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UV air filters and drain pans

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Question:
Do you think there is  any problem with ultraviolet furnace filters as far  as it depleting the inside of the Duct liner or plastic or rubber that the ultraviolet rays bounce off.

It depends on the type of plastic your condensate pan is made of.  Some of the newer drain pans are UV resistant but you would have to check with the manufacturer to know for sure.  UV also causes rubber to deteriorate.

There are a few of things you can do to avoid this potential problem.

– Install the UV air cleaner in the return duct before the ac unit.  This way the light doesn’t contact the drain pan or any other plastic parts.

– Mount it in the supply duct far enough away so that it doesn’t contact the drain pan or any other plastic parts.

– Place a shade of some sort above the condensate pan to prevent the UV rays from contacting the drain pan.  You have to be careful not to do anything that can potentially affect air flow.

What I recommend is that you install the uv air cleaner in the supply air duct.  This will treat the air before it enters your living space and destroy most mold spores, bacteria, viruses and other pathogens.

I often read that UV lights should also shine on the evaporator coil to destroy any mold that may grow there.  I have worked on thousands of air conditioners and have seen very few with mold growing on an evaporator coil.  I have seen many dirty evaporator coils but that doesn’t mean there is mold.



I have seen condensate pans, drain lines and p-traps with some nasty looking things growing in them that I handle carefully.  The reason things grow in these places is because a lot of contaminants from the air collects there.  The evaporator coil is wet from condensation most of the time and as air passes through the evaporator coil, contaminants collect on the coil and many of these contaminants are washed away with the moisture on the coil as it drains off.  So the coil actually stays fairly clean for a long time when using efficient furnace filters and a lot of the contaminants collect in the drain pan, drain line and p-trap.  You can treat these components with a mixture of bleach and water, about 10 parts water to 1 part bleach.

If, for some reason you are having problems with mold on the evaporator coil contact your service technician and have him or her clean the coil with one of the many chemicals available.  There are environmentally friendlier cleaners available also.

Regarding the duct liner, I don’t think UV light would have any effect on it.

Best,

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P.S. I submitted this question (Do uv lamps damage plastic condensate pans and rubber?) to a popular UV air cleaner manufacturer and below is the reply that I received.

This depends on if it is plastic or rubber not rated for UV exposure.  The only rubber we know of that is affected by UV light is rubber manufactured in China, where a different formula is used in their mix.  As for plastics, Schedule 40 and SDR 35 PVC is affected (usually used for plumbing / sewer drainage).  PVC will brown, like a paper plate left in the sun all summer.  Wires (electrical) are not affected by direct exposure to UV light except old wires used prior to 1965 that used a different jacket than what is used today.


About the author: Don has been working in the HVAC industry for more than 25 years and shares his experience and knowledge on this site. If you find the information presented here helpful please share with your friends.

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