Chapter 6 System O&M 53
Liebert_DM 16kW Air Conditioner User Manual
plate in front of the humidifier before you can reach the plugs. The plugs of the double-door and triple-door systems
are located to the left of the humidifier and are accessible directly.
3. After draining the water in the water pan, remove the drainage pipe, remove the fixing screws on both sides of the
humidifier, and then pull out the humidifier.
4. Open the cover plate (for single-door system, this cover plate has been opened in step two) to reveal the ceramic
socket. Use the multimeter to locate the burned lamp.
5. Remove the humidifier water pan.
6. Remove the brackets in the middle that support the lamps.
Infrared lamp
Ceramic socket
Lamp supporting bracket
Fixing screw of
ceramic socket
Fixing screw of wires
Lamp supporting bracket
Figure 6-3 Lamps of infrared humidifier
7. Remove the screws that fix the cables of the lamp to be replaced from the ceramic sockets (note to hold the lamp
with hand).
8. Pull down the lamp.
9. Install a new lamp.
Note
Do not touch the quartz lamp with bare hands! Greasy sediment and finger prints can seriously shorten the life span of quartz
lamps. Therefore, put on clean cotton gloves during the operation.
10. Restore the humidifier by reversing steps 3 ~ 8.
Autoflush system of the infrared humidifier
Note
The normal operation of the autoflush system, the humidifier demands a water source with minimum water flow of 1gpm (0.063
l/s) and minimum pressure of 20 psig (138kPa).
Operation of the autoflush
The autoflush control program is an integral part of the infrared humidifier system. The program automatically controls
a water makeup valve to maintain the proper water level in the humidifier pan during operation. When a call for
humidification exists, the program performs a series of checks.
The first check is to see how long the infrared humidifier has been off. If the off time is equal to or greater than the
programmed value (factory default is 15hr), it is assumed that the pan is dry and a program called pre-fill is initiated to
add water to the pan. During the pre-fill operation the infrared lamps are inactive. The pre-fill time is programmable
with an adjustable range of 1 ~ 120s for either pan size. The factory default for a large pan is 60s and for a small pan is
30s.
If the off time is less than 15hr (or user programmed value) the pre-fill program is bypassed and the infrared lamps and
water valve are activated at the same time to fill the pan to the proper water level and initiate humidification.
During normal infrared humidification operation the water makeup valve is periodically closed (no pan fill) and opened
(pan fill) based on a timing sequence to allow for the evaporation of water from the pan.
With the humidifier water flush rate set at the factory default value of 150% the water makeup valve will open for 7min
of till time with an off time of 45s between fill cycles for a small pan. For a large pan water makeup valve will open for
10min of fill time with an off time of 80s between fill cycles. You can modify the percentage from 110% to a maximum
of 500% in 1% increments. See Figure 6-4 for humidification control logic.
