IntroductionThis user guide provides detailed instructions for the installation, operation, maintenance, and repair of MDCW Carousel Plus
Dryer models 15, 25, 50, 75, and 100, featuring DC-1 controls. It highlights the importance of recording equipment details for service and emphasizes user responsibilities, including adherence to safety procedures and thorough review of the guide and equipment manuals.
Description
The MDCW Carousel Plus Dryer is a mobile unit designed for drying plastic resin and conveying it using dehumidified air to a processing machine. It includes a dehumidifying dryer, drying hopper, conveying blower, and direct feed machine loader. It is suitable for contamination-free drying, with temperatures ranging from 100° to 375°F, throughput rates of 15 to 100 lbs per hour, and dewpoints of -40°F. Conveying is effective up to 8 feet vertically.
Installation
Installation involves unpacking, site preparation, connecting conveying lines, demand sensors, and main power, ensuring proper airflow, and following safety and grounding procedures to prevent electrical hazards.
Operation
The operation section details the use of the DC-1 control panel, including starting and stopping drying, conveying, and using features like auto start countdown and dewpoint control. It includes a flow chart and descriptions of control functions for efficient operation.
Maintenance
Regular maintenance is crucial for optimal performance. The guide includes a preventative maintenance checklist and instructions for cleaning components such as the hopper, filters, and coils, and advises on inspecting hoses and gaskets.
Troubleshooting
This section offers diagnostics and repair guidance, including identifying problems, addressing alarms, and troubleshooting dewpoint and drying issues. It covers replacing fuses, checking relays, and replacing heaters and the desiccant wheel assembly.
Appendices
The appendices provide contact information for customer service, warranty details, and additional cleaning instructions for specific components.
Specifications
The MDCW Carousel Plus Dryer supports drying temperatures from 100°F to 375°F, throughput rates of 15 to 100 lbs per hour, and achieves dewpoints of -40°F. Options include aftercoolers for high-temperature drying and precoolers for low-temperature settings.
Process Cycle
The drying process involves a blower pulling moist air through filters and a desiccant wheel to remove moisture. The air is then heated to the desired drying temperature and distributed evenly through the material in the hopper. The cooling cycle involves cooling the regenerated desiccant before it re-enters the process cycle.
Regeneration Cycle
Air is heated to 350°F to purge moisture from the desiccant, which is then expelled through the exhaust.
Conveying Process
The MDCW uses dry air to transport material from the drying hopper to the process machine. The system includes a vacuum receiver and a blower that operates based on material demand, ensuring continuous supply.
Options and Recommendations
High-heat models are recommended for drying temperatures over 180°F. An aftercooler is advised for batch drying over 160°F or when throughput is below 50% capacity. Additional filtration may be necessary for materials with excessive fines or volatile production.
Technical Specifications
The document provides detailed specifications for various models, including airflow rates, dimensions, weight, voltage requirements, and water and compressed air needs. It advises consulting a representative for the latest information.
Installation Procedures- Connecting the Main Power: Ensure the main power is disconnected and locked out before making electrical connections. Only qualified personnel should perform these tasks. Follow the wiring diagrams provided with the dryer.
- Checking for Proper Air Flow: This is crucial for non-conveying MDCW models 50, 75, and 100. Ensure the airflow direction is correct before filling the hopper with material to prevent damage.
- Mounting a Loader on the Hopper: Use the provided flange and mounting clips. Ensure material conveying hoses are away from the control panel to avoid static electricity damage.
- Connecting the Aftercooler: Requires a cooling water source and discharge line. Use flexible hoses for easy removal and cleaning.
- Testing the Installation: Verify all components are functioning correctly before loading the hopper and beginning operation.
Operational Procedures- Control Panel Functions: The MDCW dryer control panel (DC-1) includes various functions such as auto start, dewpoint control, and setback temperature options. The control panel displays setpoints and actual values for process and regeneration temperatures.
- Starting and Stopping Drying: Use the start and stop buttons on the control panel. The auto start function can be set for a countdown time, and the dryer will begin operating once the countdown is complete.
- Alarm Codes: The system includes shutdown and passive alarms for various conditions such as high temperature and blower overload. Refer to the troubleshooting section for a complete list of alarms.
Key Recommendations- Always refer to the wiring diagrams and follow electrical codes for your region.
- Ensure proper airflow direction before operation to prevent damage.
- Use flexible hoses for aftercooler connections to facilitate maintenance.
- Regularly test the installation to ensure all components are functioning correctly.
Overview
This document provides detailed instructions and specifications for operating a drying system, including setup, test modes, and alarm management. It outlines the control functions, temperature settings, and procedures for starting and stopping the drying process.
