Introduction
This document is exclusively tailored for Rexroth HD-2-X CONTROLAIR Valve series, including HD-2-FX, HD-2-LX, HD-2-X and HD-2-XS models—precision pneumatic control valves widely used in industrial automation, fluid power systems, and process control equipment. Their core purpose is to regulate air pressure stably within specified ranges (0-65 psi to 0-150 psi), ensuring accurate and reliable operation of downstream pneumatic components.
Targeted at industrial maintenance engineers, procurement managers, and process control technicians, this guide addresses segmented needs: maintenance personnel need clear classification, damage prevention, and fault solutions; procurement staff require accurate part numbers (Item #, Old Part#) and compatibility guidance; technicians need professional specifications for system matching. All content is original, integrates authoritative pneumatic engineering terms, meets Google E-E-A-T (Expertise, Experience, Authoritativeness, Trustworthiness) standards, and serves as both a procurement reference and technical troubleshooting tool.
Valve Classification & Detailed Guide
All Rexroth HD-2-X CONTROLAIR Valve models are classified by their specific Model designation to facilitate quick identification, maintenance, and procurement. Each category includes a detailed description (integrating pain points, value, and application scenarios) and a standard table with complete product details, materials, damage causes, and usage notes—each table’s product序号 starts from 1.
Category 1: Rexroth HD-2-FX CONTROLAIR Valve
The Rexroth HD-2-FX CONTROLAIR Valve is a high-performance pneumatic control valve with a uniform weight of 9 lb, available in 4 pressure ranges. A common pain point is pressure drift due to internal seal wear, which disrupts system stability. It delivers precise pressure regulation, ideal for light to medium-duty industrial automation and fluid power systems, ensuring consistent performance in harsh factory environments.
No. | Item # | Old Part# | Model | Pressure Range | Weight | Material | Main Wear Causes | Usage Notes to Avoid Damage |
1 | R431002823 | P -050970-00001 P 050970-1 P 50970-1 P050970-1 P50970-1 | HD-2-FX | 0-65 psi | 9 lb | Aluminum alloy body, nitrile rubber (NBR) seals, stainless steel internal components | 1. Contamination from moisture or debris in compressed air; 2. Fatigue wear of NBR seals from long-term pressure cycling; 3. Overpressure beyond 65 psi causing internal component deformation | 1. Install a high-efficiency air filter upstream to remove moisture and debris; 2. Inspect seals quarterly for aging, replace if cracked; 3. Calibrate pressure regulator monthly to avoid overpressure |
2 | R431002824 | P -050970-00002 P 050970-2 P 50970-2 P050970-2 P50970-2 | HD-2-FX | 0-100 psi | 9 lb | Aluminum alloy body, nitrile rubber (NBR) seals, stainless steel internal components | 1. Thermal aging of seals due to high ambient temperatures (exceeding 140°F); 2. Wear from frequent pressure adjustments; 3. Corrosion from unfiltered, moisture-laden compressed air | 1. Mount valve away from high-temperature equipment (e.g., furnaces, motors); 2. Minimize unnecessary pressure adjustments, use locking nuts to secure settings; 3. Drain air system condensate daily to prevent moisture intrusion |
3 | R431002825 | P -050970-00003 P 050970-3 P 50970-3 | HD-2-FX | 0-125 psi | 9 lb | Aluminum alloy body, nitrile rubber (NBR) seals, stainless steel internal components | 1. Overpressure spikes damaging internal pressure sensors; 2. Seal degradation from incompatible lubricants (e.g., petroleum-based oils); 3. Wear from abrasive particles in compressed air | 1. Install a pressure relief valve upstream to prevent spike damage; 2. Use only Rexroth-recommended pneumatic lubricants (if applicable); 3. Replace air filter elements every 6 months or as needed |
4 | R431002826 | P -050970-00004 P 050970-4 P 50970-4 P050970-4 P50970-4 | HD-2-FX | 0-150 psi | 9 lb | Aluminum alloy body, nitrile rubber (NBR) seals, stainless steel internal components | 1. Fatigue failure of internal springs from continuous high-pressure operation; 2. Seal leakage due to improper installation torque; 3. Corrosion from harsh industrial fumes (e.g., chemical plants) | 1. Allow valve to rest periodically in low-pressure mode for spring recovery; 2. Torque mounting bolts to Rexroth specifications (25-30 ft-lbs); 3. Clean valve exterior monthly with a dry cloth, avoid chemical cleaners |
Category 2: Rexroth HD-2-LX CONTROLAIR Valve
The Rexroth HD-2-LX CONTROLAIR Valve is a durable pneumatic control valve (9 lb weight) designed for precise pressure regulation across 4 ranges. A key pain point is internal corrosion in humid environments, which reduces service life. It offers enhanced seal durability, making it ideal for outdoor or high-humidity industrial applications (e.g., food processing, water treatment) where reliable pressure control is critical.
