Device Description: EMD Series Automatic Electronic Condensate Drains
The EMD series of devices are electronically controlled automatic condensate drains designed to discharge condensed water from the lowest parts of compressed air installations. This includes air compressors, air receivers/pressure vessels, air dryers, and air filters. The condensed water is a result of water vapor, always present in the atmosphere, condensing during air compression due to physical laws.
Function Description
The EMD series drains operate by detecting when the water tank is full using a water level sensor. Once the threshold is reached, the electronics activate an electromagnetic valve to discharge the condensed water from the compressed air system. The valve assembly is designed for easy replacement and includes a strainer to intercept solid debris. This strainer is conveniently located at the front of the EMD for accessibility.
The condensed water discharged by the EMD may still contain small particles of rust and compressor oil. To ensure proper disposal into the sewage system, the oil must be removed, typically using a water-oil separator (WOS or WOSm device).
The EMD can be installed either horizontally or vertically, depending on the specific application. Horizontal installation is preferred under pressure vessels or refrigerator dryers, while vertical installation is more suitable under filters. The device should not be rolled more than ±15° from its intended horizontal or vertical position.
The valve operation is electronically controlled. It can be opened by pressing a test button on the electronics cover or automatically when the water level in the tank reaches a predefined threshold. A timed venting mode is also available, combining water level-triggered discharging with periodic timed venting.
The primary mode of operation is water level-triggered discharging. In this mode, the valve opens when the water level in the EMD's tank reaches the threshold and closes before the tank is completely empty, preventing the loss of compressed air.
The timed venting mode also opens the valve when the water level reaches the threshold. Additionally, if the valve remains closed for a predetermined period, it will open briefly even if there is no water in the tank. This feature is particularly useful in situations with significant debris in the condensed water or when the piping leading to the EMD cannot be sufficiently inclined. In such cases, trapped air might prevent condensed water from reaching the sensor, causing the EMD to remain closed. The timed venting allows this trapped air to escape, enabling the condensed water to reach the sensor and be discharged. While this mode involves short, sparse discharges during production rests, the air losses are minimal.
Important Technical Specifications
The EMD series includes several models: EMD 12, EMD 25, EMD 75, and EMD 150, each with different voltage options (230V ac, 115V ac, 24V ac, 24V dc).
General Specifications (may vary slightly by model):
- Operating Pressure Range: 1 - 16 bar (14 - 232 psi)
- Operating Temperature Range: 1.5°C - 65°C
- Protection Class: 54
- Inlet Connection: G 1/2" (parallel thread)
- Outlet Connection: Push connection for tube Ø8
- Fuse Inside EMD: 5x20 1A T
Model-Specific Drain Capacity (@7 bar / 101 psi):
- EMD 12: 12 l/h (0.007 cfm)
- EMD 25: 25 l/h (0.014 cfm)
- EMD 75: 75 l/h (0.044 cfm)
- EMD 150: 150 l/h (0.088 cfm)
Model-Specific Power Consumption:
- EMD 12 (230V/115V ac): 10VA
- EMD 12 (24V ac): 2A
- EMD 12A (24V dc): 8.5W
- EMD 25 (230V/115V ac): 22 VA
- EMD 75 (230V/115V ac): 22 VA
- EMD 150 (230V/115V ac): 22 VA
Model-Specific Mass and Dimensions (A x B x C x D / E [mm]):
- EMD 12: 0.55 kg, 133 x 76 x 147 x 65
- EMD 25: 0.73 kg, 140 x 85 x 166 x 65 x 72.5
- EMD 75: 1.2 kg, 170 x 99 x 162 x 74 x 60
- EMD 150: 1.3 kg, 199 x 99 x 162 x 70 x 68
Service Network and Alarm (for 'C' variants):
EMD variants with communication electronics and a connector can be integrated into a Service Network for remote supervision and parameter setting. The Service Network uses a communication protocol (SN-02.000) and consists of a slave device (EMD) and a master device (e.g., Service Network Reader SN-10.200). An alarm output is also included, which is an open collector output sharing its GND with the serial communication. It is in a high impedance state during an alarm and a low impedance state during normal operation. The EMD 12 24Vdc version has a built-in NO relay for alarm signaling, which closes when the EMD operates normally.
Usage Features
- No Loss Drain: The main mode of operation ensures only condensed water is discharged, preventing compressed air loss.
- Fixed Horizontally or Vertically: The device can be mounted in either orientation for installation flexibility.
- Easily Reachable Strainer: The strainer is located at the front of the EMD for convenient access and cleaning.
- Optional Timed Venting Mode: This mode addresses issues with trapped air and heavy debris, ensuring proper drainage.
- Optional Alarm/Warning Output and Service Network Protocol: For remote supervision and diagnostics (available on 'C' variants).
- Elapsed Hour Counter, Valve Operating Counter, and Other Data Collection: Provides valuable operational data.
- Easy Replacement of Parts: Designed for straightforward maintenance.
Maintenance Features
- Strainer Cleaning: The strainer insert should be cleaned regularly to intercept solid particles and prevent clogging. This involves closing the ball valve, pressing the test button to depressurize the EMD, removing the strainer insert, cleaning it, and then reinserting it.
- Valve Assembly Replacement: The valve assembly can be replaced by unscrewing the connector bolt and four screws, then pulling out the assembly. Ensure the electrical power supply is disconnected before performing this.
- Test Button: Allows manual discharge of collected water, useful for verifying operation and during maintenance.
- Troubleshooting Guide: Provides solutions for common issues such as overload, no LED signal, blown fuse, air leaks, no water in the tank, and red LED flashing.
- Spare Parts: Specific service kits are available for EMD 12, EMD 25, EMD 75, and EMD 150 models, including valve assemblies with strainer inserts. Valve connectors, replacement sealings, and bolts are also available on demand.
Safety Instructions:
- Installation and maintenance must only be performed when the device is not under pressure and by trained, experienced personnel using proper safety equipment.
- Always disconnect the electrical power supply before opening the electronic compartment or performing any electrical work.
- Do not exceed the maximal operating pressure or temperature range specified on the data label.
- The device is not intended for use in hazardous areas with potentially explosive atmospheres.
- Only original spare parts should be used.
- The device should only be used for its intended purpose: draining condensate from compressed air systems. Any other use is considered inappropriate and voids liability.
Installation Guidelines:
- Connect the EMD to the pressure system via a ball valve and pipe union to allow for maintenance without depressurizing the entire system.
- Ensure the inlet connection has a parallel thread; tapered threads should not be used.
- Avoid connecting multiple condensate sources to a single drain device to prevent air bypass. Each collection point should have its own drain.
- Drainage piping must be built without traps to prevent air or debris from accumulating.
- Horizontal drainage pipes should be inclined to allow air to escape and debris to be flushed towards the EMD. For long horizontal pipes, venting should be incorporated.
- If the bottom connection is used, the upper connection's height must be lower than the lowest point of the condensate level, and any unused upper connections must be properly sealed.
- Venting can be achieved via a T-piece located just in front of the valve (for upper inlet connections only) or through an auxiliary inlet (if implemented).
- Electrical wiring should be done according to valid regulations, with wires fitted firmly into terminals and equipped with appropriate ferrules.
- The EMD should be protected separately from heavy inductive loads like compressor motors.
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