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Problems Controlling Space Humidity
Humidity too low or supply air is too cold, without optional humidifier
Possible Cause
Solution
Not enough evaporator airflow
Remove blockage in supply or return
ductwork
Check and clean filter and coil
Coil frozen – shut off unit for two hours
Defective thermal expansion valve
If under warranty call for service
If not under warranty call a refrigeration
technician
Temperature set too cold Raise temperature setpoint at thermostat
Humidity too low, without optional humidifier
Possible Cause
Solution
No moisture being added to space
Consider adding a humidifier for this space
Humidity too low with optional humidifier
Possible Cause
Solution
Humidifier not operating
Check wiring for loose, broken or frayed
connections
Check humidistat set up
Check for water flow and solenoid valve
operation
Humidifier operating
Check for proper flow
Check operations and maintenance manual of
supplied humidifier
No vapor barrier around space
Humidity too high when unit is running but not cooling
Possible Cause
Solution
Compressor not operating
Check and reset high limit switch
Clear blockage of condenser airflow
Ambient temperature is too high
Reduce temperature or draw condenser air
from another space