--- product_id: 4811296 title: "Watts 0590715 1/8\" FV-4M1 Automatic Float Vent" brand: "watts water technologies" price: "£25.01" currency: GBP in_stock: true reviews_count: 8 category: "Watts Water Technologies" url: https://www.desertcart.co.uk/products/4811296-watts-0590715-1-8-fv-4m1-automatic-float-vent store_origin: GB region: United Kingdom --- # 240°F max temp tolerance 150 PSI max pressure High-temp polyethylene float Watts 0590715 1/8" FV-4M1 Automatic Float Vent **Brand:** watts water technologies **Price:** £25.01 **Availability:** ✅ In Stock ## Summary > 🔥 Keep your heating system whisper-quiet and worry-free with Watts FV-4M1! ## Quick Answers - **What is this?** Watts 0590715 1/8" FV-4M1 Automatic Float Vent by watts water technologies - **How much does it cost?** £25.01 with free shipping - **Is it available?** Yes, in stock and ready to ship - **Where can I buy it?** [www.desertcart.co.uk](https://www.desertcart.co.uk/products/4811296-watts-0590715-1-8-fv-4m1-automatic-float-vent) ## Best For - watts water technologies enthusiasts ## Why This Product - Trusted watts water technologies brand quality - Free international shipping included - Worldwide delivery with tracking - 15-day hassle-free returns ## Key Features - • **Silent Efficiency:** Automatically vents air to eliminate noise and boost heating efficiency - • **Maintenance Made Easy:** Disassembles quickly for inspection and cleaning, ensuring long-term performance - • **Heat-Resistant Mastery:** Operates flawlessly in temperatures up to 240°F, perfect for glycol systems - • **Compact & Durable Design:** Brass construction with a sleek 3.4x2x2 inch profile fits discreetly in any setup - • **Pressure-Proof Performance:** Handles up to 150 PSI for robust system reliability ## Overview The Watts 0590715 FV-4M1 Automatic Float Vent is a compact, brass-built valve engineered for commercial and residential hydronic heating systems. Rated for pressures up to 150 PSI and temperatures up to 240°F, it features a high-temp polyethylene float and automatic air venting to enhance system efficiency and silence. Easy to install and maintain, it’s ideal for glycol systems and designed to prevent air-related heating issues, ensuring smooth, reliable operation. ## Description The Watts FV-4 Series automatic air vent valve is designed for both commercial and residential hydronic heating systems, ensuring efficient air removal in hot or cold water distribution systems. This valve is crucial for maintaining system performance by automatically venting air that can cause issues such as noise and reduced efficiency. The valve is highly versatile, with a high-temperature rating making it suitable for glycol systems and as an anti-vacuum device. It is engineered to handle the separation and dispersal of air while fluid circulates through the system, which helps to maintain smooth and effective operation. Key features include a 1/8" bottom tap and a 1/8" NPT male threaded inlet, allowing for easy installation and integration into existing systems. The valve is pressure rated up to 150 PSI (10 bar) and can handle temperatures up to 240°F (116°C). For ease of maintenance, the valve can be disassembled for inspection and cleaning, ensuring longevity and consistent performance. Constructed from durable brass, the Watts FV-4 Series valve is built to withstand the demands of light commercial and residential hydronic heating applications. The float mechanism is made from high-temperature resistant polyethylene, enhancing reliability and extending the valve's service life.At Watts, our family of brands offers one of the most varied product lines in the world. Simply put, if you're moving, removing, heating, treating, or reusing water, we have everything you need to get the job done. Everything we design is made to keep the Earth's most precious resource safer, cleaner, and more useful for our customers. From melting ice on entire city blocks from the ground up, to filtering safe drinking water in isolated, weather disaster zones, you need water and water needs Watts. Review: Does its job perfectly. Easy installation. - I purchased this as a replacement to a 10 year old "snifter" style float vent that was beginning a slow weeping leak. The new valve is much more solid and it has required absolutely no attention beyond the initial loosening of the vent cap as prescribed by the installation instructions. I used a Teflon based pipe thread paste on the male threads, being careful not to get any near the opening. No leaks and what's really wonderful, my hot water system has vented itself so that it is almost completely silent when the heat comes up. It usually surprises me when established designs get a working update that is beyond cosmetic and this is one of those times. I was so pleased with the purchase I replaced another snifter at the far end of the system with another one of these. Review: Works Great - Before I bought this, I could not get the air out of my hydronic baseboard system. I would hear gurggling when the heat ran and it ran for long periods of time with the baseboard units not getting very hot. Added this air vent and immediately heard it venting the air until the pipes filled with water. Just turn the top know open 2 turns. Also, needed to empty the system of water for a repair and the unit acts as a vacuum breaker allowing air to enter the system when water is not at the valve. Best part is it’s a solid piece of plumbing and it’s small enough to fit inside my baseboard covers. ## Features - Maximum Pressure: 150 psi (10 bar) - Temperature Range: 33F - 240F (5C - 116C) - Float is high temperature resistant polyethylene - Suitable for use with glycol systems - Impurities do not usually affect function as maximum float line of water is always lower than the valve seal ## Technical Specifications | Specification | Value | |---------------|-------| | ASIN | B000MINF34 | | Best Sellers Rank | #131,662 in Industrial & Scientific ( See Top 100 in Industrial & Scientific ) #169 in Float Valves | | Brand | Watts Water Technologies | | Date First Available | August 17, 2005 | | Exterior Finish | Brass | | Inlet Connection Type | National Pipe Tapered | | Is Discontinued By Manufacturer | No | | Item Weight | 4.8 ounces | | Item dimensions L x W x H | 3.4 x 2 x 2 inches | | Item model number | 0590715 | | Manufacturer | Watts | | Material | Brass | | Maximum Operating Pressure | 150 Pound per Square Inch | | Number of Ports | 2 | | Outlet Connection Type | FNPT | | Product Dimensions | 3.4 x 2 x 2 inches | | Specification Met | ISO 9001 | | UPC | 098268373622 783961246471 733353359555 | ## Product Details - **Brand:** Watts Water Technologies - **Exterior Finish:** Brass - **Inlet Connection Type:** National Pipe Tapered - **Item dimensions L x W x H:** 3.4 x 2 x 2 inches - **Manufacturer:** Watts - **Material:** Brass - **Maximum Operating Pressure:** 150 Pound per Square Inch - **Number of Ports:** 2 - **Outlet Connection Type:** FNPT - **Specification Met:** ISO 9001 ## Images ![Watts 0590715 1/8" FV-4M1 Automatic Float Vent - Image 1](https://m.media-amazon.com/images/I/71xWIQYvR9L.jpg) ## Questions & Answers **Q: What is the size of the male fitting that scews into my system? Thank you!** A: the male fitting on this vent valve is 1/8" npt. the outer diameter of the male thread is approx. 5/16" . the picture of the one i bought was quite deceiving. didn't look anything like the one i got, but it did fit. **Q: it came with a plastic tab in the 1/8" threads,,, is that supposed to be screwed into the line** A: What do the instructions have to say about the tab? Anything? If you didn't receive any instructional information with the valve, then I suppose you purchased from the wrong seller because Watts typically provides some installation paperwork with their valves. **Q: Put two of these in my upstairs which is on a separate zone from the rest of house and now the heat no longer works. Any suggestions?** A: I agree with GSV, Lyle, and Jake. Make sure your circulation pump is running, all zone valves are open. Do you have heat in the rest of the house? If no heat, make sure your burner is coming on. And make sure you have power to your zone valves so that they are opening. And that your air bleeder valves are a couple turns open.If all of these issues are solved, then Lyle 's suggestion may be the problem and the bleeder valve may be drawing air in instead of pushing it out. **Q: I just had one of these installed on my new boiler system but there is no black cap on the top.Will it still bleed out the air automatically,** A: Yes it will still bleed ## Customer Reviews ### ⭐⭐⭐⭐⭐ Does its job perfectly. Easy installation. *by R***N on December 6, 2017* I purchased this as a replacement to a 10 year old "snifter" style float vent that was beginning a slow weeping leak. The new valve is much more solid and it has required absolutely no attention beyond the initial loosening of the vent cap as prescribed by the installation instructions. I used a Teflon based pipe thread paste on the male threads, being careful not to get any near the opening. No leaks and what's really wonderful, my hot water system has vented itself so that it is almost completely silent when the heat comes up. It usually surprises me when established designs get a working update that is beyond cosmetic and this is one of those times. I was so pleased with the purchase I replaced another snifter at the far end of the system with another one of these. ### ⭐⭐⭐⭐⭐ Works Great *by B***E on October 30, 2021* Before I bought this, I could not get the air out of my hydronic baseboard system. I would hear gurggling when the heat ran and it ran for long periods of time with the baseboard units not getting very hot. Added this air vent and immediately heard it venting the air until the pipes filled with water. Just turn the top know open 2 turns. Also, needed to empty the system of water for a repair and the unit acts as a vacuum breaker allowing air to enter the system when water is not at the valve. Best part is it’s a solid piece of plumbing and it’s small enough to fit inside my baseboard covers. ### ⭐⭐⭐⭐⭐ Works for pool filter *by D***6 on May 23, 2021* I saw a couple of reviews that folks were using this to vent their pool pumps. I installed it in line with my pool pressure gauge and it works great. When I turn on the pump it hisses out the air and then shuts off automatically. I left the manual air release in place too, in case I need it. I double checked and there was no air left in the filter vessel. So much more convenient than a manual release and WAY cheaper than the plastomatic ARV valves we use at work ($300+), for the price of one of those I can buy 20 of these! ## Frequently Bought Together - Watts 0590715 1/8" FV-4M1 Automatic Float Vent - Hydro Master Automatic Air Vent Valve 1/8 Inch Brass - Taco 400-4 1/8-Inch-NPT Float Air Hy-Vent --- ## Why Shop on Desertcart? - 🛒 **Trusted by 1.3+ Million Shoppers** — Serving international shoppers since 2016 - 🌍 **Shop Globally** — Access 737+ million products across 21 categories - 💰 **No Hidden Fees** — All customs, duties, and taxes included in the price - 🔄 **15-Day Free Returns** — Hassle-free returns (30 days for PRO members) - 🔒 **Secure Payments** — Trusted payment options with buyer protection - ⭐ **TrustPilot Rated 4.5/5** — Based on 8,000+ happy customer reviews **Shop now:** [https://www.desertcart.co.uk/products/4811296-watts-0590715-1-8-fv-4m1-automatic-float-vent](https://www.desertcart.co.uk/products/4811296-watts-0590715-1-8-fv-4m1-automatic-float-vent) --- *Product available on Desertcart United Kingdom* *Store origin: GB* *Last updated: 2026-05-16*