Impellar in powerhead.

[merman]

How often/ when do you know to replace the impellar ina powerhead? Why does a powerhead find it hard to turn over and start pumping water sometimes?

[Littlefish]

Odd no one has replied to this. I'm sure someone on the forum would replace impellers once in a while, unlike me.

When I find a powerhead playing up I pull it apart and scrub all the bits clean. Seems to do the trick. When it ceases to function altogether I send it off to the landfill and plead with my wife to buy me a new one.

Fred

[kalebjarrod]

the impeller in a powerhead normally stops working due to the fact that the electromagnet had warp slightly in the head unit

hence the reason i throw them and get new ones

when they find it hard to strat its useually due to a build up of algee in and around the impeller

(would have answered sooner but i missed the therad sorry)

[Littlefish]

Never ceases to amaze me how that brown algae can thrive under impossible conditions. Attaches itself to an impeller whizzing around at enormous speed and grows in absolute darkness. There's hope for life on Mars yet.

Fred

[Merrilyn]

Hahaha good thought Fred. You know, if we wanted to culture it, we probably couldn't.

[Fishpimpin73]

Could have sworn that I responded to this one in some length...........



Must be getting old

[oscar]

As Kalebjarrod said, its usually only necessitated by a mechanical failure. I have had two types:
Shaft Warp, causing off-axis rotation and wear of the magnet and/or the tight little recess in which it rotates.
Impeller Failure, the actual plastic component breaks off, i presume as a function of aging.

Either way these failure mechanisms usually provide an elevated/audible vibration or knocking noise, and are fairly abvious when the unit is dismantled.

[merman]

Thanks for the info guys, I remember working in an aquarium when I was younger and I was amazed at how many customers came in b/c they broke the shaft of the impellar they're fragile little bastards!

[oscar]

There is a reasonably simple engineering explanation as to why this happens. It's basically linked to design tolerances and quality control. If these items are not dynamically balanced well enought, then it increases the cyclic loading, which causes the plastic to work-harden and become brittle quite quickly due to the rotational speed and duty cycle of the components.

There you go. A simple xplanation for everything...? Warning: I have a tendency to be a little too analytical.

[Littlefish]

Cyclic loading. Dynamic balance. Love it when you talk like that! I woulda just said it's broke!

Merrilyn, you got that right about growing algae. It's like gardening, where I figure plants can be broadly divided into two groups - those that you can't get to grow and those that you can't stop from growing.

I have learned to love the plants that I can't stop from growing, so I am a happy gardener. My dear wife calls them weeds and says I'm lazy, but it's not true.