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Swamp cooler care, season by season

Evaporative coolers are common across the Imperial Valley because they cool well in dry heat for much less electricity than central AC. They need hands-on care twice a year and a check mid-season.

Safety first: turn off the power at the breaker and the water supply before working on a cooler, and use a secure ladder for roof units. If you're not comfortable on the roof, have a pro do it.

Spring startup (around April)

Remove the cover and side panels.
Drain any standing water and scrub the pan to remove mineral scale.
Replace the pads, or clean them if they're rigid media in good condition.
Check the pump and clean its intake screen.
Check the float valve so the pan fills to the right level without overflowing.
Inspect the belt (if your cooler has one) for cracks and proper tension.
Reconnect the water line, restore power, and run it to check that the pads soak evenly.

Summer upkeep

Look at the pads monthly. White crust means minerals are building up.
Valley water is hard, so many homes need a second pad change by midsummer.
Open a window or two a few inches. Swamp coolers need an exit path for air.
When humidity rises in late summer, switch to central AC if you have it.

Fall shutdown (October)

Turn off the water and drain the pan and lines.
Clean the pan and let it dry.
Unplug or switch off the power.
Cover the unit outside and close the indoor vent to stop drafts and dust.