Verifying Capacity - Aprilaire 1710A Troubleshooting Manual

Verifying Capacity

If the unit is functioning properly, and there are no fault codes present, this procedure can be used if
there is concern that the dehumidifier is not removing sufficient moisture. After the dehumidifier
reaches stable operating conditions, measure the inlet air temperature and RH and compare it to the
outlet air temperature and RH. Use the graphs provided to convert the inlet and outlet air conditions to
air moisture content to calculate if the moisture being removed is near the performance levels shown in
the table on page 11. If the inlet air conditions are not within those listed on the table, contact Aprilaire
Technical Support Monday through Friday from 7:00 a.m. to 5:00 p.m. CST at (800) 334-6011 for
assistance in determining performance. The dehumidifier will not remove moisture if the dew point of
the inlet air is 40°F or lower.
1. Verify that the flap damper on the outlet of the dehumidifier opens/closes freely.
2. Verify that the ductwork is free of obstructions and kinks and that the filter is clean – remove
the filter for this test if dirty.
3. Ensure the front and back panels are in place and assembled with screws. DO NOT REMOVE
PANELS DURING THIS TEST.
4. Remove the control door. Disconnect all electrical connections to the HVAC equipment by
removing the HVAC Equipment terminal block from the control board. Disconnect any remote
control by removing the REMOTE terminal block.
5. Move the LOCAL/EXTERNAL dip switch on the control board to LOCAL
6. Replace the control door.
7. Adjust the control knob to the highest setting – 7 (do not put the unit in TEST mode as this will
allow the compressor to run for only one minute) to initiate a dehumidifier call. Note: If the
dew point of the air is below 40°F, the dehumidifier compressor will not turn on.
8. Remove one of the filter doors and insert a temperature/humidity measuring instrument in
front of the filter/coil. Close the filter door as much as possible during the reading.
9. Allow time for the measuring instrument to get a good, stable reading.
10. Record the dry-bulb temperature and RH of the inlet air.
11. Find the inlet air moisture content in the graph appropriate for the model being tested below.
Locate the inlet air temperature at the bottom of the graph and draw a straight line up until you
meet the inlet air RH curve then read the moisture content at the left (360 PPD @ 80°, 60% RH
for Model 1710A/1750A example shown).
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