Causes of Evaporator Coil Leaks

If a qualified HVAC technician discovers you have low refrigerant level in your air conditioner, evaporator coil leaks are one of the likely suspects he’ll investigate.


Why Low Refrigerant Is a Problem

Low AC refrigerant can be a cause of an assortment of air conditioner efficiency and performance shortfalls, as well as triggering major malfunctions that require expensive component replacement. Frigid refrigerant circulating through the evaporator coil located in the indoor air handler extracts both heat energy and humidity from household air drawn through the ductwork by the blower fan, then transfers it outside to the condenser coil. A low refrigerant level is almost always indicative of a leak somewhere that seeps refrigerant slowly, gradually degrading system performance and efficiency.

What Causes Evaporator Coil Leaks

A typical residential A/C pushes about 1,400 cubic feet of air per minute through the evaporator coil passages. Evaporator coil leaks are common due to two causes:

  • Vibration may gradually crack brazed joints in the copper coil tubing, allowing refrigerant to escape.
  • Volatile organic compounds (VOCs) in household air formaldehyde is the most common are emitted by building materials, furniture glue, and carpeting.VOCs combine with condensation on the evaporator and react with the copper coil surfaces to form a naturally-occurring corrosive called formic acid. Inside the evaporator coil, a long-term accumulation of formic acid slowly drills minuscule pinhole leaks in the copper tubing, allow refrigerant to escape.

Steps to Prevent the Problem

Here’s how to minimize evaporator coil leaks:

  • Reduce indoor VOC levels by eliminating identifiable sources of the fumes and/or dilute indoor air with adequate fresh air ventilation.
  • Install a whole-house air purifier that incorporates a ultraviolet (UV) light array that breaks down VOCs. Whole-house units also destroy microorganisms in the air including spores, another frequent contaminator of evaporator coils.
  • Call your HVAC contractor and schedule an annual A/C maintenance check-up, including evaporator coil cleaning with solutions formulated to neutralize the accumulation of formic acid.

For more information on the causes and cures for evaporator coil leaks, contact Pioneer Comfort Services.