Aprilaire 1850 Dehumidifier User Manual


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TABLE 5 – Troubleshooting Guide
Symptom Possible Reason Troubleshooting Procedure
Dehumidifier does not
turn on/run.
No power to unit. • Checkthatthedehumidifierispluggedin.
• CheckthatthepowerswitchisturnedON.
• CheckthatthecontrolisturnedON.
• Checkthatthecircuitbreakerhasnottripped.
Dehumidifier blower is
running but with little or
no airflow.
Pressure drop across
dehumidifier is higher
than0.4”w.c.forModel
1830or0.6”w.c.for
Model 1850/1850W.
• Checkdehumidifierairfilterandwashorreplace.
• Checkforblockedductworkandclear.
• Verifythattheoutletcollarwithbackflowdamperisinstalledontheoutletsideofthedehumidifier.
• Checkifbackflowdamperisblockedorstuckandremoveobstruction.
Dehumidifier blower is
running but compressor
is not.
Float switch open. • Iffloatswitchinstalled,checkconnectionsatcontrolboardandemptycondensatepan.
• Ifnofloatswitchinstalledcheckthatthejumperisinstalledatthefloatswitchterminalsonthe
control board.
Coil frosting. • Lackoforreducedairflow.Checkdehumidifierairfilterandwashorreplace.
• Checkforblockedductwork.
• Inletairconditionsbelow60°F.Increasethehumiditysetting.
Inlet air temperature is
outside of the 50°F –
104°F range or the dew
point is below 40°F and
there is a demand for
dehumidification.
• Verifyallductworkisproperlysealed.
When zoned, the
dehumidifier damper
does not open in
INSTALLER TEST mode.
Incorrect damper wiring
or bad connection.
• Verifywiringbetweendampersand24VACtransformer.
• IfwiredforTwoZoneoperation,verifythat24VACtransformeris40VAminimum.
• Checkallwiringconnectionsbetweendampersandcontrolboard.
• VerifythenormallycloseddampersareinthePrimaryZoneductworkandthenormallyopen
dampers are in the Secondary Zone ductwork.
The ventilation damper
does not open when the
HVAC fan is active.
Cycle time has been
met.
• ThedamperwillnotopeniftheVentilationTimehasalreadybeenmet.
ODT error or outdoor air
outside of ODT range.
• CheckthattheODTiswiredcorrectlytothe
dehumidifier control board and connections are secure.
• CheckthattheODTisinstalledintheoutdoorair
intake according to the set-up specified in the
Ventilation Section beginning on page 19.
• RemovetheODTleadsfromthedehumidifiercontrol
board and check the resistance. Compare the reading
with the table shown.
Outdoor
Temperature
Resistance
0°F 84,500 Ohms
20°F 46,000 Ohms
40°F 26,000 Ohms
60°F 15,500 Ohms
80°F 9,500 Ohms
100°F 6,000 Ohms
Dehumidifier is not
draining properly.
Drain line blocked or unit
not level.
• Verifythattheunitislevel.
• Checkthedrainlineblockagesandforacontinuousdownwardslope.
The HVAC fan turns on
unexpectedly.
Dehumidifier is sampling
or ventilation in
progress.
• ThedehumidifierwillturnontheHVACfanduringairsamplingorasneededtomeettheventilation
time.
Dehumidifier is
producing hot air.
Normal function. • Airisreheatedacrossthecondensercoil,resultinginatemperaturerisebetweeninletandoutlet.
TROUBLESHOOTING (CONTINUED)
26
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