Manualshelf

Troubleshooting Guide

ManualsBrandsAprilaire ManualsDehumidifiersDehumidifier with Automatic Digital Control, Hard Wired (130 Pints Per Day)
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1. Use the color of the wire connected to the A, B, + and – (on the Model 76, the “+” and “-“
terminals are labeled “R/+” and “C/-“) terminals on both the base of the Model 76 and
the dehumidifier User Interface Assembly to verify that they are wired correctly. Make
sure the terminal screws on both the User Interface Assembly and the Model 76 base are
tight.
2. Remove the Remote terminal block from the User Interface Assembly and measure the
DC voltage across the + and – pins on the User Interface Assembly – this should read
approximately 35 V DC (±3V for voltage variation and load). If there is 0 volts, the User
Interface Assembly (5445) must be replaced. If in range, reinstall the Remote terminal
block.
3. If connections are correct and secure, turn off the dehumidifier and remove the Model
76 control. Use a short section of 4-wire cable to reconnect the Model 76 to the User
Interface Assembly to see if there is a problem with the existing wire. Turn the
dehumidifier back on. If the “E3” code continues, the Model 76 must be replaced, if the
code is gone, then the wire between the Model 76 and the dehumidifier must be
replaced.
E4 – Insufficient Capacity: The temperature of the suction line, as sensed by the Frost Sensor, has not
dropped at least 5°F in 20 minutes from the temperature it was when the compressor
started. One reason this would happen is if the dehumidifier went from a cold condition to a
warm condition very quickly (e.g. coming off a cold truck into a warm home) AND there was
little airflow through the unit prior to the compressor starting. If this is possibly the case,
then allow the dehumidifier to acclimate to the conditions for one hour before restarting.
The E4 code on the internal board was revised 282014AXXXXX. Reprogrammed boards were
labeled V1.4 and boards from the supplier with the change were labeled V1.2. Anything
higher than V1.1 has the E4 fix.
Other reasons this code would be displayed is if the compressor is not running or if the
refrigeration system is not operating properly.