87
VAPOR-LOGIC
®
VERSION 6 INSTALLATION AND OPERATION MANUAL
Troubleshooting guide
Table 87-1:
Troubleshooting guide (continued)
Humidity set point issues
Issue
Possible causes
Actions
Humidity is below desired
level
• Unit is operating but fails to meet required
humidity level
• Unit undersized; replace with a larger unit or add additional
humidifier .
• Skim duration is too long .
• If drain valve does not close fully, determine the cause and
clean, repair, or replace as needed .
• If drain pipe water seal is allowing steam to go down the
drain, fill P-trap with water or repair as needed .
• If there is an improper water seal height, increase to the
recommended height (see humidifier tank manual for water
seal height) .
• If there is excessive internal steam pressure, determine the
cause of the high pressure (e .g ., high duct static pressure,
undersized orifices in dispersion tubes, water, or crushed
vapor hose) and correct as required .
• Replace leaking gasket or vapor hose .
• Recalibrate if controls are out of calibration .
• If fill valve is stuck open, repair or replace .
• If zone valve will not open, repair or replace .
• Interconnecting steam piping to the dispersion assembly is too
long and/or uninsulated (do not insulate steam hose) .
• No call for humidity from humidistat or from
control and high limit humidity transmitters
• Low or no signal strength from humidistat . Check for proper
wiring .
• Check humidity transmitters (4 to 20 mA output) .
• Adjust set point if RH or dew point set point is too low .
• Excessive outside air volume
• Verify proper operation of fans, dampers, VAV systems, etc .
• Humidity control input type not the same as
Vapor-logic
firmware
• Check Vapor-logic
control board connections P11 and P13 .
Consult DriSteem .
• Vapor-logic
not in Auto mode
• Change mode to Auto .
Continued
TROUBLESHOOTING
