Its about a year old.

There was some roots starting to get in the grates, but theres nothing actually caught in the impellors nope. But i can't open the motor unit as its sealed plastic.

But as you say, it works fine, then just cuts out, so its definatly some kinda of protection kicking in and shutting the power down on it.

Won't restart straight away, but give it a bit, and try again and it fires up absolutly fine (again, for another 5 min or so).

[Edited on 21-06-2007 by VXR]

Sounds to me like its the thermal overload protection cutting it out. You sure nothing is caught in the impellors? How long have you had the pump for? Maybe its just time for a replacement if you've had it a good few years? When i clean my filters the pump stays on but slide valves cut off all the flow, and the pump has never cut out, so it sounds like there is definately something wrong with it, not just because its struggling with the smaller gaps on the fitler cage.

Anyone got any ideas.

Got a fairly decent pump which is in the lower pond. This runs into a filter, then out into the top pond, then runs down a stream back to the bottom pond.

Thing is, the pumps going on a mad one the last few days. It works absolutly fine, then after about 5 minutes, just stops.

Leave it for 20 min, and it works fine again for another 5 min.

I took the pump out last night, gave it a bit of a clean up, removed any pond rubbish and tried it again. Same issue.

I've got the vents on the minimum gap, and its been fine all year. Im going to try opening the vent a little more tonight (as pond greenery sticks on and may have reduced the gaps?) and see if that works. The only thing I can thing of is that not enough water is getting to the pump (even though its submerged) and its getting hot and shutting down.

Anyone got any ideas? Water flow seems to be fine when it is running.

Cheers