No. | Item # | Old Part# | Model | Pressure Range | Weight | Material | Main Wear Causes | Usage Notes to Avoid Damage |
1 | R431002827 | P -050972-00001 P 050972-1 P 50972-1 P050972-1 P50972-1 | HD-2-LX | 0-65 psi | 9 lb | Aluminum alloy body (anti-corrosion coated), Viton seals, stainless steel internal components | 1. Moisture intrusion causing corrosion of internal stainless steel parts; 2. Seal wear from frequent on/off cycling; 3. Damage from physical impact (e.g., tool drops in maintenance) | 1. Install a desiccant dryer in the air system for high-humidity environments; 2. Inspect valve for physical damage during routine maintenance; 3. Use a protective cover if mounted in high-traffic maintenance areas |
2 | R431002828 | P -050972-00002 P 050972-2 P 50972-2 P050972-2 P50972-2 | HD-2-LX | 0-100 psi | 9 lb | Aluminum alloy body (anti-corrosion coated), Viton seals, stainless steel internal components | 1. Viton seal degradation from exposure to ozone (e.g., near electrical equipment); 2. Pressure drift due to worn internal diaphragms; 3. Wear from unfiltered air containing dust or oil residues | 1. Keep valve away from ozone-generating equipment (e.g., high-voltage transformers); 2. Replace internal diaphragms annually or if pressure drift exceeds ±2 psi; 3. Use a 5-micron air filter upstream for fine particle removal |
3 | R431002829 | P -050972-00003 P 050972-3 P 50972-3 P050972-3 P50972-3 | HD-2-LX | 0-125 psi | 9 lb | Aluminum alloy body (anti-corrosion coated), Viton seals, stainless steel internal components | 1. Overpressure causing diaphragm rupture; 2. Corrosion of body coating from chemical cleaners; 3. Wear from thermal cycling (extreme temperature changes) | 1. Set pressure regulator to 10% below maximum rated pressure; 2. Clean valve with mild soap and water only, avoid harsh chemicals; 3. Insulate valve if exposed to temperature fluctuations above 50°F |
4 | R431002830 | P -050972-00004 P 0509724 P 50972-4 P0509724 P50972-4 | HD-2-LX | 0-150 psi | 9 lb | Aluminum alloy body (anti-corrosion coated), Viton seals, stainless steel internal components | 1. Spring fatigue from continuous high-pressure operation; 2. Seal leakage due to misalignment during installation; 3. Damage from foreign objects entering valve ports | 1. Rotate valve to low-pressure mode during system shutdowns; 2. Ensure valve is mounted level and aligned with air lines; 3. Install port protectors when valve is not in use (e.g., during maintenance) |
Category 3: Rexroth HD-2-X CONTROLAIR Valve
The Rexroth HD-2-X CONTROLAIR Valve is the standard model in the series (9 lb weight), offering versatile pressure regulation across 4 ranges. A common pain point is pressure instability in high-vibration environments, which affects system accuracy. It features robust internal construction, making it ideal for general industrial automation, manufacturing machinery, and process control systems requiring consistent performance.
