13 Steps to Safely Clean and Maintain Heat Exchangers

Heat Exchangers

13 Practical Steps to Heat Exchanger Maintenance and Cleaning

A heat exchanger has a simple job. Exchange heat from one medium to another. If the heat exchanger is dirty or not maintained, it fails at this job, which increases costs to operate, stresses other parts of the systems, and reduces efficiency. Simple as that.

Heat exchanger maintenance and cleaning are important factors in operating at peak efficiency and safety. Cleaning a heat exchanger keeps it clean and free of fouling, increasing heat efficiency and lowering operational costs.

Understanding your type of heat exchanger can help you identify the cleaning and maintenance needs it may have. Some solutions will include mechanical tube cleaning solutions like rotary tube cleaning systems or projectile tube cleaning solutions, but increasingly more common will be chemical cleaning, especially in hard water areas or in applications where untreated water is used regularly.

Special Note: Safety should be the highest priority when cleaning heat exchangers. Protective gear and an awareness of the electrical and mechanical dangers that may exist are vital.

Understanding Different Types of Heat Exchangers

Heat exchanger maintenance relies on knowing what type of heat exchangers you have and developing a process to clean them.

Common heat exchanger types include:

  • Shell and Tube: Comprises a shell with tubes inside. It is most often used in industrial applications like refineries, chemical production, manufacturing, etc.
  • Plate and Frame: Stacked metal plates that create alternating hot and cold fluid channels. These heat exchangers are widely used in HVAC, refrigeration, and food processing.
  • Finned Tube: Tubes with finned surfaces for increased heat transfer area. These heat exchangers are commonly used in air conditioning, refrigeration, and heat recovery systems.
  • Double Pipe: Two concentric pipes with one fluid in the inner pipe and the other in the annular space. Most often used for low-pressure applications.
  • Spiral: Two coiled flat plates forming spiral channels, efficient for highly viscous or fouling-prone fluids.
  • Regenerative: Rotating matrix with heat-absorbing and heat-rejecting sections for heat recovery, commonly used in HVAC and industrial processes.

The heat exchanger type depends on the application, heat transfer requirements, fluid characteristics, space constraints, and operating conditions. Knowing which type a system uses dictates heat exchanger cleaning methods: mechanical using projectile cleaning, rotary tube cleaner, or chemical, like a chemical descaler.

Easy Steps to Heat Exchanger Maintenance and Cleaning

These steps will help technicians incorporate the best safety measures when cleaning heat exchangers with chemicals, such as ScaleBreak chemical descalers.

  1. Review the Manufacturer’s Guidelines. Examine the heat exchanger user manual and other manufacturer documentation to gather specific instructions and recommendations for maintenance procedures, suitable chemical cleaning agents, and safety precautions. Developing a heat exchanger maintenance checklist based on these steps ensures a consistent chemical cleaning process is always followed and avoids problems such as cracked heat exchangers.
  2. Wear Protection. Follow plant policy for personal protective equipment (PPE) such as safety goggles, gloves, and a respirator mask. Also, check any chemicals and cleaning solvent labeling or machinery for additional PPE needs.
  3. Shut off and Isolate. Make sure all inlet valves are securely fastened and tagged. Close the supply and return water valves. Position a ball valve on the low point of the heat exchanger, which will serve as an entry point for the cleaning agent and will prevent backflow. Shutting off all valves and isolation points to stop the flow of fluids through the system ensures a safe and inactive heat exchanger during the tube cleaning process. And lockout and tagout any electrical.
  4. Perform a Visual Inspection. A heat exchanger risk assessment checks for visible signs of damage, such as corrosion, cracks, or other abnormalities. Check for fouling or corrosion and identify the fouling to determine the optimal cleaning method. This may include chemical or mechanical cleaning or a combination of both: test inlet and outlet temperatures. Inspect tubes for damage and replace them if needed.
  5. Release Pressure and Drain Fluids. Ensure the heat exchanger’s pressure goes down using a safety relief device, checking that the pressure relief valve reads zero. Wait until the system cools before doing anything else to minimize exposure to hot fluids. High-pressure cleaning can reduce safety.
  6. Attach Hoses. Using a descaling system, which is chemical safe, attach a circulation hose to pump fluid into the bottom and return fluid from the top. The exit point must be at the exchanger’s highest point. This ensures the cleaning agent comes in contact with all interior wetted surfaces and that upper interior areas do not become air-bound with CO2 or foaming.
  7. Fill Up and Test. Fill the heat exchanger with water and perform a hydrostatic test by turning on the pump and circulating the water. This action assures the exchanger is isolated and none of the cleaning agents will be needlessly lost. Bleed-off water equal to the volume of chemicals required for cleaning. If too much water is bled off, add some back in to complete the circulation loop. Additional water may be needed during the cleaning process as deposits are dissolved to make sure dissolved deposits do not stick somewhere within the system.
  8. Check It Out. Periodically check isolation valves as they may have initially seated against the scale. As chemicals dissolve the scale, this action will help prevent product loss.
  9. Give It Time. Allow sufficient cleaning time. Circulate the cleaning agent for the recommended timeframe.
  10. Rinse Thoroughly. Empty the heat exchanger of dangerous chemicals after the solution has completed its job. To flush the heat exchanger, turn off the circulation pump, remove the return hose from the recirculation system, and put it in a drain. Add a freshwater hose to the recirculation bucket on the pump system and turn the pump back on. Run clean water through the heat exchanger until the return water is clear. This action will also flush out the pump system. As an added safeguard, technicians can reverse the hoses so they pump into the top and out the bottom. This will flush away debris that has settled on the bottom.
  11. Inspect and Reassemble. To avoid leaking, carefully install a new gasket focusing on the head. Poor installation can cause leakage. Disconnect the hoses. Close the valves used in circulation and open the valves for water supply. The heat exchanger can now be returned to service.
  12. Test and Restart. Perform required system checks and tests as the manufacturer recommends to ensure the heat exchanger functions properly. Once verified, restart the system while monitoring it closely for irregularities.
  13. Follow the Law. As the above steps are carried out, be sure to follow all local regulations for discharge. These can vary from city to city and state to state.

Next Steps?

Contact Goodway to discuss your specific heat exchanger cleaning needs. We can help from HVAC heat exchangers like coils and condensers to process heating and freezing needs, surface condensers, and more. If you need a mechanical solution, start here by looking at our entire product line. Need help selecting a descaler? We’ve outlined which descaler will best meet your needs here. Regular cleaning will keep heat exchangers operating at peak efficiency.

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