FULL-SIZE, HIGH-CAPACITY, MD3, MD4 FULL-SIZE, HIGH-CAPACITY, MD3, MD4

Product Overview

The ROSS Controls provides external automatic drain accessories for ROSS Full-Size, High-Capacity, MD3, and MD4 FRL filter bowls. These float-operated mechanical drains automatically expel accumulated condensate from the filter bowl without operator intervention, maintaining filter effectiveness and preventing water carryover to downstream pneumatic equipment.

The Series offers four models combining pipe size (1/8 and 1/4 inch) with bowl type compatibility (polycarbonate or metal bowl). The 5057B series (1001 and 2001) are designed for polycarbonate bowl installations, while the 5058B series (1001 and 2001) are designed for metal bowl installations. The 1/4 inch pipe size models (5057B2001 and 5058B2001) are compatible with Full-Size, High-Capacity, MD3, and MD4 filter installations; the 1/8 inch models cover standard Full-Size filter installations.

Each external automatic drain unit connects to the filter bowl drain port and uses a float mechanism to detect accumulated liquid. When condensate level rises to the trigger point, the float actuates a valve that releases the liquid through the drain outlet. When the bowl is dry, the valve closes automatically, preventing air loss. This cycle repeats without operator involvement, ensuring continuous filtration at full effectiveness.

The Series drains are rated to 290 psig (20 bar) maximum operating pressure, covering the full pressure range of ROSS Full-Size, High-Capacity, MD3, and MD4 FRL filter products. For applications where condensate accumulation is rapid or where unattended operation requires automated drain management, the series eliminates the maintenance burden of manual drain monitoring and operation.

Key Engineering Features

• Float-Operated Automatic Draining - Mechanical float mechanism detects accumulated condensate and actuates the drain valve automatically without electricity, pneumatic pilot signals, or operator interaction, providing continuous drain function at any time of day or night.
• Compatible with Full-Size, High-Capacity, MD3, and MD4 Filters - The 1/4 inch pipe size models (5057B2001 and 5058B2001) connect to Full-Size, High-Capacity, MD3, and MD4 filter bowl drain ports; the 1/8 inch models provide standard Full-Size filter coverage.
• Polycarbonate and Metal Bowl Options - Separate model families for polycarbonate bowl (5057B series) and metal bowl (5058B series) installations, ensuring correct fit and compatibility with the installed filter bowl type.
• 290 psig Rated - External drain units are rated to 290 psig (20 bar), compatible with the maximum operating pressure of Full-Size, High-Capacity, MD3, and MD4 FRL filter systems.
• Zero Compressed Air Loss During Non-Drain Periods - Float-actuated valve closes tightly when no condensate is present, preventing air loss through the drain port when the bowl is dry. This is a fundamental advantage over timed mechanical drains that open on a schedule regardless of bowl condition.
• No Electrical Power Required - Purely mechanical float operation requires no electrical supply, control wiring, or solenoid valves, simplifying installation and eliminating electrical failure modes.

Technical Specifications

General Specifications

Temperature Ratings

The Series external automatic drain temperature ratings apply to the condensate-contacting components of the drain unit.

Important: The external automatic drain is designed for use in compressed air systems where condensate is water-based. Do not use where the condensate contains corrosive chemicals, solvents, or oils that are incompatible with the drain body material. Polycarbonate bowl models must be used within polycarbonate temperature limits.

Certifications & Compliance

Typical Applications & Industries

Continuous Process and Unattended Operations

• Full-Size FRL filters in continuous process facilities (24-hour, 7-day operations) where manual drain checks cannot be performed frequently enough to prevent condensate accumulation during periods without operator presence.
• MD3 Series filter assemblies in remote or hard-to-access locations such as elevated machine platforms, underground areas, or confined spaces where regular manual drain inspection is impractical.
• High-Capacity filter installations in compressor rooms and main supply headers where high-volume compressed air carries significant moisture load, producing condensate faster than daily manual draining can manage.

Automotive Manufacturing

• MD4 Series filter assemblies in automated welding cells and robotic stations where downtime for manual drain servicing is unacceptable in high-production-rate environments.
• Full-Size filters in spray painting and surface treatment lines where moisture carryover from a manually drained filter can cause defects in coatings applied by pneumatic spray equipment.
• High-Capacity filter installations at main plant air supply headers in automotive body shops where 24-hour production schedules require unattended drain operation overnight.

