Ultraviolet Light

[jkendzio]

Having a mildew problem in my air handler. What size/type/model of ultraviolet light is typically placed within the air hanldler to prevent the growth of mildew/mold and are they placed below or above the evaparator? thanks.

 

[Ralphs1]

1st you need to find out why you have mold.
A/C incorrectly sized or set up wrong is common.

I am not a expert but they are sized based on CFM of air flow.
They also can be installed return only, supply only or both.
Near the evap coil is good due to the moisture can feed the mold. UV lite can damage some plastics that come in direct contact.
Hope this helps.

 

[stanlsimon]

Micro organisms need three things to proliferate: Moisture, the correct temperature range and something to feed upon, generally some organic material.

Condensate control from cooling coils is required. Make sure your face air velocity is below 550 fpm absolute maximum or preferably less than 500. Otherwise condensate will blow off the cooling coil. Also check for air bypass around the bottom of the coil that could aspirate condensate.

For a draw through air handler make sure that there is a properly configured trap in the condensate drain that allows the condensate to work it's way out against the negative pressure.

Rough surfaces such as fiberglass insulation tend to accumulate dust and dirt which in turn will provide a breeding ground for fungus. Smooth surfaces are much better.
Silver containing alloys are available, the silver kills microorganisms.

There is no substitute for a duct cleaning program that includes cleaning of air handlers.

 

[MintJulep]

You might like to read this:

thread403-143390

 

[RossABQ]

There are useful in evaporative cooler sections of AHU's. Since these areas are wet by design and biocides are frowned upon, they are useful in keeping bacterial growth on the media in check. Penetration into deep media isn't a given, though. The make-up water used for the cooler is also UV'd just ahead of the unit (reverse osmosis quality water is used in many systems). These are relatively high-end AHU's (semiconductor fab support areas).