Aprilaire 1710A Troubleshooting Manual page 6

degrees (10°) or more. If the inlet air temperature is cold (i.e. around 60°F or lower)
the drop may be slightly less than 10°F, but should be more than 5°.
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5 blinks The temperature of the incoming air is less than 50°F or is higher than 100°F when the
compressor is attempting to start. The most likely cause for this failure mode is that the
dehumidifier is installed in an application with temperatures outside of the specification for
this product or there are leaks in the ductwork causing temperature extremes at the
dehumidifier inlet.
1. Turn the ON/OFF switch OFF and to reset the failure.
2. Consider the following for the application:

All installations – If ducting to the HVAC system, make sure the inlet to the dehumidifier
is not ducted to the supply side of the HVAC system.

Attic installations – Inspect the ductwork attached to the inlet of the dehumidifier for
leaks if the ambient temperature is high.
This error code registers differently depending on the control board and method of
control. See below for sequence of operation and troubleshooting.
Old Control Board with External Control
- The inlet air is sampled immediately. If the inlet air is above 105° the 5 flash error
code will be displayed and will remain until power is cycled to the unit.
- After resetting the fault by cycling power to the unit, inspect the ductwork for leaks
on the inlet side or blockage on the outlet side. If there are no problems found with
the ductwork and the error persists, replace the old control board with a new control
board.
New Control Board with External Control
- Regardless of inlet temperature, the blower and compressor will turn on for 3
minutes. If the inlet air temperature is above 105° after 3 minutes, the 5 flash error
code will be displayed and the blower and compressor will turn off. The fault will
self-correct if the temperature drops below 105°.
- The blower and compressor will remain off for 3 minutes and then turn on and
remain on for 3 minutes. This cycle will continue (3 minutes on and 3 minutes off) as
long as there is dehumidification demand from the external control and the inlet
temperature remains above 105°F.
- If the inlet temperature is above 105° after 3 minutes check for duct leakage on the
inlet side and duct blockage on the outlet side.
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If there is no temperature drop (no voltage increase) then there is likely a
refrigerant leak and the unit will need to be replaced.
If there is a temperature drop, but not as much as expected, allow the
compressor to continue to run an additional 10 minutes and check again.
If the temperature drop is 10° or more, then continue on to "Verifying Capacity"
on page 8 to determine the actual performance.