Vent Drain Valve | Automatic Air Vent & Liquid Drain | DN10–50 | 10 bar | CE/ISO

Vent Drain Valve - dual-function compact air venting + liquid draining. High points remove trapped air/non-condensable gases; low points discharge condensate/sediment - prevents airlock, blockage, water hammer. Automatic (gravity/pressure, no power, unattended) or manual (handwheel, precise). Precision core + PTFE/EPDM seals - tight shut-off, zero leakage. Body: nickel-plated brass, SS304/316, PVC, PE, GRP - indoor HVAC to outdoor/marine. Compact, light, threaded/flanged/quick-connect, easy install. DN10–50, 10 bar, -10~100°C. CE/ISO; FDA optional. For water, steam, inert gas, wastewater, chemicals. Cost-effective pipeline management. China factory, 18mo warranty, OEM/ODM.

1. Dual-Function Integration - Air Vent + Liquid Drain: Combines ventilation and drainage in one compact valve body - eliminating the need for separate air vents and drain valves. Installed at pipeline high points to vent trapped air/non-condensable gases (preventing airlock, pressure imbalance, and corrosion) and at low points to drain condensate/sediment (preventing blockage, water hammer, and freeze damage). This dual-function design reduces installation cost, space, and maintenance points - one valve does the job of two. The integrated design also means fewer potential leak points in the piping system. For systems requiring both air venting at high points and draining at low points, specifying a single valve type simplifies procurement, spare parts inventory, and maintenance training. The valve body is designed to handle both functions - the float/gravity mechanism responds to either air accumulation (high point) or liquid accumulation (low point) depending on installation orientation.

2. Automatic or Manual Operation: Two operation modes available. Automatic type: opens and closes by gravity or pressure differential - no external power or manual intervention required, ideal for continuous unattended operation. The automatic mechanism (float-operated or gravity-operated) responds to changes in liquid level or pressure - opening when air/liquid accumulates and closing automatically when cleared. This makes it suitable for remote locations, hazardous areas, and systems where continuous venting/draining is needed without operator attention. Manual type: handwheel or lever operated for precise control in scenarios requiring scheduled draining, maintenance, system startup/shutdown venting, or specific flow management. The manual type gives operators positive control over the vent/drain port. Both types provide reliable, repeatable performance and use the same precision valve core and seal technology. Automatic valves are typically installed vertically (recommended) for proper float operation; manual valves can be installed horizontally or vertically.

3. Stable & Leak-Proof Sealing: Adopts high-quality sealing materials - PTFE for chemical/high-temperature resistance, EPDM for water/steam service (NBR, FKM/Viton optional) - and a precision-machined valve core design - ensuring tight sealing with zero leakage under working pressure up to 10 bar. The seal is resistant to aging, corrosion, and thermal cycling, adapting to long-term stable operation in harsh environments. The valve core is precision-machined brass or stainless steel with a replaceable seal - when the seal eventually wears, it can be replaced without replacing the entire valve core or body, reducing maintenance cost. The seal geometry is designed to provide positive shut-off in both automatic (float-actuated) and manual (handwheel-actuated) modes. For food-grade service, FDA-certified EPDM/PTFE seals are available. The deep seal engagement ensures that even minor wear does not cause leakage - extending the interval between seal replacements.

4. Multiple Material Options for All Environments: Valve body available in nickel-plated brass (CW614N) for general plumbing/HVAC (good machinability, cost-effective, corrosion resistance with nickel plating), stainless steel 304/316 for corrosive/food-grade service (SS316 for chloride/seawater/food), PVC/PE for chemical/wastewater (lightweight, excellent chemical resistance, low cost), and GRP (glass-reinforced plastic) for marine/outdoor UV-resistant applications (excellent weatherability, saltwater resistance, high strength-to-weight). Each material is selected for specific media and environmental requirements, ensuring long service life. The wide material range makes the valve suitable for everything from indoor potable water systems to outdoor marine piping to corrosive industrial waste. Material test reports (MTR) are provided for all metal bodies; 3.2 certificates with third-party verification are optional. For food/pharma, SS316 with FDA-certified seals and clean-room assembly is available.

