Union Air Release Valve Assembly

Every water circulation system-heating, cooling, or supply-deals with three recurring problems:

1. Air trapped in the system
Air accumulates at high points, blocking flow, causing noise, and reducing heat transfer. Without proper venting, radiators stay cold, pumps cavitate, and efficiency drops.

2. Water that needs to be drained
For maintenance, repairs, or seasonal shutdown, the system must be drained. Without a drain point, installers must break pipe connections-messy, time-consuming, and risky.

3. Sediment and debris that accumulate
Sand, rust, scale, and sludge settle at low points. Without a blowdown point, debris builds up, restricting flow and accelerating corrosion.

The conventional solution: Install three separate components-an air vent at the high point, a drain valve at the low point, and a blowdown valve for sediment removal. Three components = three installation points + six threaded connections + three maintenance schedules.

The Yunnl solution: One component, one installation point, three functions. The 3‑in‑1 combination air release valve integrates air vent, drain valve, and blowdown valve into a single compact brass assembly.

This union air release valve assembly is a specialized plumbing fitting designed to expel trapped air and gas from circulating water systems. By removing accumulated air inside pipelines, it guarantees smooth media flow and improves overall system operating efficiency.

Manufactured from heavy‑duty brass with corrosion‑resistant textured finish, this unit comes with multiple practical connection interfaces. It includes threaded ends for pipe integration, a quick‑connect hose port, plus a manual shut‑off lever for easy on‑site operation.

The top is fitted with an adjustable knob and a lanyard‑tethered sealing cap to prevent accidental loss. It reliably vents trapped air inside water lines, which is critical to stabilize system pressure, reduce pipeline noise and avoid blockages. Widely applied in residential, commercial and industrial water circulation pipelines. Compact integrated construction simplifies installation and delivers consistent long‑term performance.

1.Forged from high-quality brass material: Fabricated from high‑grade brass and formed via precision hot forging process, it delivers outstanding strength and corrosion‑resistant performance. The nickel‑plated surface provides additional anti‑oxidation and wear‑resistance protection, ensuring long‑term durability under harsh water‑system operating conditions. It is available in two connection sizes, DN25 and DN32, to meet the requirements of standard piping dimensions.

2.Integrated Air Release, Drainage, and Sewage Discharge Functions: This 3-in-1 valve assembly consolidates three essential pipeline functions into a single compact unit: air exhaust valve for removing trapped air, drain valve for system maintenance, and sewage discharge valve for waste water evacuation. The multi-functional pipe air release valve design eliminates the need for multiple separate components, saving installation space and reducing potential leak points.

3.Optimized Air Release Chamber for Superior Efficiency: The precisely designed air‑vent chamber enables rapid and efficient discharge of accumulated air. This air discharge valve configuration ensures stable pressure maintenance and prevents cavitation damage, noise, and flow disruption in residential, commercial, and industrial water circulation systems.

4.Double-Locking Cover Design for Easy Installation: Engineered for user convenience, the quick-release cover employs a dual-locking mechanism that allows tool-free access for inspection and maintenance. This easy-install valve cover design significantly reduces service time and simplifies routine system checks, making it ideal for applications where frequent access may be required.

5.The conical O‑ring prevents connection wear and ensures reliable sealing: fitted with a conical O‑ring seal manufactured from high‑performance material. This dedicated seal design effectively mitigates frictional wear at joints and maintains zero‑leakage sealing performance across the full operating pressure range.

• Heating System High/Low Points

Installation: At the highest point of the heating circuit (air release) and the lowest point (drain/blowdown).
Value: One assembly at the system low point provides both sediment flushing and system draining; the air vent is typically at the high point. For compact systems, this assembly can be installed at a strategic mid‑point with access to both air and sediment removal.

• Boiler Room Headers

Installation: On the main supply or return header near the boiler.
Value: The assembly provides boiler system maintenance access-air purging, system draining, and sediment flushing-all from one connection point.

• Manifold Supply Lines

Installation: At the manifold inlet or outlet.
Value: The assembly allows individual manifold circuits to be purged of air and flushed of sediment without draining the entire heating system.

• Chilled Water Systems

Installation: At the highest and lowest points of chilled water loops.
Value: Air venting prevents air binding in cooling coils; drain and blowdown allow seasonal maintenance.

• Solar Thermal Systems

Installation: At the collector array high point and storage tank low point.
Value: The combination assembly addresses the unique challenges of solar thermal systems-air accumulation in collectors and sediment in storage tanks.

• Industrial Process Water

Installation: On process water supply and return lines.
Value: One component provides all three maintenance functions for industrial fluid loops.

• Location Selection

Air release – Install at the highest point of the system (or at a point where air naturally collects).

Drain and blowdown – Install at the lowest point of the system (or at a point where sediment can settle).

The assembly can be installed at a strategic point that balances both functions.

• Installation Steps

Choose the installation point – Select a location that serves both air venting and drain/blowdown needs.

Prepare the pipe – Install a tee at the selected point.

Apply PTFE tape – Wrap 3‑5 turns clockwise on the male thread.

Thread the assembly – Thread the assembly onto the pipe tee.

Position the assembly – Orient the unit so that:

The air vent is at the top (vertical)

The drain valve handle is accessible

The blowdown port is at the bottom

Tighten – Use a wrench on the body flats. Do not overtighten.

Test – Pressurize and check for leakage.

• Important Installation Notes

Vertical orientation – The air release chamber must be vertical for the float to operate correctly.

Access clearance – Ensure clearance above the air vent for servicing, and below the blowdown port for drainage.

Isolation valve – Install an isolation valve upstream so the assembly can be serviced without draining the entire system.

Proper routine maintenance extends service life and preserves sealing performance of this union air release valve assembly. Please follow below steps:

1. Surface & Internal Cleaning Wipe outer valve surface with soft cloth to remove dirt and impurities. Periodically open the cover and clear debris and sediment accumulated inside the valve cavity.
2. Lubrication for Moving Parts Apply suitable lubricant to movable components to lower friction and reduce mechanical wear.
3. Tighten Loose Fittings Inspect threaded joints and fasteners with proper tools. Retighten any loose parts to keep stable valve operation.
4. Replace Worn‑out Spare Parts Regularly inspect consumable parts including O‑ring seals and packing gaskets. Replace worn components in time to avoid leakage and malfunction.
5. Anti‑corrosion Protection Carry out anti‑corrosion protection for parts exposed to corrosive environment. You may apply anti‑corrosion coating or ensure compatible corrosion‑resistant auxiliary materials during installation.