Specifications
The system operates with a minimum sensor range of -40°F (-40°C). The process temperature setpoint can be adjusted between 100°F and 450°F (38°C to 232°C), although it is recommended not to exceed 375°F (191°C) to avoid nuisance alarms. Dewpoint control is enabled with a setpoint present, but will not activate if the setpoint equals -40°F (-40°C).
Control Functions
Access to setup, test mode, and alarm history screens requires specific access codes (754 for setup, 755 for test mode, and 756 for alarm history). The document details various screens for setting up and testing different components like process heaters, blowers, and temperature controls.
Procedures- Starting the Dryer: Ensure material is in the hopper, turn on the main power, set the drying temperature, and press the start button. The green light indicates successful startup.
- Stopping the Dryer: Press the stop button, allowing blowers to cool the heaters. Avoid using the main power switch to stop the dryer to prevent triggering alarms.
Alarms
The document categorizes alarms into shutdown alarms (e.g., process high temp, process heater high temp) and passive alarms (e.g., process temp deviation). It provides a list of alarm codes and advises referring to the troubleshooting section for definitions.
Recommendations
Perform autotune on a cold dryer, ensure normal drying temperature is set before autotuning, and follow proper shutdown procedures to avoid damage. The document also advises against setting excessively high drying setpoints not in accordance with material recommendations.
Specifications and Procedures- Load Time and Delay Adjustment: Set the load time and adjust delay time as necessary before starting the conveying process.
- Auto Start Countdown: Allows the dryer to start automatically at a predetermined time, adjustable from 0.1 to 150.0 hours.
- Disabling Auto Start: Cycle the power off and on to disable the auto start function.
Setting High Setpoint Limits- Protects the drying process from unauthorized settings. Recommended to set limits 10° higher than the maximum temperature setpoint.
- Conair advises against setpoint limits over 375°F due to potential alarms.
Dewpoint Control- Reduces energy consumption by adjusting regeneration air temperature based on the process dewpoint screen settings.
- Active with setpoint values of -39°F and higher; inactive at -40°F or lower.
Setback Feature (Optional)- Designed to save energy and prevent over-drying by adjusting air temperature based on customer-set parameters.
- Requires careful selection of setpoint values for optimal operation.
Maintenance- Preventative Maintenance Checklist: Includes tasks like cleaning the hopper, filters, and inspecting hoses and gaskets.
- Dewpoint Checking: Regular monitoring with a portable dewpoint monitor is recommended to ensure performance.
- Cleaning Procedures: Detailed steps for cleaning the hopper, process filter, and regeneration filter to maintain efficiency.
Maintenance Procedures- Filter Cleaning: Use a small screwdriver to remove the filter grill, clean the filter with soap and water, and replace it securely. Ensure the control cabinet is closed during operation to filter regeneration air.
- Conveying Filter: Turn off the conveying function, remove and clean or replace the filter to maintain airflow and performance.
- Vacuum Receiver: Clean the vacuum receiver and replace the mesh filter if damaged. Disconnect hoses, clean the receiver and viewing chamber, and reassemble.
- Aftercooler Coils: Stop the dryer, disconnect water lines, remove the aftercooler, clean it, inspect the gasket, and reassemble.
- Precooler Coils: Clean the optional precooler coils as needed.
- Hoses and Gaskets Inspection: Inspect and tighten or replace any loose or damaged hoses and gaskets.
Troubleshooting and Alarms- Alarm Types:
- Shutdown Alarms: Indicate serious issues causing automatic dryer shutdown.
- Passive Alarms: Warn of potential problems without stopping the dryer.
- Common Alarms:
- Process High Temp: Caused by incorrect setpoints or failed relays.
- Process Loop Break: Triggered by temperature deviations.
- Heater High Temp: Due to excessive temperatures in heater tubes.
- Return Air High Temp: Occurs when return air temperature exceeds limits.
- Alarm Resolution: Use the control panel to diagnose and resolve alarms. Follow wiring diagrams for specific issues.
Repair Procedures- Fuse Replacement: Check and replace fuses as needed.
- Heater and Sensor Checks: Inspect and replace solid state relays and temperature sensors.
- Desiccant Wheel Replacement: Follow specific steps for replacing the desiccant wheel.
Troubleshooting and Alarms Overview
Alarms:
1. Shutdown (A#): The dryer automatically shuts down due to a serious problem that could damage the material or dryer.
2. Passive (P#): The dryer continues to operate but warns of a problem that could prevent correct drying. Ignoring this could lead to a shutdown.
Common Problems and Solutions:
Process RTD Integrity (A10 & P26):
- Problem: Faulty process RTD can shut down the dryer.
- Causes: Loose connections, failed RTD, or control board issues.
- Solutions: Tighten connections, replace RTD or control board.
Process Temperature Deviation (A21 & P1):
- Problem: Temperature exceeds deviation band.
- Causes: Loose RTD, failed heater, or SSRs.
