If your swamp cooler runs out of water, it won't cause immediate catastrophic damage, but it will stop cooling and can cause problems if the condition persists.
Immediate effects:
- No cooling - Without water, there's no evaporation, so no cooling effect
- Just a fan - The unit becomes an expensive fan, blowing hot outside air into your home
- Dry pads - The cooling pads will dry out
Short-term concerns:
Running briefly without water (under an hour) typically causes no damage. The unit simply operates as a fan. However, you're wasting electricity without getting cooling benefit.
Longer-term problems:
If the cooler runs dry repeatedly or for extended periods:
1. Pump damage
- The water pump can overheat when running dry
- Pump bearings may wear prematurely
- Some pumps have thermal protection; others don't
2. Pad deterioration
- Aspen pads can become brittle when repeatedly dried
- Minerals concentrate and harden on dry pads
- Rigid media pads handle dry periods better
3. Motor stress
- Without the cooling effect of moist air, motors run hotter
- Generally not a major concern for short periods
Why it might run dry:
- Float valve stuck or broken - Most common cause
- Water supply turned off - Check the valve
- Clogged water line - Mineral deposits can block flow
- Low water pressure - May not fill fast enough
- Leak in the reservoir - Water drains before it can accumulate
Prevention:
- Check water flow weekly during cooling season
- Listen for the pump running (if it's running but pads are dry, there's a distribution problem)
- Inspect the float valve at season start
- Most modern units have low-water shutoffs—consider upgrading if yours doesn't
What to do if it happens:
1. Turn off the cooler 2. Check water supply and float valve 3. Wait for water to fill the reservoir 4. Restart and verify pads are getting wet 5. If the pump makes grinding noises, it may need replacement