Abstract: A unit for prevention clogging in condensate drain pans by discharging an anti-bacterial chemical into the drain pan to prevent slime accumulation is provided. The anti-bacterial chemical comprises of a first low-soluble anti-bacterial compound and a second readily soluble compound having a higher solubility that the first low soluble anti-bacterial compound. The device is provided with a novel cap having metering orifices for effecting a controlled diffusion rate of anti-bacterial chemicals into a drain pan and further including projections for spacing the metering orifices away from a surface, the spacing in combination with the metering orifices and solubility characteristic of the anti-bacterial chemical effecting a capillary action to introduce the anti-bacterial chemical through the orifice into contact with the condensate at a controlled rate.