Food and Beverage Processing

• MD3 and MD4 filter assemblies in food processing environments where manual drain intervals may miss condensate accumulation during high-humidity production periods, risking water contamination of product contact air.
• Full-Size filters in beverage production facilities where automated draining eliminates the risk of operator neglect during high-demand production periods with elevated compressor condensate output.
• High-Capacity filter assemblies in large food processing plants where centralized compressed air supply delivers air to multiple food-contact pneumatic systems requiring consistently dry, clean air.

General Industrial

• Full-Size FRL installations in multi-shift or lights-out manufacturing where overnight shifts have reduced maintenance staffing and manual drain monitoring cannot be guaranteed.
• MD3 Series filters at automated conveyor system supply points where access for manual drain servicing would require interrupting material handling operations.
• Large-scale pneumatic distribution systems where the quantity of filter installations makes manual drain management across all points a significant maintenance burden, justifying external automatic drains at all high-flow filter locations.

Ordering and Model Number Configuration

The Series external automatic drain accessories are ordered based on two parameters: pipe size (1/8 or 1/4 inch) and bowl type (polycarbonate or metal). Select the model that matches your filter installation.

Use 1/4 inch pipe size models (5057B2001 or 5058B2001) with Full-Size, High-Capacity, MD3, and MD4 Series filters.

Use 1/8 inch models for standard Full-Size filter installations; verify compatibility with specific filter model.

Polycarbonate bowl models (5057B series) require polycarbonate bowl filters (operating limit 125F/52C for ambient and media).

Metal bowl models (5058B series) are for metal bowl filters (operating limit 175F/80C for media).

Kit 1076K77 may be required to convert a standard filter bowl to accept the external auto drain unit. Verify with ROSS or filter model documentation.

For applications requiring timed or electronically controlled drain intervals, consider the 164 Series Electronically Controlled Drain instead of the series float drain.

Accessories

Series External Automatic Drain Model Selection

Select based on pipe size and bowl type.

Bowl Conversion Kit

Required on some filter models to adapt the standard bowl for external auto drain connection.

Related Products & Accessories

• 164 Series Electronically Controlled Drains - Timer and interval-controlled electronic drain for automatic condensate removal, for applications requiring programmable drain timing rather than float-operated draining. https://www.rosscontrols.com/en/series/164-electronically-controlled-drains
• Full-Size Series FRL Filters - ROSS Full-Size Series filters for 3/8, 1/2, and 3/4 inch ports with up to 180 scfm flow capacity. https://www.rosscontrols.com/en/categories/59-frl-accessories
• Series Companion: MD3 and MD4 FRL Units - ROSS MD3 (up to 110 scfm) and MD4 (up to 230 scfm) modular FRL series that use the series external drain accessories. https://www.rosscontrols.com/en/categories/59-frl-accessories
• 174 Series Differential Pressure Gauge - Visual filter element condition monitoring indicating when the element requires replacement. https://www.rosscontrols.com/en/series/174-differential-pressure-gauge
• 173 Series MD3 and MD4 Port Blocks - Male and female end port accessories for MD3 and MD4 Series FRL modular assemblies. https://www.rosscontrols.com/en/series/173-md3-md4

Frequently Asked Questions (FAQ)

Q: What is the difference between the 5057B and 5058B model series?

A: The 5057B series models are designed for use with polycarbonate bowl filters; the 5058B series models are for metal bowl filters. Selecting the wrong series will result in improper fit at the bowl drain connection. Always verify the bowl type of the installed filter before ordering.

Q: When should I use the 1/8 inch versus 1/4 inch pipe size drain?

A: Use the 1/4 inch pipe size models (ending in 2001) with Full-Size, High-Capacity, MD3, and MD4 Series filters as specified in the ROSS FRL catalog. The 1/8 inch models (ending in 1001) are for standard Full-Size filter bowl connections. Verify by checking the drain port size of the specific filter model.

Q: Does the external automatic drain require any electrical connection?

A: No. The Series external automatic drain is a fully mechanical float-operated device requiring no electrical supply, control wiring, or solenoid. It operates automatically based on condensate level alone.