- Solutions: Tighten connections, replace failed components.
Regeneration Temperature Deviation (A23 & P3):
- Problem: Temperature exceeds deviation band.
- Causes: Loose RTD, defective heater.
- Solutions: Tighten connections, replace heater.
Return Air Mid-High Temperature (A25 & P5):
- Problem: Return air temperature is too high.
- Causes: High drying temperature, insufficient water in aftercooler.
- Solutions: Adjust drying temperature, ensure water flow.
Regeneration High Temperature (A26 & P6):
- Problem: Temperature exceeds high limit.
- Causes: Failed SSRs, control board issues.
- Solutions: Replace failed components.
Process Dewpoint (A28 & P9):
- Problem: Dewpoint not below setpoint.
- Causes: Poor airflow, contaminated desiccant.
- Solutions: Remove airflow restrictions, replace desiccant.
Process Protection High Temperature (A49):
- Problem: Temperature exceeds setpoint.
- Causes: Incorrect RTD installation, non-functioning blower.
- Solutions: Correct installation, fix blower issues.
Process Protection Differential (A50):
- Problem: Temperature difference too high.
- Causes: Restricted air lines, loose hoses.
- Solutions: Check for blockages, tighten hoses.
General Recommendations:
- Regularly check and tighten all connections.
- Ensure proper installation and functioning of all components.
- Maintain clean and unobstructed air and water flow systems.
- Replace faulty components promptly to prevent further issues.
Troubleshooting Alarms- Shutdown (A#): The dryer shuts down automatically due to a serious problem that could damage the material or dryer.
- Passive (P#): The dryer continues to operate but warns of a problem that could lead to a shutdown if ignored.
Common Problems and Solutions- A53 - Process Blower Overload: Occurs when the blower exceeds its amp rating or due to mechanical/electrical issues. Solutions include checking current draw, mechanical failures, electrical shorts, and overload settings.
- A54 & P23 - Conveying Blower Overload: Similar issues as the process blower, with solutions involving mechanical and electrical checks, and overload settings.
- A55 & P31 - Wheel Rotation Failure: Caused by motor or belt issues, with solutions involving checking motor, belt, and heater.
- A56 & P32 - Regeneration Outlet RTD Integrity: Involves checking RTD connections and replacing faulty components.
- P34 & P35 - Dewpoint Deviation: Caused by sensor issues or airflow problems, with solutions involving checking connections, airflow, and replacing sensors if necessary.
Additional Alarms- CoS Er.4 or Co5 Er.4: Indicates an active alarm when the "Start" button is pushed.
- CoS Er.0 or Co5 Er.0: Communication issue between control and display boards.
- Err 004: Software mismatch between display and control boards.
- Er. L: Sensor connection problem.
- Er. H: Analog input section issue.
Dewpoint Troubleshooting- Dryer not producing desired dewpoint: Caused by high return air temperature, low regeneration temperature, or leaks. Solutions include adjusting temperatures, checking filters, and verifying dewpoint readings.
Poor Material Drying Troubleshooting- Temperature: Ensure air entering the hopper is at the correct drying temperature.
- Residence Time: Ensure material has adequate time to reach drying temperature.
- Airflow: Ensure adequate airflow to distribute heat throughout the material.
Troubleshooting and Maintenance Guide for Dryers
1. Material Level and Airflow: Ensure the hopper is at least 50% full to maintain adequate airflow for proper drying. Excessive airflow can cause material fluidization, leading to inconsistent flow and residence time issues.
2. Dewpoint Management: The process air should have a low dewpoint (-20 to -40°F) for efficient moisture removal. If the dewpoint is not reached, check for low regeneration temperature, poor airflow, or leaks in the drying circuit.
3. Electrical Checks: All electrical checks should be performed by qualified personnel. This includes checking and replacing fuses and ensuring proper operation of solid-state relays.
4. Temperature Sensors: RTD sensors monitor various temperatures. Ensure they are correctly positioned and not damaged. Resistance should be approximately 110 ohms at room temperature.
5. Heater Replacement: Follow lockout procedures before replacing regeneration or process heater tubes. Ensure new heaters match the original specifications and are properly insulated and secured.
6. Desiccant Wheel Replacement: Replace the desiccant wheel if clogged or contaminated. Follow proper disassembly and reassembly procedures, ensuring all connections are restored to their original positions.
7. Customer Support: Conair provides extensive customer support. Before contacting them, ensure all equipment details are available, power is supplied, and troubleshooting steps have been followed.
8. Warranty Information: Conair offers a guarantee against defects and a performance warranty, with specific conditions and limitations outlined.
9. Precooler Coil Cleaning: Regular cleaning of precooler coils is necessary for efficient operation. Follow the specified steps for disassembly, cleaning, and reassembly.