38 Maintenance
Air filter replacement
In dusty environments, the use of an air filter is strongly recommended. When used, it should be
replaced at least once a year. Do not install a wet filter on a rectifier. To remove the filter, simply
unscrew it. Install the new one by reversing the operation. Contact your local Liebert representa-
tive for ordering information on air filters.
Fan unit replacement
Visually inspect the airflow intake for any obstruction by foreign objects or excessive dust and dirt
build-up. Open both AC and DC breakers. If the rectifier is a Helios Rectifier 100/48, remove it
from the power shelf. Inspect the air outlet for obstruction by foreign objects. Visually inspect the
air outlet of the power shelf (Helios Rectifier 100/48) or the cabinet (Helios Rectifiers 200I/48 and
200E/48). The fan unit is field replaceable. Contact your local Liebert representative for ordering
information on replacement fans. To install a new fan unit, refer to the appropriate procedure and
associated figures in the maintenance chapter of the applicable rectifier user manual listed in
6.0 - Reference Documents.
If a problem is detected inside the rectifier, contact
Liebert Glo-
bal Services
at
1-800-LIEBERT.
Do not attempt to open the unit for on-site servicing.