5. Easy Installation & Maintenance: Compact structure, lightweight design, and multiple connection methods - threaded (G thread per ISO 228 or NPT per ASME B1.20.1, sizes 1/8", 1/4", 3/8", 1/2"), flanged (PN10/PN16 per EN 1092-1, ANSI Class 150 per ASME B16.5, GB/T 9113), or quick-connect (push-fit or compression) - compatible with most piping systems. Threaded ends are gauged for proper fit and leak-free installation. The valve core is easily accessible for cleaning or replacement without removing the entire valve from the pipeline - reducing maintenance workload and downtime cost. The replaceable seal and valve core design means routine maintenance (seal replacement, core cleaning) can be done quickly with basic tools. For automatic types, the float mechanism is accessible for inspection/cleaning (important for sediment-laden fluids). The compact size and light weight make installation easy for one person, especially in tight spaces like radiator cabinets, equipment skids, and ceiling plenums.

6. Wide Pressure & Temperature Adaptability: Maximum working pressure up to 10 bar (145 psi), working temperature range -10°C to 100°C (14°F to 212°F, per material & seal). EPDM seals are suitable for water/steam up to 100°C; PTFE seals for chemical service up to 100°C; NBR for general water/oil; FKM (Viton) for higher temperature/chemical resistance (optional). Suitable for various media including water, steam, inert gas, wastewater, mild chemicals, condensate, and sediment-laden fluid - strong versatility across HVAC, industrial, plumbing, marine, and food/pharma applications. The pressure and temperature range covers most building services and light industrial applications. For higher pressure (>10 bar) or higher temperature (>100°C), or for flammable/explosive/toxic media, the forged steel globe valve range is recommended (this vent drain valve is not suitable for those services). The automatic float mechanism is calibrated for consistent opening/closing pressure within the rated range, verified by cycle testing (≥5,000 cycles).

Vent Drain Valve: gravity or manual + precision seal. Auto Air Vent (high): trapped air drops level → float lowers → opens vent → air released; liquid rises, float lifts → closes vent; cycle repeats. Auto Drain (low): condensate accumulates → level rises → float opens drain → discharges; level drops → closes, no gas loss. Manual: handwheel lifts/lowers core → opens/closes on demand. PTFE/EPDM seal zero leakage. Auto needs no power - remote OK. DN10–50, 10 bar, -10~100°C. Vertical auto, horizontal manual.

HVAC & Heating Systems: Used in radiators, central air conditioning systems, boilers, and heating pipelines to discharge trapped air and condensed water - ensuring efficient heat exchange, preventing airlock and cold spots, and maintaining stable system operation and energy efficiency. Automatic air vents at high points (radiator tops, boiler uppers, pipeline risers) continuously remove air that reduces heat transfer efficiency and causes noise; drain valves at low points (boiler bottoms, coil drains, pipeline low spots) remove condensate and sediment. The automatic type operates unattended, maintaining system efficiency without operator intervention. The compact size fits radiator cabinets and ceiling plenums. Nickel-plated brass or SS304 bodies suit HVAC water chemistry; EPDM seals handle hot water/steam up to 100°C. Proper air venting improves heating system efficiency by 5–15% by eliminating airlock and ensuring full water fill.

Industrial Pipeline Systems: Applied in chemical, petroleum, power, metallurgy, and manufacturing industries - installed on circulating water systems, steam pipelines, cooling towers, and reaction equipment to remove air pockets and fluid accumulation, prevent pipeline corrosion and blockage, and protect equipment safety. Air pockets in industrial piping cause flow instability, pump cavitation, and corrosion (oxygen pitting); condensate accumulation causes water hammer and reduced flow cross-section. SS316 bodies handle corrosive industrial fluids; PVC/PE for chemical waste lines; GRP for outdoor/cooling tower service. The automatic type is ideal for remote pipeline high/low points where regular operator access is difficult. The manual type is used at equipment drains and sampling points where positive control is needed. PTFE seals handle mild chemical exposure. For high-pressure/high-temperature industrial service (>10 bar/>100°C), use forged steel globe valves.

Plumbing & Drainage + Agricultural Irrigation:Plumbing & Drainage: Used in residential and commercial building water supply, drainage systems, and sewage treatment plants - to balance pipeline pressure, discharge harmful gases (methane, hydrogen sulfide), and drain accumulated fluid, ensuring smooth drainage, preventing backflow and odor leakage. Air admittance/vent valves at drainage high points prevent sewer gas from entering buildings; drain valves at low points remove sediment. Agricultural Irrigation: PVC/PE and brass models used in agricultural irrigation, greenhouse systems, and water treatment - for air venting and drain-down in seasonal pipelines, preventing freeze damage and maintaining efficient water distribution. Seasonal drain-down is critical in cold climates to prevent pipe freeze/burst. The automatic type vents air during irrigation startup (preventing airlock in drip/sprinkler systems) and drains at shutdown. PVC/PE bodies are lightweight and corrosion-resistant for outdoor agricultural use.

