If your swamp cooler is blowing warm air on a "cool" setting, or it isn't working at all, even with a good cord and outlet, try replacing the water pump. The pump sends the water over a filter, which transmits the air through duct work. You should be able to replace a swamp cooler pump yourself with no HVAC experience. Here are some tips to replace a swamp cooler pump.

Prepare to Work

For this project, you need:

  • Phillips screwdriver and flathead screwdriver
  • pliers
  • mild detergent
  • soft brush
  • lubricant
  • old towel
  • replacement pads and belts (optional)
  • replacement water pump system with mesh filter bag or basket

Unplug the swamp cooler. Loosen the screws on the side panels, and put the panel aside. Look for the pump at the bottom and detach the wires.

Before you replace the pump, check the screen for debris and wipe it clean with mild detergent and a bristle brush. Install the panels and test the unit again. If cleaning doesn't help, replace the pump.

Remove the Old Pump

Detach the hose clamp from the hose by pressing the sides with pliers and remove the hose. Some hoses may be removed by pushing them over a barbed fitting.

If there is a bleed line, disconnect it from the bleed tee. A bleed line is a one-fourth inch flexible tube connected to the overflow tube.

Install the New Pump

Set the new pump in the water reservoir, preferably inside a mesh bag or basket. The mesh bag or basket will prevent.scale formation on the new pump. Use the pliers to secure the brackets on the pump.

Make a pencil mark about a couple of inches from the hose clamp ends and install a hose ring clamp on the marks. Fasten the bleed tee to the pump hose and reinstall the bleed tee line.

Attach the other end of the hose to the water distributor above the pads. Press the clamps until they come to within one-half inch on the end of the hose and tighten the clamps.

Before you reattach the panels, inspect the drive belt and cooler pads for damage and replace them, if needed.

Check the tension on the belt. Empty the water tray, then clean it with mild detergent and a soft -bristle brush. Dry the tray with an old towel. 

Put all the parts back in place, restore power, and test the unit. If the swamp cooler still doesn't work, or you don't trust your skill, contact an air conditioning repair service like McKinney Heating & Air Conditioning.