Premature Coil Failure in Ductless Mini-Splits & VRF Equipment – Short #303

In this short podcast, Bryan and Roman discuss premature coil failure in ductless mini-splits and VRF equipment.

These coils are susceptible to a few different types of corrosion. Warmer coil saturation temperatures and shorter runtimes result in lower latent capacity; whatever moisture is on the coil dries on the coil instead of draining out. Minerals and chemicals (including chlorides from bleach or cleaners) interact with the coil and may cause corrosion, including formicary (“ant’s nest”) corrosion. Leaks and corrosion may be environmental rather than entirely attributable to manufacturer defects.

Technicians can use proper cleaners with correct dilution ratios and rinse the coils. In situations where the environment contributes to coil corrosion, such as with substances off-gassing or dealing with coastal air, we will need to dilute the pollutants by ensuring proper ventilation. Dilution needs to be intentional, especially in hot-humid climates, and ventilating dehumidifiers with good filtration may be a good move. Source control and filtration are also good mitigation strategies, and clear, open client communication can help clients understand the problem and make informed decisions about their HVAC system.

This episode contains embedded sponsor messages from Refrigeration Technologies, Carrier, NAVAC, and Fieldpiece.

Resources

• Coil Corrosion w/ Kevin Hart and Bryan Orr
• Living in a World of Acids (and why HVAC coils are secretly crying for help)
• HVAC School calculators
• Submit a podcast question
• Learn about the GRIT Foundation

Purchase your tickets or learn more about the 8th Annual HVACR Training Symposium at https://www.hvacrschool.com/symposium.