Marine & Outdoor Applications: GRP and stainless steel (316) models suitable for shipboard piping, offshore platforms, and outdoor installations - with excellent UV resistance, saltwater corrosion resistance, and weatherproof performance for harsh outdoor and marine environments. GRP (glass-reinforced plastic) bodies are inherently corrosion-resistant to saltwater and UV, requiring no painting or coating; SS316 provides pitting resistance in chloride-rich marine atmospheres. On ships, vent drain valves are used on ballast water, cooling water, and bilge systems - high-point vents prevent airlock in seawater cooling lines; low-point drains remove bilge water and sediment. The automatic type operates without power, suitable for shipboard locations where electrical power may be limited or hazardous. Quick-connect or threaded connections facilitate installation in tight engine room spaces. UV resistance prevents material degradation from prolonged sun exposure on offshore platforms and exterior piping.

Food & Pharmaceutical Industry: Food-grade stainless steel (316) and FDA-certified EPDM/PTFE seal materials available - suitable for food processing, beverage, brewery, and pharmaceutical production pipelines, ensuring hygienic safety and compliance with food-contact regulations. Food-grade valves are assembled in clean-room conditions, internally cleaned and capped to prevent contamination. SS316 body provides corrosion resistance and cleanability (pickled and passivated surface); FDA-certified EPDM/PTFE seals meet food-contact requirements. In breweries and beverage plants, automatic air vents at tank and pipeline high points prevent oxidation and CO2 loss; drain valves at low points remove CIP (clean-in-place) rinse water and product residue. In pharmaceutical production, vent/drain valves maintain sterile boundary integrity and facilitate SIP (steam-in-place) condensate removal. The precision seal ensures zero leakage - critical for preventing contamination ingress or product loss. Material traceability (MTR, 3.2 cert) supports regulatory compliance (FDA, GMP).

Every Vent Drain Valve: Material cert - brass EN12164, SS ASTM, MTR. Seal - PTFE/EPDM certified, tested per ISO7619/ASTM D2000. Pressure - 100% shell 1.5×, seat 1.1×, no leakage. Functional - automatic cycle test min 5,000 cycles, verify float mechanism + consistent pressure. Thread - gauged ISO 228/ASME B1.20.1, proper fit. Surface - nickel-plated brass salt spray ISO 9227; SS pickled/passivated. Cleanliness - food-grade clean-room, cleaned/capped. Marking - permanent material/size/pressure/direction. Packaging - end caps, bubble wrap, cartons; food-grade sealed. CE/ISO 9001; FDA optional. Batch traceable. 18mo warranty.

Q1: What is a vent drain valve, and what is the difference between automatic and manual types? 

A: A vent drain valve (also called ventilation and drainage integrated valve) is a dual-function compact valve that combines air venting and liquid draining in one unit - eliminating the need for separate air vents and drain valves. It is installed at pipeline high points to remove trapped air/non-condensable gases (preventing airlock, pressure imbalance, corrosion) and at low points to discharge condensate/sediment (preventing blockage, water hammer, freeze damage). Two operation types: (1) Automatic type: opens and closes by gravity or pressure differential (float-operated or gravity-operated mechanism) - no external power or manual intervention required. When air accumulates (high point), the liquid level drops, the float lowers, and the vent port opens to release air; once air is expelled, liquid rises, the float lifts, and the vent closes automatically (no liquid discharge). When condensate accumulates (low point), the level rises, the float/pressure mechanism opens the drain port; when level drops, it closes automatically (no gas/product loss). Ideal for continuous unattended operation - remote locations, hazardous areas, systems needing continuous venting/draining. (2) Manual type: operated by handwheel or lever - the operator manually lifts/lowers the valve core to open/close the vent/drain port on demand. Provides precise control for scheduled maintenance, system startup/shutdown venting, or specific flow management. Suitable where positive operator control is needed (equipment drains, sampling points, seasonal drain-down). Both types use the same precision valve core with PTFE/EPDM seals for zero leakage, and are available in the same sizes/materials/connections. Choose automatic for continuous, unattended venting/draining at remote or hard-to-access points. Choose manual for scheduled maintenance, startup/shutdown, or where operator control and positive shut-off are required. Automatic types are typically installed vertically (recommended for proper float operation); manual types can be horizontal or vertical. Both types are compact, lightweight, and easy to install/maintain.

