Evaporative Coolers - Suggested Maintenance version 9/10/01
1. Start of Season - At the start of hot weather:
Uncover. Remove weather protective cover, if any. Put in proper storage.
Unique Identification. If there are several evaporative cooler units serving the building, check that the unit is labeled with the unit's unique identification, such as EC-1, EC-2, North unit, etc. If unit needs a unique identification, initiate project to have it identified and labeled. (Identification should match interior electrical panel's circuit card description.)
Power Disconnect. Shut off power to the unit at the external local disconnect. If no external local disconnect exists, initiate project to have one installed.
Access Panel. Remove preferred access panel. If preferred access panel is not identified, determine the access panel that is best for servicing, identify it with marker pen, and initiate project to have a permanent tag installed on that panel, for example "SERVICE ACCESS HERE".
Media. Inspect condition of the media. Replace media that is excessively damaged or deteriorated, has holes or rips in it, or has excessive buildup of mineral scale. Media that is too thin or with large air spaces should be replaced with thicker or denser pads. Check that media is mounted correctly, it may have been moved out of its correct mounting position by the winter weather.
Belt. Inspect condition of the belt between the motor and the fan. Replace if necessary. Check tightness.
Drive Components. Check that all drive components appear to be in good condition, with nothing loose or missing, including shafts, keys, set screws, collars, bearings, pulleys, motor mountings, nuts and bolts.
Oil the Motor.
Oil the fan shaft bearings.
Electrical Connections. Be sure power to the unit is disconnected. Check that all electrical connections are tight.
Water Supply. Open the water supply valve. (It should have been shut for the winter.)
Float Valve. Test operation of the float valve. Repair or replace if necessary. Systems that work on continuous running water without a float valve are water wasters, initiate a project to upgrade such systems.
Sump. Clean the sump. Fill sump and check that it is leaktight. Repair if possible. If not possible to repair a leaking sump, unit may cause water damage to the building. Initiate project to have sump or entire evaporative cooler replaced.
Sump Pump Strainer. Clean sump pump strainer. Check that sump pump strainer has no rips or holes, and is mounted correctly. If no sump pump strainer exists, initiate project to have one installed.
Sump Overflow. Force float valve open and observe proper overflow drainage. If overflow drain is clogged or damaged, repair as necessary. Overflow should be captured completely and drain to an acceptable location. If overflow design is unsatisfactory, initiate project to correct overflow design.
Air Isolation. Open air isolation damper, if any. (Often called a damper slide.) Unit should have been isolated from ducting and the occupancy during the winter. If no isolation damper exists, initiate project to have one installed.
Power Up. Danger - moving pulleys, moving belt and live electrical points! Be careful. Power up the unit with the access panel open, and observe operation of the unit for several minutes.
Fan Wheel Vibration. If fan wheel is vibrating or bouncing, and the belt was adjusted to proper tightness, then the fan wheel shaft bearings may be worn out. If so, then replace the bearings.
Pump operation. Pump should be pumping a sufficient amount of water, and be operating without excessive vibration or noise. Replace pump if not operating well.
Pump low water cutoff. If pump has a low water cutoff control (usually a float), test that forcing the control does shut the pump.
Freeze Control. Maintenance on freeze controls is probably not necessary.
Water Distribution. With unit powered up, observe the water distribution. It should be dripping onto the media equally at all points. If water distribution is not equally distributed, note the problems, shut the power, and repair as necessary. Distribution tubing may have moved, be damaged, or be clogged. Water distribution structures (sometimes known as "galleries') may be damaged or deteriorated, clogged with mineral build-up or debris, or not level. Clear clogged holes with a scribe or ice pick, level the galleries or whole unit with shims. It is important to repair these problems. Lack of water on any of the media defeats the principle of evaporative cooling, allowing hot air to pass through to the occupants.
Water Bleed. Check that the water bleed system is actually working, that a fraction of the pumped water goes through a bleed valve and is properly drained (not returned to the sump). Bleed valve should be easy to access without reaching near the pulleys or belt, and flow out of the bleed should be through open air where it is easy to see. If no such system exists, initiate a project to have one installed.
Final Operation Test. Replace access panel(s) and observe operation. All media pads should be wetted equally. If media pads are pulling into the unit due to negative pressure, the racks supporting the media pads may need repair, or more rack structure may be needed. Repair or initiate project to increase rack structure.
Drainage and Leakage. Any leakage onto the roof is not acceptable. If unit is causing water to get on roof, investigate the cause and repair, or write trouble ticket to repair. Drains should be in PVC pipe to the nearest roof drain, roof edge gutter, or over the roof edge.
Painting. Assess whether unit needs painting, and whether it needs full painting or just touch-up, and whether on interior, exterior or both. Paint as necessary, or initiate a project to have unit painted.
2. Mid-Season Maintenance - Middle of Summer:
Visit the unit while it is operating.
Check for obvious problems. Check that the fan is operating and that the pump is operating. Repair any obvious problem. Troubleshoot any excessive noise or vibration.
Water Leaks. Repair any water leaks. Roof should be dry.
Media. Check that the media is being wetted evenly and equally. Repair if necessary.
Bleed. Check that the bleed is operating. Reduce bleed if media show zero mineral build-up. Increase bleed if media show excessive mineral build-up.
Oil the motor, only if necessary.
Oil the fan bearings, only if necessary.
Sump. Clean the sump, if necessary. Clean the sump strainer, if necessary. If sump has excessive dirt or biological growth at mid season, the unit needs maintenance more often.
3. End of Season Maintenance - After the end of hot weather:
Shut the electrical disconnect.
Shut the water supply.
Drain all water out of the unit, and drain all piping.
Freezing. Assess whether any part of the unit, or any water piping outside the unit is subject to freeze damage. Consider pockets where water cannot drain, and uninsulated piping that will have water in it during the winter. Take necessary action to prevent freeze damage.
Air Isolation. Shut air isolation damper, if any. (Often called a damper slide.) Unit should be isolated from ducting and the occupancy during the winter. If no isolation damper exists, initiate project to have one installed.
Cover the unit, if a protective cover is available.
home news other