Mag Pump construction

[murfman]

So I did a major cleaning of my tank and all of its accesories yesterday and I took apart my skimmer's pump, a Mag 9. I love the way they are screwed together and the impeller cover just pops off. I cleaned everything up real good and when I went to put everything back together I noticed a flapper valve where the impeller pushes water into the return hose. Anyone know why this is there? I have never seen anything like that before.

 

[reefkoi]

sounds like a check valve?

 

[murfman]

Thing is, it doesn't matter what side of the outlet it is on, water will still flow through.

 

[reefkoi]

I dunno, maybe someone in the "lighting filtration & other equipment" section of RC will know.

 

[calvin415]

Got any pics Paul? I've had tons of Mags in the past and never seen anything like you are describing before... Usually it's magnet/shaft, impeller, gasket and outer casing with 4 screws. ???

 

[murfman]

No pix, I already put it back together and re installed it. It has 6 screws and this is at the top, where the impeller pushes water into the return line.

 

[Huhhhhh]

<a href=showthread.php?s=&postid=10684475#post10684475 target=_blank>Originally posted</a> by murfman
No pix, I already put it back together and re installed it. It has 6 screws and this is at the top, where the impeller pushes water into the return line.

I have a Mag 12 and that flapper broke off and was spinning around with the impeller really messing up the flow. I threw it away when I cleaned mine. I couldn't figure out what it was for either. Pump works fine without it.

 

[murfman]

I was told it is to prevent cavitation, inside the chamber and around the blades.

 

[Huhhhhh]

<a href=showthread.php?s=&postid=10685587#post10685587 target=_blank>Originally posted</a> by murfman
I was told it is to prevent cavitation, inside the chamber and around the blades.

I was using my pump on a protein skimmer so I don't know if it was cavitating or not when I put it back together. When it broke off I literally had no flow coming out because it was jammed under one of the impeller blades causing it to drag.