Radiator Air Release Valve Assembly

Ordinary single-body radiator automatic air vent：Single float exhaust head only; does not include a base shut-off valve; to replace the exhaust valve, the radiator's inlet and outlet must be closed and the internal water drained; the system must be depressurized before disassembly is permitted; must be installed vertically; in the event of a leakage fault, the unit must be shut down for repair; simple structure and low cost.

Radiator air release valve assembly：Integrated 2-in-1 design: features a built-in brass isolation shut-off base and a float-type automatic exhaust valve head. The closed base incorporates an internal shut-off valve, allowing the system to operate under pressure without requiring the radiator to be drained; the exhaust valve head can then be directly unscrewed for cleaning, maintenance, or replacement, provided that the exhaust head remains oriented vertically upward. This design combines the advantages of exhaust functionality with online maintainability, while offering higher cost compared to standalone exhaust valves.

Yuanlun radiator air release valve assembly is combined float-type automatic air vent assembly for closed-loop radiator heating hydronic systems. Consists of two core parts：brass shut-off isolation base valve and removable float-type air vent head with EPDM sealing components.

PN16 nominal pressure-rating, working-temperature 5℃-90℃. Under normal operation, float-type vent head automatically releases air accumulated inside radiator;when air is exhausted and water fills vent cavity, buoyancy lifts float to close exhaust hole to prevent water spraying. Built-in base shut-off valve provides isolation function：after closing base valve, technicians can dismount, clean or replace vent head without draining radiator or depressurizing whole local heating circuit.

Critical functional limitation：

1. Vent head MUST be kept strictly vertical-upward during installation;tilted or horizontal mounting will break float buoyancy balance, lead to persistent dripping or complete loss of venting function.
2. This product ONLY discharges entrapped air. It is NOT safety relief valve and cannot provide over-pressure protection. System over-pressure hazard requires independent safety pressure relief valve.
3. Standard EPDM-seal brass variant applies for clean closed-loop heating water / glycol-mixed anti-freeze liquid. FORBIDDEN for steam medium. Rust, sand and solid impurities will easily block tiny exhaust hole and jam float assembly, resulting in continuous water-leakage; dirty-medium systems need upstream filter.

Suitable for residential apartments, office-hotel commercial radiator closed-loop heating systems, especially radiators where draining water for maintenance is inconvenient.

Important note: Installation recommended to be completed by qualified HVAC plumbing technicians. Keep vent head vertical upward at all times during mounting and later-period service.

• Integrated Shut-off Base-Valve Design: Unique combined assembly of isolation base valve plus float-type vent head. Close base valve to realize local isolation; vent-head can be disassembled, cleaned or replaced under system pressure without draining radiator, greatly reduces maintenance workload.
• Float-Driven Automatic Venting Function: Float-type mechanism automatically exhaust accumulated air inside radiator; after air is fully discharged, float rises with water-level to shut exhaust hole and avoid water leakage, no frequent manual bleeding operation required.
• Compact Radiator-Mount Layout: Optimized compact dimension, perfectly fits standard radiator top air-vent mounting interface DN15-DN25.
• Stable Hydronic-System Compatibility: PN16 pressure-rating, 5-90℃ working range, adapts for water / glycol-mixed anti-freeze closed-loop radiator heating circuits.

Important limitation：Not a pressure-relief safety valve;vent-head must strictly vertical-upward;steam medium prohibited; solid impurities will clog exhaust hole / float assembly.

Specifications

• Main Components & Function

• Operating Principle

Radiator air release valve assembly combines isolation base valve and float-type automatic air vent：

1. Normal venting working state: Base-valve fully open, vent-head strictly vertical-upward. Air separated from heating-water accumulates at radiator top and enters vent-head inner cavity. Air occupies cavity, water-level inside vent-head drops; float sinks by gravity, tiny exhaust orifice opens, entrapped air discharges to atmosphere.
2. Auto-close after air exhausted: After all entrapped air is vented, hot-water fills vent-head cavity. Water buoyancy lifts float assembly upwards; float blocks exhaust orifice tightly to stop water from spraying outside, realize automatic air-vent & water-shut-off cycle.
3. Maintenance service mode: When vent-head is clogged / malfunctioning, manually close built-in base-valve shut-off position. This isolates vent-head from radiator internal water volume. Now technicians can directly unscrew vent-head, perform cleaning float / exhaust-hole or replace whole vent-head. Radiator remains filled with water, no need to drain radiator or depressurize whole heating circuit. After service finished, screw vent-head back on and reopen base-valve to resume normal vent function.

Three critical operating reminders：

1. Vent-head must keep strictly vertical-upward. If tilted or installed horizontally, float cannot work under normal buoyancy balance; symptom: continuous dripping water or completely unable to exhaust air.
2. This assembly only exhaust air, CANNOT serve as over-pressure safety relief valve. If system over-pressure risk exists, must install independent safety pressure relief valve on boiler / manifold.
3. Tiny exhaust orifice and float gap are very sensitive to rust, sand, scale particles. Solid impurities jam exhaust hole or lock float → permanent dripping leakage. Dirty-medium heating-system must install upstream filter-strainer.
4. Steam is strictly forbidden for standard EPDM-seal brass model.

• Residential Radiator Closed-Loop Heating Systems

Use-case: Automatic air vent for radiator top mounting point, especially radiators which are difficult to drain water during maintenance. Project value: Thanks to isolation base-valve, vent-head can be cleaned / replaced without draining radiator water, reduces household maintenance disturbance.

