enthusiasts

## Why This Product

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

## Key Features

- • **Built to Endure:** Handles pressures up to 10 bar and temperatures peaking at 120°C for reliable performance.
- • **Premium Brass Finish:** Durable brass construction resists corrosion and guarantees long-lasting quality.
- • **Seamless Integration:** Ultra-compact 1/2 inch threaded valve fits effortlessly into any heating system.
- • **Precision Air Management:** Automatic float valve ensures continuous, maintenance-free air bleeding to optimize system efficiency.
- • **Factory-Tested Reliability:** Each unit undergoes rigorous testing to ensure flawless operation from day one.

## Overview

The Flamco Flexvent 1/2 inch is a compact, brass automatic air vent valve designed for residential heating systems with glycol content up to 50%. It supports operating temperatures up to 90°C (120°C peak) and pressures up to 6 bar (10 bar peak). Featuring a float valve mechanism and protective chamber to prevent dirt ingress, it ensures efficient air bleeding and system reliability. Factory-tested and built to last, it’s the professional choice for seamless, maintenance-free heating system performance.

## Description

Free delivery and returns on all eligible orders. Shop Flamco Flexvent 1/2" Floatvent c/w shut-off valve - Automatic Air Vent 27740.

Review: Does exactly what it says on the box - Purchased this to replace the old barrel design plastic air vent on my central heating system that was leaking. It took considerably more effort to bleed and refill the system (and getting rid of the subsequent air locks), than to fit this. A couple of layers of white plumbers tape, and it fitted perfectly without any leaks. It is clearly better built than the plastic valve as well, and operates much better. Although it doesn't come with any instructions, if you download the Flamco manual it recommends that you loosen the cap before filling the system and tighten afterwards. The location of the valve is critical as well, it should be on the highest point of the system after the water pump to prevent air being drawn into the system. While not a "Silver bullet" for a central heating system with an airlock issue, the Flamco was not designed to be that. There are many reasons for airlocks occurring in a domestic CH scenario, and an airvent valve may or may not be the solution. If you purchase it as a replacement part with this in mind, you won't go wrong.
Review: Good quality - Great

## Features

- The Flamco Flexvent 1/2 inch vent valve is suitable for house installations with a glycol content of up to 50%.
- Thanks to its extremely compact shape, the Flexvent 1/2 inch bleed valve can be easily installed in any system that can be installed at a temperature below 90°C (with a peak of max. 120°C) and a pressure of 6 bar (with a peak of max. 10 bar).
- As a quality guarantee, every Flamco nozzle is tested before it leaves our factory.
- The Flexvent seal seat is protected from dirt as the protective chamber is placed on the float

## Technical Specifications

| Specification | Value |
|---------------|-------|
| ASIN | B00GXNNGPY |
| Best Sellers Rank | 61,861 in DIY & Tools ( See Top 100 in DIY & Tools ) 446 in Central Heating System Accessories |
| Brand | Flamco |
| Connector Type | Threaded |
| Customer Reviews | 4.5 4.5 out of 5 stars (1,218) |
| Exterior Finish | Brass |
| Included Components | No |
| Inlet Connection Size | 230 Millimeters |
| Inlet Connection Type | 1/2" Male Thread |
| Item Dimensions | 23 x 3 x 80 centimetres |
| Item Type Name | Flamco Flexvent R1/2 inch Radiator Bleeder Automatic, Float Vent Heater, Quick Bleed, Thermostatic Valve, Flexvent Vent 27740 |
| Item Weight | 100 Grams |
| Manufacturer | Flamco |
| Material | Messing |
| Maximum Pressure | 10 Bars |
| Model Number | 27740 |
| Number of Ports | 2 |
| Outlet Connection Size | 0.5 Inches |
| Outlet Connection Type | External thread |
| Part Number | 27740 |
| Set Name | Flamco Flexvent 1/2" Floatvent 27740 |
| Size | R½" |
| Specification Met | CE, ISO 9001, RoHS |
| Thread Size | 1/2 Zoll |
| Thread Type | 1/2 inch |
| Unit Count | 1.0 count |
| Valve Type | Float Valve |

