When this occurs the wheel and housing should be cleaned to assure smooth and safe operation. Inspect fan impeller and housing for fatigue, corrosion or wear. Routinely check all fasteners, set screws and locking collars on the fan, bearings, drive, motor base and accessories for tightness. A proper maintenance program will help preserve the performance and reliability designed into the fan. Deflection = Belt Span Belt Span 64 FIGURE 18 VIBRATION Excessive vibration maybe experienced during init

**IMPORTANT** ALL FACTORY PROVIDED LIFTING LUGS MUST BE USED WHEN LIFTING THE UNITS. FAILURE TO COMPLY WITH THIS SAFETY PRECAUTION COULD RESULT IN PROPERTY DAMAGE, SERIOUS INJURY OR DEATH. Models: HRE-20, 45, 55, & 90 INSTALLATION, OPERATION AND MAINTENANCE MANUAL Direct Evaporative Cooler (Outdoor/Supply Airstream) Indirect Evaporative Cooler (Exhaust/Scavenger Airstream) TABLE OF CONTENTS Storage . . . . . . . . . . . . . . . . . . . . . . . . . .2 Economizer Application/Operation . . .14 Gene

If there are deposits, the bleed-off rate needs to be increased. Some areas of the country have water with greater amounts of dissolved minerals requiring a higher bleed-off rate. Unit Size Media Pad Top Area HRE-20 1.5 ft2 HRE-45 2 ft2 HRE-55 2.5 ft2 HRE-90 3.3 ft2 8. Verify that both airflow and system static pressure are in agreement with the specifications. If these conditions are met, check for water carry over from the discharge side of the media. If carry over is observed, check the distr

FROST CONTROL APPLICATION/OPERATION When outdoor air temperatures are extremely cold, moisture condensation and frosting on the energy recovery wheel is possible. Frost control is an optional feature that will prevent wheel frosting. Two options are available: 1) Timed Exhaust frost control and 2) Preheat frost control Timed exhaust frost control includes a thermostat (with probe) mounted in the supply air inlet compartment (see FIGURE 13, page 14) and a timer (Figure 12) mounted in the HRE cont