Q: What is the maximum operating pressure of the series drain?

A: The Series external automatic drain is rated to a maximum of 290 psig (20 bar), exceeding the maximum pressure of the ROSS Full-Size, High-Capacity, MD3, and MD4 FRL filter systems it serves.

Q: How does the float-operated drain prevent air loss when the bowl is dry?

A: The float mechanism holds the drain valve closed when no condensate is present. When condensate accumulates to the trigger level, the rising float opens the drain valve. When the condensate drains and the float drops, the valve closes again. This ensures air is only released when condensate is actually present.

Q: What is the 1076K77 bowl conversion kit used for?

A: The 1076K77 kit converts a standard filter bowl that has an internal drain to accept the external automatic drain unit. Not all filter bowl configurations require this kit; check the filter model documentation or contact ROSS to determine if the 1076K77 is needed for your specific filter installation.

Q: Can the series drain be used with polycarbonate bowls in high-temperature environments?

A: Polycarbonate bowl filters (and the 5057B drain models designed for them) are rated to a maximum ambient and media temperature of 125F (52C). For higher temperature applications, specify metal bowl filter models with 5058B series drains.

Q: Can the series replace the need for the 164 Series electronically controlled drain?

A: The Series float drain and 164 Series electronic drain serve different operational needs. The float drain (Series) drains automatically based on condensate level and requires no electricity. The electronic drain (164 Series) operates on user-programmable timer intervals and provides drain cycle feedback. Choose based on whether timer control and electronic management are required for your application.

Q: Is the drain unit itself replaceable without removing the filter from service?

A: Yes. The external automatic drain connects to the filter bowl drain port and can be removed and replaced during a brief system shutdown without requiring full FRL assembly disassembly, reducing maintenance impact.

Q: What type of condensate can the series handle?

A: The Series drain is designed for water-based condensate from compressed air systems. Do not use in systems where the condensate contains corrosive chemicals, acids, solvents, or fluids that are incompatible with the drain body materials.

Q: Is maintenance required on the float drain mechanism?

A: The float drain is a low-maintenance device, but periodic inspection is recommended. Check the drain for free float movement and clean the drain valve if contamination accumulates. Filters with high particulate loading can deposit debris in the drain valve, requiring cleaning to restore automatic function.

Q: Where can I find technical drawings for the series drain?

A: Dimensional drawings and installation instructions are in the ROSS FRL catalog (Form A10120), available at rosscontrols.com. Contact ROSS Controls at (800) 438-7677 for direct technical support.

Installation & Maintenance Guidelines

• Confirm the filter bowl type (polycarbonate or metal) and drain port pipe size (1/8 or 1/4 inch) before selecting the series model number.
• Depressurize the FRL assembly completely before installing the external automatic drain.
• If required, install the 1076K77 bowl conversion kit following ROSS installation instructions to adapt the filter bowl drain port for external drain connection.
• Connect the external automatic drain to the filter bowl drain port. Apply appropriate thread sealant to NPT threads.
• Position the drain unit with the float chamber oriented so the float moves freely in a vertical plane. Consult ROSS FRL catalog for required installation orientation.
• Ensure the drain outlet is directed to a safe discharge point, as condensate will be expelled during automatic drain cycles.
• Pressurize the system and verify there are no leaks at the drain connection or float chamber.
• Test automatic drain function by observing that condensate is expelled when accumulated, and that the drain valve closes when the bowl is emptied.
• Do not restrict or cap the drain outlet, as this will prevent condensate removal and allow bowl overfill.

Warranty & Global Support

ROSS Controls provides a one-year warranty on all products, covering defects in material and workmanship from date of purchase.

Global technical support available through ROSS offices in the USA, Canada, Brazil, Germany, France, United Kingdom, India, China, and Japan.

Contact ROSS Controls USA at (800) 438-7677 or visit rosscontrols.com for product configuration, technical support, and distributor locator services.

For the complete FRL accessories catalog, dimensional drawings, and installation instructions, visit rosscontrols.com or contact ROSS Controls at (800) 438-7677.

Download Catalog: https://www.rosscontrols.com/en/series/163-full-size-high-capacity-md3-md4