Microchannel coils also tend to be slightly easier to clean than traditional copper tube/aluminum finned condensers. Their reduced depth and parallel tube layout minimize the restriction of cleaning water as it travels through the condenser. This provides a shorter and more direct path for cleaning water to effectively carry away dirt and debris. The best practice when cleaning these coils is to remove any loose debris first with a soft brush or vacuum cleaner. Be careful not to damage the coil during this step. Avoid using any hard objects that can cause damage to the coil.  

Next, rinse the coil with water. Avoid using too high of a water pressure as these coils can also be damaged if the pressure is too high. If needed, spray on a chemical cleaner to saturate the coil — follow the directions supplied with the chemical cleaner. It is especially important to use only an approved chemical. Due to its all-aluminum design, do not use any cleaners that are caustic or have an acidic base, as they can damage these coils. 

After allowing the chemical to thoroughly break down the dirt, rinse with water to remove the coil chemical and any debris. Due to its geometric design, water may pool on the coil. To remove this water, try using some compressed air, a vacuum, or allowing the condenser fan to run without the compressor operating.  

Leak Repair 

Repairing leaks on these coils will be different from traditional coils. One method is to use a low-temperature aluminum solder alloy. This is a much lower temperature process compared to brazing an all-copper joint. Extreme care must be taken while heating the aluminum surface, as applying too much heat could melt down the area and possibly make the leak unrepairable. There are kits with detailed instructions available for this process.  

Another method is to use an epoxy. Again, simply follow the directions to use this method. This process is generally safer but is more time-consuming. Pulling a vacuum on the condenser during the repair can help draw the epoxy into the leaking section and allow for a better seal.  

Microchannel condensers have many advantages; however, the tiny channels that make them more efficient are also easier to plug from contaminants entering the system as a result of poor service practices. Be sure to: 

• Keep shavings out of the system when cutting and reaming; 

• Flow nitrogen while brazing; 

• Install a new liquid line drier after making a refrigerant repair; and  

• Pull a proper vacuum. 

All of these practices — which have been standard for many years — become more important when the system uses a microchannel condenser.