How do I regenerate the desiccant in my EDH-4, RCD-1, or RCD-2 dehydrators?

The EDH-4, RCD-1, and RCD-2 dehydrators do not have the means to automatically regenerate their drying agent. These units use a granular desiccant consisting of Amorphous Alumina silica gel coated with an orange iron compound indicator which turns a lighter and lighter shade as it becomes more saturated. Older EDH and RCD dehydrators used a granular desiccant blend consisting of white activated alumina and blue silica gel. The blue silica gel granules turn light pink when spent to indicate the need to renew the desiccant. For the EDH model dehydrators a “renew desiccant” alarm appears when 1,000 hours has been accumulated on the pump. Normally the desiccant requires renewal every 12 to 18 months. The exact interval depends on system tightness and environmental conditions. Monthly visual inspection of the desiccant is recommended.

The desiccant bottle on the EDH–4 is accessible through the front panel. To access the desiccant, turn each of the four D-rings a quarter turn counterclockwise and remove access cover. Slide bottle forward until tubing can be removed and remove tubing before completely removing the bottle from the unit. After tubing is removed, remove the desiccant bottle from the unit and remove bottle cap. This may require some force.

The RCD model dehydrators are typically secured by Velcro, zip tie, or pipe clamp. Careful remove the tubing from the RCD end cap and detach the dehydrator. Remove the cap from the desiccant bottle. Remove grey foam filter from the bottle, taking care not to tear or otherwise damage the filter. If necessary, dry the filter. Save the filter for reinstallation.

Empty the desiccant into a clean baking dish. Heat the desiccant in a conventional oven at 250°F (121°C) for at least an hour or until the desiccant turns a dark orange; or until the pink silica gel indicator turns dark blue in older units. Do not use a microwave. Cool to room temperature. Immediately thereafter, pour the desiccant back into the bottle. Reinstall the gray filter in the top of the bottle. Reinstall the original cap. Continue reinstallation by reversing the steps you took to take the dehydrator out of service.