The reliability and thermal performance of any ACHE depends on how well its mechanical components are maintained. The components of ACHEs are fairly common; typically each bay has one, two, or three electric-motor-driven fans. Most have a speed reducer consisting of either a belt drive (e.g., V-belt or cog belt) or right-angle gear drive. A belt-drive system has four bearings that need to be lubricated — two motor bearings and two fan bearings for each fan. These are typically tubed to a common location somewhere on the drive assembly so they can be lubricated while the exchanger is running. Manufacturers usually recommend that you grease the bearings once a month if the coolers are in continuous operation. Right-angle gear drives should be lubricated according to the manufacturer’s recommendations. Check belt tension on a regular basis, usually every six weeks at a minimum for ACHEs that are in continuous service. Check belts for wear, and sprockets for tooth wear or cracking. Inspect fans at least annually by following these procedures (4):