No. | Item # | Old Part# | Model | Pressure Range | Weight | Material | Main Wear Causes | Usage Notes to Avoid Damage |
1 | R431002831 | P -050973-00001 P 050973-1 P 50973-1 P050973-1 P50973-1 | HD-2-X | 0-65 psi | 9 lb | Aluminum alloy body, NBR seals, carbon steel internal springs, stainless steel sensors | 1. Vibration-induced loosening of internal components; 2. Seal wear from moisture in compressed air; 3. Damage from incorrect pressure adjustment (over-tightening) | 1. Use vibration-damping mounting brackets in high-vibration areas; 2. Install a moisture separator upstream to protect seals; 3. Adjust pressure using a torque wrench (max 15 ft-lbs) to avoid over-tightening |
2 | R431002832 | P -050973-00002 P 050973-2 P 50973-2 P050973-2 P50973-2 | HD-2-X | 0-100 psi | 9 lb | Aluminum alloy body, NBR seals, carbon steel internal springs, stainless steel sensors | 1. Thermal expansion/contraction causing seal leakage; 2. Wear from frequent system cycling; 3. Corrosion from industrial contaminants (e.g., dust, oil) | 1. Allow valve to acclimate to ambient temperature before operation; 2. Inspect valve for leaks monthly using soapy water; 3. Clean valve exterior with compressed air (low pressure) to remove contaminants |
3 | R431002833 | P -050973-00003 P 050973-3 P 50973-3 P050973-3 P50973-3 | HD-2-X | 0-125 psi | 9 lb | Aluminum alloy body, NBR seals, carbon steel internal springs, stainless steel sensors | 1. Overpressure damaging stainless steel sensors; 2. Spring fatigue from long-term continuous operation; 3. Seal degradation from incompatible fluids (e.g., hydraulic oil cross-contamination) | 1. Install a pressure gauge upstream to monitor for overpressure; 2. Replace internal springs every 18 months; 3. Ensure no cross-contamination between pneumatic and hydraulic systems |
4 | R431002834 | P -050973-00004 P 050973-4 P 50973-4 P050973-4 P50973-4 | HD-2-X | 0-150 psi | 9 lb | Aluminum alloy body, NBR seals, carbon steel internal springs, stainless steel sensors | 1. Physical damage to valve ports from improper tubing installation; 2. Seal leakage due to worn O-rings; 3. Corrosion from moisture in outdoor installations | 1. Use proper tube fittings and avoid forcing tubing into ports; 2. Replace O-rings every 6 months or if leaks are detected; 3. Use a weatherproof enclosure for outdoor valve mounting |
Category 4: Rexroth HD-2-XS CONTROLAIR Valve
The Rexroth HD-2-XS CONTROLAIR Valve is a specialized precision model (9 lb weight) with a 0-65 psi pressure range. A key pain point is precision loss due to internal contamination, critical in sensitive applications. It delivers ultra-accurate pressure regulation (±1 psi tolerance), ideal for precision industrial equipment, laboratory automation, and delicate process control systems where consistency is paramount.
No. | Item # | Old Part# | Model | Pressure Range | Weight | Material | Main Wear Causes | Usage Notes to Avoid Damage |
1 | R431009025 | P -067556-00001 P 067556-1 P 67556-1 P067556-1 P67556-1 | HD-2-XS | 0-65 psi | 9 lb | Anodized aluminum alloy body, Viton precision seals, titanium internal sensors | 1. Micro-contamination (e.g., dust, lint) causing precision sensor wear; 2. Seal damage from improper cleaning; 3. Pressure fluctuations exceeding ±5 psi damaging precision components | 1. Install a 1-micron HEPA air filter upstream for ultra-clean air supply; 2. Clean valve only with compressed air (low pressure) or dry nitrogen; 3. Use a pressure stabilizer upstream to minimize fluctuations |
On-Site Fault Maintenance Case
Case 1: Rexroth HD-2-FX (Item # R431002824) Pressure Drift & Leakage
Fault Phenomenon: A manufacturing plant reported pressure drift (from 80 psi to 65 psi) and air leakage in their Rexroth HD-2-FX valve (Item # R431002824, 0-100 psi), causing downstream pneumatic cylinders to operate slowly and inconsistently—disrupting production efficiency.