Q2: Where should a vent drain valve be installed - high point vs low point?

A: Installation position depends on the function: (1) For air venting (high-point installation): Install at the highest point of a pipeline or system where air naturally accumulates - radiator tops, boiler uppers, pipeline riser crests, tank top connections, pump discharge high points, ceiling piping peaks. Trapped air reduces heat transfer efficiency (HVAC), causes pump cavitation and flow instability (industrial), creates pressure imbalance, and accelerates corrosion (oxygen pitting). The automatic float mechanism responds to air accumulation: as air collects, the liquid level in the valve body drops, the float lowers, and the vent port opens to release air to atmosphere; once air is expelled, liquid rises, the float lifts, and the vent closes - preventing liquid discharge. (2) For liquid draining (low-point installation): Install at the lowest point - drip legs, sumps, bottom of equipment/tanks, pipeline low spots, boiler bottoms, coil drains. Condensate, sediment, and accumulated liquids collect at low points, causing blockage, water hammer, reduced flow cross-section, and freeze damage in cold climates. The automatic mechanism responds to liquid accumulation: as condensate collects, the level rises to a threshold, the float/pressure-differential mechanism opens the drain port to discharge liquid; when the level drops, it closes automatically - preventing gas or product loss. (3) Dual-function use: Some installations use separate valves for each function; our dual-function valve can serve both purposes when properly positioned - but a single valve is typically dedicated to either venting (high) or draining (low), as the float mechanism is calibrated for one function. (4) Orientation: Automatic types - vertical installation recommended for proper float operation (float moves vertically with liquid level). Manual types - horizontal or vertical. (5) Accessibility: Install where the valve is accessible for maintenance (seal replacement, float cleaning, core inspection), especially for sediment-laden fluids where the float mechanism may need periodic cleaning. (6) Isolation: For critical systems, install an isolation valve upstream of the vent/drain valve to allow servicing without shutting down the entire system. Always follow the manufacturer's installation manual for specific orientation and spacing requirements.

Q3: What materials are available, and which should I choose for my medium/environment?

A: Five body material options, each suited to specific media and environments: (1) Nickel-plated brass (CW614N): General plumbing/HVAC - good machinability, cost-effective, nickel plating provides corrosion resistance. Suitable for water, steam (≤100°C), inert gas, indoor HVAC/radiator/boiler service. Not for highly corrosive or saltwater environments. (2) Stainless steel 304 (SS304): Mild corrosive/industrial - good corrosion resistance to water, steam, mild chemicals, food-grade service. Suitable for food processing, beverage, pharmaceutical, general industrial. (3) Stainless steel 316 (SS316): Seawater, food-grade, strong corrosive - molybdenum addition provides pitting resistance in chloride environments. Suitable for marine (saltwater), offshore, food/pharma (FDA), chemical processing with chlorides, brewery/dairy. (4) PVC/PE: Chemical/wastewater - lightweight, excellent chemical resistance (acids, alkalis, salts), low cost, easy to install. Suitable for chemical waste lines, sewage treatment, agricultural irrigation, water treatment. Temperature limited to ~60°C for PVC (check specific rating). Not for high pressure or high temperature. (5) GRP (glass-reinforced plastic): Marine/outdoor UV-resistant - excellent weatherability, saltwater corrosion resistance, UV stability, high strength-to-weight. Suitable for shipboard piping, offshore platforms, outdoor installations, cooling towers. Seal materials: PTFE (chemical/high-temp resistance, food-grade FDA option), EPDM (water/steam ≤100°C, food-grade FDA option), NBR (general water/oil, optional), FKM/Viton (higher temp/chemical resistance, optional). Selection guide: (a) Indoor HVAC/radiator/water → nickel-plated brass + EPDM. (b) Food/beverage/pharma → SS316 + FDA EPDM/PTFE, clean-room assembly. (c) Marine/offshore/saltwater → SS316 or GRP + EPDM/PTFE. (d) Chemical waste/sewage → PVC/PE + PTFE. (e) Outdoor/UV exposure → GRP or SS316. (f) Steam (≤100°C) → SS304/316 or brass + EPDM. Always verify material compatibility with your specific medium, concentration, temperature, and pressure. Contact our engineers for material selection guidance. Material test reports (MTR) provided for metal bodies; 3.2 certificates with third-party verification optional.

Q4: What are the pressure, temperature, size, and connection specifications?