## Product Details

- **Brand:** Flamco
- **Exterior finish:** Brass
- **Inlet connection size:** 230 Millimeters
- **Inlet connection type:** 1/2" Male Thread
- **Item dimensions L x W x H:** 23 x 3 x 80 centimetres
- **Material:** Messing
- **Maximum operating pressure:** 10 Bars
- **Number of ports:** 2
- **Outlet connection size:** 0.5 Inches
- **Outlet connection type:** External thread

## Images

![Flamco Flexvent 1/2" Floatvent c/w shut-off valve - Automatic Air Vent 27740 - Image 1](https://m.media-amazon.com/images/I/61yr+SH6UIL.jpg)
![Flamco Flexvent 1/2" Floatvent c/w shut-off valve - Automatic Air Vent 27740 - Image 2](https://m.media-amazon.com/images/I/61RwBdg60BL.jpg)
![Flamco Flexvent 1/2" Floatvent c/w shut-off valve - Automatic Air Vent 27740 - Image 3](https://m.media-amazon.com/images/I/61H44UExJbL.jpg)
![Flamco Flexvent 1/2" Floatvent c/w shut-off valve - Automatic Air Vent 27740 - Image 4](https://m.media-amazon.com/images/I/61rK058ZPRL.jpg)
![Flamco Flexvent 1/2" Floatvent c/w shut-off valve - Automatic Air Vent 27740 - Image 5](https://m.media-amazon.com/images/I/6109MtGcANL.jpg)

## Available Options

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

## Questions & Answers

**Q: Hello - does this connect directly to 15mm copper pipe or does it need an adaptor?**
A: Hi, it has a 1/2" BSP male thread, so you would need an adaptor to fit it onto 15mm copper.

**Q: Can I screw this straight into the top of my towel rail replacing the manual bleed valve? Will I need ptfe tape?**
A: This type of valve isn't really designed for what you are proposing, more to remove air from whole systems. You may wish to consider one of the smaller valves specifically designed for radiators. Try "Aladdin Micro Barlo 6mm Fully Automatic Self Bleeding Radiator Valve" or perhaps have a chat with your local plumbers' merchant.

**Q: what is the Product Dimensions?**
A: Flexvent Dimensions
Ø [mm]: 30
H. [mm]: 75.5

Connection
R 1⁄2"

**Q: Does the valve need to be fitted vertically**
A: As the CH water lifts a plunger against gravity, if the valve was other than upright, it may not operate to its full capacity

## Customer Reviews

### ⭐⭐⭐⭐⭐ Does exactly what it says on the box
*by L***G on 4 October 2020*

Purchased this to replace the old barrel design plastic air vent on my central heating system that was leaking. It took considerably more effort to bleed and refill the system (and getting rid of the subsequent air locks), than to fit this. A couple of layers of white plumbers tape, and it fitted perfectly without any leaks. It is clearly better built than the plastic valve as well, and operates much better. Although it doesn't come with any instructions, if you download the Flamco manual it recommends that you loosen the cap before filling the system and tighten afterwards. The location of the valve is critical as well, it should be on the highest point of the system after the water pump to prevent air being drawn into the system. While not a "Silver bullet" for a central heating system with an airlock issue, the Flamco was not designed to be that. There are many reasons for airlocks occurring in a domestic CH scenario, and an airvent valve may or may not be the solution. If you purchase it as a replacement part with this in mind, you won't go wrong.

### ⭐⭐⭐⭐⭐ Good quality
*by R***A on 5 April 2025*

Great

### ⭐⭐⭐⭐ It's 1/2 inch and comes with a closure valve.
*by M***F on 21 December 2019*

Easy to install and seems to work. Give it 4 weeks and I'll come back and buy a few more if it successfully clears air buildup in my manifolds.

## Frequently Bought Together

- Flamco Flexvent 1/2" Floatvent c/w shut-off valve - Automatic Air Vent 27740
- LOCTITE 55 Pipe Thread Sealant, Non Curing Thread Sealant for Plumbing Pipes and Fittings, Reliable Fast Action Pipe Sealant for Metal and Plastic, 50m

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*Product available on Desertcart Thailand*
*Store origin: TH*
*Last updated: 2026-04-28*