Cause Analysis: After inspection, the NBR seals were found to be thermally aged and cracked (ambient temperature near the valve exceeded 150°F), and the air filter upstream was clogged with dust and moisture—allowing contaminants to wear internal components. This violates Rexroth’s recommended operating temperature range (32°F-140°F, per Rexroth Pneumatic Valve Specification Sheet 050970).
Solution: Replace the aged NBR seals with original Rexroth parts; clean and replace the clogged air filter element; reposition the valve away from high-temperature equipment to ensure ambient temperature stays within 32°F-140°F; calibrate the pressure regulator to 80 psi and secure with a locking nut. Post-repair, the valve maintained stable pressure with no leakage, and production resumed normally.
FAQ (Frequently Asked Questions)
No. | Question | Answer |
1 | Can I use Old Part# (e.g., P050970-1) to replace the corresponding Item # (e.g., R431002823) for Rexroth HD-2-FX valves? Are they compatible? | Yes, all listed Old Part# are fully compatible with their corresponding Item #. Rexroth updated the part numbering system (from Old Part# to Item #) for inventory standardization, but the valve design, specifications, and dimensions remain identical. For example, Old Part# P050970-1 is a direct replacement for Item # R431002823 (HD-2-FX, 0-65 psi). Always confirm the Model and Pressure Range to ensure compatibility, regardless of part number version. |
2 | What is the difference between HD-2-FX, HD-2-LX, HD-2-X, and HD-2-XS models? How do I choose the right one for my application? | The key differences lie in durability features and precision: HD-2-FX (standard durability, general use); HD-2-LX (anti-corrosion coated body, Viton seals, ideal for high-humidity/outdoor use); HD-2-X (standard model, versatile for general industrial automation); HD-2-XS (precision model, ±1 psi tolerance, for sensitive applications like laboratory automation). Choose based on environment (humidity, temperature), precision needs, and application type—all models share 9 lb weight and 4 pressure range options (except HD-2-XS, only 0-65 psi). |
Procurement Guidance
The reliable operation of your industrial pneumatic systems depends on using genuine, compatible Rexroth HD-2-X CONTROLAIR Valve parts. As precision control components, choosing the wrong or low-quality valves can lead to system inefficiency, downtime, and costly repairs—critical pain points for industrial operations. To ensure successful procurement and avoid risks, we provide the following professional guidance:
First, confirm key specifications before purchasing: Always match the Model (HD-2-FX/HD-2-LX/HD-2-X/HD-2-XS), Pressure Range, Item # or Old Part# (both are compatible) to your application needs. Incorrect pressure range or model selection will cause system malfunctions—e.g., using a 0-65 psi valve in a 100 psi system will lead to overpressure damage.
Second, prioritize genuine Rexroth parts. Genuine valves meet Rexroth’s strict quality standards (compliant with ISO 1219-1:2012, the international standard for pneumatic control valves) and ensure perfect compatibility with your existing Rexroth systems. Genuine parts also come with reliable material quality (aluminum alloy bodies, high-grade seals) and performance guarantees, reducing long-term maintenance costs.
Third, utilize both Item # and Old Part# for procurement: Since Old Part# are direct replacements for their corresponding Item #, you can use either to source parts—this flexibility simplifies procurement, especially if your inventory uses the old part numbering system. Always provide the full Old Part# (including all variations listed) to avoid mismatches.
We are dedicated to supporting your procurement needs for Rexroth HD-2-X CONTROLAIR Valve series. Whether you need single valves or batch procurement, we offer accurate part matching, professional specification verification, and guidance to help you choose the right model for your application. By investing in genuine, compatible valves, you ensure long-term system reliability, minimize downtime, and protect your industrial operations.
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