The A12 dew point alarm means that the internal humidity sensor is detecting moisture in the canisters. Usually, an alarm may occur for a few seconds and reset itself before it is seen as the unit determines a need to regenerate a canister.
At times with high outside humidity and duty cycles, a canister may be declared wet before the other canister has completed its regeneration cycle. At this time the unit will alarm for a dew point and then reset its self when the regenerating canister comes on line.
On dehydrators that have been in storage you may experience dew point alarms during the first 24 to 48 hours of operation due to moisture that has been absorbed into the desiccant canisters.
The humidity sensor used in the dehydrator is very sensitive and will become “saturated” at very low levels of moisture in the air. Once saturated it may take several hours of continuous dry air to dry out the sensor.
The software in the dehydrator declares a canister “wet” when the humidity sensor is “saturated” for 30 minutes of compressor run time. Given a need for several hours of continuous run time to dry out the sensor this can translate to several regeneration cycles before the sensor is dry.
A regeneration cycle for a single canister takes approximately 8 hours so you are looking at 24 to 48 hours to dry out the sensor.
Even when the canisters are declared wet the air conditioned by the canister is still dryer than the inlet air of the system.
Service will be required if the dew point alarm never clears or seems to be on without issues above being present.
In high humidity applications, a second ADH Netcom may be necessary to maintain desired waveguide humidity levels.