Danner Mag Drive pump making noise...

[Mastiffman]

Just picked up one of the these used and all that it need was a little TLC and a new impeller. the old one looked like is was all scraped up from sand or rocks in the chamber. Chamber was to bad all all and only on one side. Still felt basically a little rougher than the smooth side.

So my dilema is that the Pump is being used externally and is making a noise like air is caight in the chamber. but the interesting thing is that when I pinch the output hose (1"ID) to restrict flow, the noise goes away?

Anynoe have any experince with these pumps? Will the noise go away after time. or shuld I pull it apart and put some marine safe Silicone lube on it? I have some that is resistent to salt water breakdown. But the unti is on a freshwater tank

by the way, I have it hooked up to a red Sea Ocean Clear Filter Canister without a cartridge in it... Was just trying to get an idea of it's output...

Thanks in advance.

 

[Mastiffman]

ANy takers on this issue?

 

[duanes]

If the inside chamber is worn badly, it can cause even a new impeller to wobble, and create cavitation (which has a crackling sound).
I had a Mag 500 that wore out because I used play sand years ago, the impeller wore out and, where the shaft sat, created a slight figure 8 in the pump housing, made the pump unusable.

 

[Mastiffman]

Thanks for the reply. There is only very mild scratches on one side of the inner impeller chamber. Thats all though.

Do have an idea why the noise would stop of I pinch either the intake or output hoses though? Would this indicate something else?

 

[duanes]

Many Mags have an O ring (more of an oval ring), or gasket. If it is worn, or missing, this might allow air to get in and cause cavitation.
If when pinched it stops making noise, you may be sealing a pin point air leak by pinching.
What kind of noise? Cavitation is air bubbles collapsing into the impeller, and sounds like crackling.
Tiny are bubbles can pit, and ruin impellers.

 

[Mastiffman]

Not a pin hole are anything becasue it doesn't matter where I squeeze...

If it were cavitation, would there be micro bubbles coming from the output nozzles? Because that's not happening.

 

[Mastiffman]

Just wanted to give an update on this thread. The noise was from air being sucked into the system and then getting caught in the Impeller chamber continuously. Tese things are as quiet if not more quiet than FX5's...