A frequent failure on reach-in coolers is a loss of refrigerant. Although the refrigerant leak can be anywhere within the system, a common location is in the evaporator coil. When this repair arises, a decision needs to be made whether to attempt to repair the coil or replace it.
Repairing a leak on an evaporator coil is not always possible, and it does come with a risk. However, replacing the evaporator coil is expensive, and on older coolers, it might not be possible to get the original coil. Another option is to replace the entire unit, which is the most expensive option, but depending on the overall condition of the case, it might be the preferred solution.
Before beginning any repair, have a discussion with the equipment owner to lay out the options and help them decide their best solution. Sometimes it is not about the cheapest repair but the best and most reliable long-term solution for their business.
When deciding whether to attempt a repair on a coil, here are a few items to consider. First, where is the leak? Is it on a return bend, on the tubing passing through a tube sheet, or within the finned section of the coil? Leaks on a return bend are easier to repair. Leaks close to the tube sheets or within the finned section might be possible but require cutting away the metal. Depending on where the leak is located, it may be extremely difficult to repair or not even possible.
Second, will heating the coil cause further damage and make the repair impossible or impractical? Evaporator coils are generally made with thinner-walled tubing than the ACR tubing connecting the evaporator to the rest of the system. If too much heat is applied to the evaporator, it could burn through the section being repaired, or it could make the hole larger, thus making the repair impossible or impractical.
Third, if repairing the evaporator coil is possible, will another leak develop? This could require repairing the evaporator a second time or even replacing it. This could lead to an uncomfortable conversation between the technician and the customer, who may not be happy about paying for another expensive repair after spending money on the first repair.
When replacing an evaporator coil, using an OEM replacement is preferred, but if that option is unavailable, a similar coil with the same Btu rating, physical size, and configuration might be an option. Another option is to replace the entire evaporator assembly, which includes not only the coil but also its housing and fan. Again, technicians need to match its Btu capacity and physical dimensions. Matching up a non-OEM replacement can be challenging and not always possible, but the extra effort required might be a better option than trying to repair the original coil.
Over the years, I have generally found that it is better to replace an evaporator coil rather than attempt a repair. It is more reliable and the best long-term solution for a customer.