Keep clear of standing water near the equipment or any outlet, and switch the system off at the thermostat if water is spreading.
Where the water comes from
Warm, humid air condenses on the cold indoor coil the way water beads on a cold glass. It drips into a pan under the coil and runs out through a drain line to the outside, a floor drain or a small pump.
Algae, sludge and debris build up in that line over time. When it clogs, the pan fills and overflows.
Likely causes
- A condensate drain line blocked by algae or debris
- A drain pan that has cracked or rusted through
- A condensate pump that has failed
- A frozen coil that is thawing and releasing more water than the pan can handle
Leave the float switch alone
Many systems have a float switch in the pan or drain line that shuts the cooling off when water rises. If the system has stopped and the pan is full, that switch is doing its job and holding back an overflow. Leave it in place rather than bypassing it to get cooling back.
When professional help makes sense
Clearing the drain line, replacing a failed pump or pan, and finding out why a coil froze are all routine work. Water that reaches ceilings, floors or electrical parts is worth dealing with as soon as it is found.