88
VAPOR-LOGIC
®
VERSION 6 INSTALLATION AND OPERATION MANUAL
Table 88-1:
Troubleshooting guide (continued)
Humidity set point issues
Issue Possible causes Actions
Humidity above set point • High entering relative humidity • Dehumidify.
• Unit oversized • Consult DriSteem.
• Reduced airflow • Check fans, dampers, VAV systems, etc.
• Improperly located humidistat or humidity
transmitters
• Relocate, using guidelines in Appendix section of this manual.
• Malfunctioning controls • Check for incorrect supply voltage.
• Check for incorrect control signal.
• Check for improper wiring hookup.
• If humidity controller or transmitter are out of calibration or
malfunctioning, repair or recalibrate.
Hunting (humidity swings
above and below desired set
point)
• Malfunctioning control system • If there is a faulty or inaccurate humidity controller or
transmitter, repair or replace.
• Check for proper Vapor-logic
control settings: RH set point,
high limit set point, cycle rate, PID tuning, etc.
• Relocate poorly located control components. See “Sensor
placement” on Page 26.
• Verify that the touchscreen display modular cable is isolated
from power wiring.
• Air volume varies rapidly • Stabilize.
• Air temperature is varying rapidly • Stabilize to ±1 ºF (±1 ºC).
• Proportional band is too small and/or
integral gain (Ki) is too large
• If RH swings outside PID band, increase PID band using the
Settings menu.
• Decrease integral gain (Ki) using the Set Up menu.
• On-off control is not adequate • If controlling the humidifier with an on-off signal, consider
changing to controlling with a modulating signal.
Continued
Troubleshooting guide
TROUBLESHOOTING
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