A: Sizes: DN10 – DN50 (3/8" – 2"); custom sizes available on request. Maximum working pressure: 10 bar (145 psi). Working temperature: -10°C to 100°C (14°F to 212°F), depending on body material and seal type. EPDM seals suitable for water/steam up to 100°C; PTFE seals for chemical service up to 100°C; NBR for general water/oil; FKM (Viton) optional for higher temperature/chemical. Connections: (a) Threaded: G thread (ISO 228) or NPT (ASME B1.20.1), standard sizes 1/8", 1/4", 3/8", 1/2" - gauged for proper fit and leak-free installation. (b) Flanged: PN10/PN16 (EN 1092-1), ANSI Class 150 (ASME B16.5), GB/T 9113. (c) Quick-connect: push-fit or compression fittings. Custom connections available on request. Flow direction: Unidirectional (marked on body); bidirectional available on request. Installation position: High-point (air vent) or low-point (liquid drain). Installation orientation: Vertical (recommended for automatic type for proper float operation); horizontal for manual type. Applicable medium: Water, steam, inert gas, wastewater, mild chemicals, condensate, sediment-laden fluid. NOT suitable for: Flammable/explosive media, toxic media, high-pressure (>10 bar), high-temperature (>100°C) - use forged steel valves for these services. Testing: Shell hydrostatic test 1.5× rated pressure (15 bar); seat leak test 1.1× rated pressure (11 bar); gas seal test 0.6 MPa; automatic cycle life ≥5,000 open-close cycles. Certification: CE, ISO 9001:2015; FDA optional for food-grade SS316 models. Surface treatment: Nickel-plated (brass), pickled & passivated (stainless steel), as-molded (PVC/PE/GRP). Material traceability: Material test reports included; 3.2 with third-party verification optional. MOQ: 1 piece (sample order accepted). Lead time: Standard 15–30 days; custom 30–45 days. Warranty: 18 months from shipment or 12 months from installation, whichever first. HS Code: 8481804090. The pressure/temperature range covers most building services and light industrial applications. For higher pressure/temperature or hazardous media, consider our forged steel globe valve range (API 602, Class 150–2500, -29~425°C).

Q5: What is the lead time, warranty, certification, and MOQ?

A: Lead Time: Standard valves (common sizes/materials/connections in stock or regular production): 15–30 days from order. Custom materials, connections, sizes, or special configurations (bidirectional, special seals, custom marking): 30–45 days. Sample orders (1–5 pcs): typically 7–15 days depending on stock. Rush orders may be accommodated - contact our sales team. Warranty: 18 months from shipment or 12 months from installation, whichever comes first. Warranty covers manufacturing defects in materials and workmanship under normal use and proper installation per our guidelines. Consumable parts (seals, float mechanism) are covered for 12 months. Warranty does not cover damage from improper installation, misuse, media incompatibility, exceeding pressure/temperature ratings, or normal wear. For warranty claims, provide valve serial number, purchase order, photos, and failure description; we will repair or replace defective valves. Certification: Standard - CE (European conformity), ISO 9001:2015 (quality management system). Optional - FDA certification for food-grade SS316 models (FDA-certified EPDM/PTFE seals, clean-room assembly, material traceability). Third-party inspection (BV, SGS, DNV, ABS) available on request at additional cost. Material test reports (MTR/EN 10204 3.1) included with metal valves; 3.2 certificates with third-party verification optional. MOQ (Minimum Order Quantity): 1 piece - sample orders accepted for evaluation. For OEM/ODM custom branding/packaging, minimum quantities may apply (typically 50–100 pcs depending on customization level). Payment Terms: T/T 30% deposit, 70% before shipment; L/C at sight for large orders. Packaging: Valves protected with end caps, bubble wrap, and export cartons; food-grade valves individually sealed; custom packaging (wooden crates, labeled cartons, OEM branding) available. Shipping: FOB Shanghai/Ningbo, or CIF/DDP as requested. We support both small sample shipments (express/courier) and full container loads (sea freight). OEM/ODM: We offer OEM (your brand labeling/packaging) and ODM (custom design/configuration) services - custom body marking, private label, custom connections, special materials, custom packaging. Our engineering team can collaborate on custom valve designs for specific applications. After-sales: Technical support for installation, operation, maintenance; spare parts (seals, valve cores, floats) available; valve sizing and material selection assistance from our engineers. Contact us with your application details (medium, pressure, temperature, size, connection, quantity) for a formal quotation and lead time confirmation.

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