Donaldson UFM-P Pneumatic Level-Controlled Condensate Drain

A zero-loss condensate drain that runs without electricity

The Donaldson UFM-P is a pneumatic, level-controlled condensate drain for compressed air systems. It measures the condensate level hydrostatically with a stainless steel float and operates a double-membrane servo valve with compressed air, so it needs no electricity. The data sheet states that it is suitable for operation in explosion-endangered areas, and it has a manual override for testing the outlet valve.

Large drain bores let it discharge big volumes of condensate and pure oil reliably, and the low height of the unit keeps the space needed to a minimum. It is built for zero-loss draining, which means the valve closes when the float drops, so compressed air is not blown out with the water.

Technical specifications

Where it is used

Donaldson lists compressors, aftercoolers, receiver vessels, the pre- and after-filters of refrigerated dryers, pre-filters of adsorption dryers, condensate and oil removal filters, and pipe bends as drain points. Typical industries are chemical and pharmaceutical, PCB assembly, surface finishing, machine building and power generation.

The function is simple. Condensate drips into the vessel and the control valve stays closed while the surge chamber is vented, so the operating pressure holds the diaphragm on its seat. When the float rises, compressed air enters the surge chamber, opens the diaphragm by means of the piston and the condensate leaves through the outlet. When the float falls, the valve closes and the chamber is vented again.

Choosing a drain

The UFM-P is the choice where electrical supply is not available or is not permitted in the area; the electronic UFM-D is the alternative for general plant air. Because the drain is air-operated, check that the control air is clean enough and that the system pressure is within the 0.8 to 16 bar window before ordering. Hazardous-area suitability depends on the zone and the certification required by the site, so confirm it with the manufacturer.

Typical piping is a short, rising condensate line from the point to the 1 inch inlet, a ball valve for isolation and a 1/2 inch outlet line to the treatment point or to an oil-water separator. A float of stainless steel and an aluminium housing with a polyester coat suit wet and corrosive plant rooms, though the sheet does not give a corrosion rating for particular media. Service work is limited because the unit has few moving parts.

Documents and quotation

Write to us about UFM-P via the quote form. Settle the operating pressure and whether the area needs a hazardous-area certificate with the attached Donaldson UFM-P pneumatic condensate drain data sheet (F119055) before we answer. See Compressors.

Donaldson UFM-P Technical Specifications

The following values are taken from the official Donaldson UFM-P datasheet (brochure F119055). Always confirm the data for your exact ordering code against the current manufacturer documentation before installation.

How the UFM-P Condensate Drain Works

The UFM-P uses hydrostatic level measurement combined with a pneumatic double-membrane servo valve. Because it needs no electrical power, all switching energy is taken from the compressed air system itself.

Collecting phase

Condensate enters through the intake port and collects in the vessel. While the level is low, the float-operated control valve stays closed, the surge (control) chamber is vented and the main diaphragm rests on its seat, so the outlet is sealed and no compressed air escapes.

Discharge phase

As the condensate level rises, the stainless steel float lifts and opens the control valve. Compressed air then flows into the surge chamber, where it acts on a diaphragm that moves a piston. The piston lifts the main diaphragm from its seat and the condensate is pushed out through the drain channels to the outlet. Because the drain bores are large, oily condensate and even pure oil can be discharged without blockage.

Closing phase

Once the level falls, the float closes the control valve again. The surge chamber vents through a small nozzle, the main diaphragm returns to its seat and the outlet closes before any compressed air can be lost. This level-controlled principle avoids the compressed air losses typical of timer-controlled solenoid drains, which open on a fixed cycle regardless of how much condensate is present.

Key Features and Benefits

• No electricity needed – the purely pneumatic operation makes the UFM-P suitable for locations where electrical equipment is restricted, such as hazardous areas. Confirm the applicable certification for your zone with the manufacturer documentation.
• Problem-free drainage of oil – hydrostatic level measuring handles oil-contaminated condensate and pure oil.
• Long service life – the double-membrane servo valve is designed for a high number of switching cycles.
• Large drain bores – reduce the risk of clogging by dirt, rust and sludge.
• Manual override – a hand valve allows quick function checks during routine rounds.
• Almost maintenance free and a small unit height for installation under filters and dryers.

Selection & Ordering Guide

When selecting a UFM-P pneumatic drain, check the following points:

• System pressure: the drain needs a minimum of 0.8 bar to operate and must not exceed 16 bar.
• Condensate volume: compare the expected condensate load at the drain point with the rated capacity of 450 l/h at 7 bar. Condensate volume depends on compressor capacity, ambient temperature and humidity – a key consideration in the humid coastal climate of Oman and the Gulf.
• Temperature: the medium temperature must stay within +1 °C and +80 °C; protect the drain from freezing and from very hot condensate directly at the compressor discharge.
• Connections: 1" BSP inlet and 1/2" BSP outlet; plan adapters if your pipework uses NPT threads.
• Power availability: if electrical supply and an alarm output are required, the electronic UFM-D series may be the better choice; if no power is available or wanted, the UFM-P is the natural option.

Our team can help confirm the correct ordering code and compare the UFM-P with other Donaldson condensate drains for your application.

Installation & Maintenance

• Install the drain vertically below the drain point so that condensate can flow to it by gravity. Use an inlet line with a continuous fall and avoid water pockets.
• Fit an isolating ball valve upstream so that the drain can be serviced without depressurising the whole system.
• Make sure the inlet line allows air in the drain housing to escape back to the system; otherwise an air lock can prevent condensate from entering.
• Route the outlet to a suitable oil-water separator. Oily compressor condensate must not be discharged directly to drains or soil.
• Use the manual override hand valve during regular inspections to confirm the drain is discharging correctly.
• Although the design is almost maintenance free, inspect periodically for external damage, leaks and contamination, and follow the manufacturer manual for service intervals and spare parts.

Typical Applications in Oman & the GCC

The datasheet lists compressors, aftercoolers, air receivers, pre- and after-filters of refrigerated dryers, pre-filters of adsorption dryers, condensate and oil-removal filters and pipe bends as typical drain points. Industries named include chemical and pharmaceutical, PCB and CD manufacturing, surface finishing, machine building, and energy and power generation.

In Oman and the wider GCC, the UFM-P pneumatic level-controlled drain is a practical choice for:

• Oil and gas facilities, refineries and petrochemical plants where electrical equipment in classified areas must be minimised.
• Power and desalination plants with instrument air systems that run continuously in hot, humid conditions.
• Remote compressor stations and skids where no electrical supply is available at the drain point.
• Manufacturing plants, cement and mining sites that want to stop air losses from open bleed valves and timer drains.

Why Source from Seven Star LLC

Seven Star LLC supplies Donaldson compressed air filtration and condensate management products across Oman and the GCC. Send us the model, quantity and your operating conditions to request a quote, and our team can help confirm the correct ordering code, connection sizes and any matching filters or separators for your compressed air system.