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Chapter 5: Maintenance
5.1.6 Humidifier
The steam cylinder has a limited lifetime and must be replaced periodically. Because water conditions and humidifier usage rates
vary greatly, it is difficult to establish intervals for changing the cylinder. Individual maintenance schedules must be determined for
each location, based upon periodic examination of the humidifier. A yellow LED on the humidifier control panel will flash four
times in a repeating pattern when the cylinder requires replacement.
NOTE: The yellow LED may illuminate during initial start-up, but it doesn't necessarily mean the cylinder needs to be replaced.
Refer to Section 5.3.2.1 and the humidifier operator's manual (supplied under separate cover) for detailed instructions on chang-
ing the cylinder.
Humidifier Drain Pump
The humidifier drain pump (located beneath the humidifier) should be inspected semi-annually and cleaned. The same
maintenance procedures, as detailed in Section 5.1.5, should be performed to properly maintain the humidifier drain pump.
5.2 Troubleshooting
Turn off all power to the unit before conducting any troubleshooting procedures, unless the procedure specifically requires the
system to operate. For troubleshooting purposes, the system may be operated with the doors open by using a pair of channel
lock pliers to turn the shaft of the main power disconnect switch to the "On" position. When the switch is turned on, high
voltage will be present inside the cabinet. Exercise caution to prevent injury. Keep hands, clothing, and tools clear of the electrical
terminals and rotating components. Ensure that your footing is stable at all times.
Symptom: Airflow too low.
Probable Cause: Dirty air filters (reduced airflow).
Recommendation: Clean/replace filters.
Symptom: CW valve fails to open or close.
Probable Causes/Recommendations:
a. Temperature setpoint too high. Adjust to correct temperature setting.
b. No control power to the valve. Valve actuator is wired incorrectly. Check wiring diagram and rewire if required.
c. Actuator failed. Replace actuator.
Symptom: System short of capacity.
Probable Causes/Recommendations:
a. Low airflow.
1. Check filters. Replace as needed.
2. Check for and clear any obstructions across or in the supply discharge air stream. Clear coil fins of debris.
3. Check for correct rotation of evaporator blower.
b. Low chilled water flow.
1. Check for leaks. Repair and recharge system.
2. Check for obstructions in supply/return lines.
3. Check for clogged strainer (if applicable).
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Table of Contents
Troubleshooting
