Filter full and blocked intake signals

A filter or flow warning means the robot thinks water isn't moving through it as it should. The usual reason is plain. The filter is full, or something is blocking the way in.

That's good news, because it's a job you can do at the pool edge in a few minutes.

What the robot is checking

A pool robot pulls water in at the intake, through the filter, and out again. If the filter packs up, the flow drops.

One maker's support page puts it this way: when the filter is saturated, suction flow drops and many robots trigger an automatic protection shutdown¹. So a filter light isn't always a sensor reading the filter. It may be the robot noticing weak flow.

Some robots have a dedicated filter light. Others fold this into a general warning or a power-supply blink. Your manual's table tells you which yours does.

Other things that look like a full filter

Don't stop at the basket. A blocked intake or stuck propeller gives a similar result.

One troubleshooting list covers a power supply with every LED blinking. Its checks: is the unit out of water, is the filter bag stuck in the screen, are the propellers stuck².

Another maker's page lists a clogged suction mouth and a jammed impeller beside a full debris compartment as causes of slow or no movement³.

For the impeller and tracks, read the notes on stuck tracks and motors.

How to clear it

Power off first. Unplug a corded robot and lift it out of the pool. The page on what to do before touching it gives the order.

Then follow your own manual's steps. Every model opens differently. As one example, a cordless model's maker says to press a black latch on top of the robot to open the filter lid and remove the filter basket⁴. Yours may have a different latch, a bag, or a drawer.

In general, the clearing steps look like this:

• Empty the debris compartment and clean the filter³.
• Rinse only the way your own manual says. The garden-hose rinse that Maytronics gives is that one cordless model's instruction, not a rule for all robots⁴.
• Look at the intake opening for leaves, hair or pebbles.
• Put everything back, with the cover seated as shown in the user manual³.

A page from another maker sums up the clearing step: empty the debris compartment and clean the filter³.

Don't skip the reseat

A cover or lid that's sitting slightly off can leave a gap that changes the flow. The robot can then flash the same warning right after a clean-out. Make sure it clicks or locks as the manual describes.

When the light stays on

Run it for a minute in the pool with nobody swimming and watch from the edge. If the warning is gone, you're done.

If it returns straight away, the filter probably wasn't the cause. Look at the power and cable page next, or the one on stops partway through.

A full filter can affect more than the cycle. One maker lists a clogged filter as something that can affect the robot's climbing ability⁴. So if wall-climbing got worse before the light came on, the filter is a good first suspect.