• Commercial Office / Hotel Centralized Radiator Heating Projects

Use-case: Large quantity radiators in commercial buildings; frequent routine HVAC maintenance requirements. Project value: Online service capability reduces system shutdown duration; avoid large-scale water draining work for hundreds of radiators.

• Retrofit Renovation Heating-System Projects

Use-case: Renovate old heating circuits; replace old single-body air vents with this assembly for easier later-period service. Project value: Retrofit onto existing standard DN15-DN25 radiator vent port without large-scale pipe modification.

Application exclusion:

1. Not for steam pipeline system.
2. Cannot replace safety pressure-relief valve for over-pressure protection.
3. Medium carrying large amount rust/sand solid particles must add upstream filter-strainer, otherwise vent-head will quickly clog and leak.

• Pre-Installation Check

1. Confirm assembly DN-size matches radiator top air-vent mounting port thread specification.
2. Inspect brass base-valve, removable vent-head, float assembly and EPDM O-ring seals; reject cracked, deformed, float-jammed components.
3. Confirm installation layout requirement: vent-head must point strictly vertically upward after mounting; tilt or horizontal orientation is prohibited.
4. Clean radiator mounting-thread, remove burr, rust debris; prepare qualified PTFE-tape.
5. Dirty-medium project: confirm upstream filter-strainer is configured to protect vent-head exhaust orifice and float.

• Installation Steps

1. Wind PTFE-tape 3-5 clockwise-turns on radiator top mounting thread port.
2. Screw the isolation base-valve onto radiator top port; apply wrench torque only on base-valve brass hex flats. Do NOT apply wrench force onto plastic float vent-head.
3. Adjust base-valve final position to guarantee vent-head mounting interface points strictly vertically upward.
4. Screw float-type vent-head hand-tight onto base-valve output interface; check EPDM O-ring is correctly seated between mating faces.
5. Keep base-valve in fully-open working position after assembly finished.
6. Fill radiator and whole heating-system with water, perform pressure-testing.
7. Observe vent-head: air will automatically exhaust; after air is discharged vent-head stops dripping water. Inspect thread-joint and O-ring mating-face for external leakage.

• Important Installation Notes

1. Installation recommended for qualified HVAC plumbing technicians.
2. Vent-head must strictly vertical upward after installation; tilt / horizontal mounting will cause float malfunction, water dripping or no venting.
3. Wrench only on brass base-valve hex flats; never apply wrench force on vent-head plastic housing to avoid internal float damage.
4. Base-valve is only for maintenance isolation; normal running keep base-valve fully open. Do NOT close base-valve during daily heating operation (air cannot vent).
5. Dirty-medium must configure upstream filter-strainer to block rust/sand particles protecting exhaust orifice and float assembly.
6. This product is air-vent only; add independent safety relief valve for system over-pressure protection.
7. Standard variant not suitable for steam medium.

Routine-Maintenance Suggestion

• Visual inspection for joint leakage & abnormal vent-head dripping: Quarterly during heating-season
• System annual overhaul: Close base-valve, take-down vent-head, clean exhaust-orifice and float assembly, inspect EPDM O-ring ageing condition: Annually before heating-season startup
• Replace clogged / damaged vent-head or aged O-ring spare-parts upon dripping / vent-failure: As-required
• Dirty-medium circuit: Periodically clean upstream filter-strainer to reduce impurity entering vent assembly.

When purchasing radiator air release valve assembly：confirm DN-size DN15-DN25 thread matches radiator top vent port. Clarify project requirement：

This is isolation-base + vent-head combined assembly, allows online vent-head service without radiator draining. If no maintenance-convenience requirement, cheaper single-body radiator air vent is alternative option.

Hard requirement: vent-head must install strictly vertical-upward; confirm radiator mounting port geometry can achieve vertical-up orientation after base-valve mounting.

Functional boundary: Only air-vent, cannot replace safety pressure-relief valve for over-pressure protection.

Medium: clean water/glycol closed-loop heating system; steam, strong-corrosion prohibited; dirty-medium must match upstream filter-strainer.

Yuanlun radiator air release valve assembly is PN16 float-type combined air-vent assembly for radiator closed-loop heating-systems, DN15-DN25 size-range. Integrated brass isolation shut-off base-valve and removable float-type vent-head. After closing base-valve, vent-head can be cleaned / replaced under system pressure without draining radiator water, greatly simplifies later-period HVAC maintenance. Vent-head must be installed strictly vertically upward; automatically exhaust entrapped air inside radiator and auto-close exhaust hole to stop water leakage.

Functional boundary：Only air-discharge function, NOT safety pressure-relief valve; tilted / horizontal mounting will cause failure; standard model not for steam; solid impurities easily clog exhaust orifice and float assembly. Standard variant applies for clean 5-90℃ water / glycol-mixed anti-freeze closed-loop radiator heating circuits. Widely-applied in residential apartments, office-hotel commercial centralized radiator heating and heating-system renovation projects. Sample-order supported for pre-project-evaluation, 15-day standard lead-time for worldwide plumbing-HVAC distributors and engineering-contractors.

Zhejiang Yuanlun Valve Co., Ltd. was founded in 2006, formerly known as Yuhuan Guohong Valve Co., Ltd. It is located in Yuhuan, Zhejiang Province, known as the "Valve Capital of China". After nearly two decades of stable development, Yuanlun Valve is a professional manufacturer for HVAC valves integrating R&D, production and sales. Our product portfolio covers floor heating systems, air-conditioning systems, domestic water valves, including ball valves, thermostatic valves, manifolds, check valves, stop valves, filter valves, angle valves, pipe fittings, corrugated pipes and other series.