Centrifugal pumps, flow restriction and noise

bobkoure · Post by **bobkoure** » Thu Mar 20, 2003 10:31 am

I have an Eheim 1046 centrifugal pump.
I had gone to the trouble of running 1/2"ID tubing and fittings everywhere because a posting on one forum had mentioned that restricted pumps were "noiser".
Using a vicegrips to slowly squeeze the tubing (using the screw in the handle) I found that there was essentially no change in noise - right up to the point where I had just about shut off all flow.
So, at least for this particular pump, restriction == pump noise is NOT true.
Just thought I'd save someone else the trouble as the larger hoses make things a bit more unweildy to deal with.
Bob
PS: I've an Athalon 2100+ (rated 1.73 Ghz) running at 2.1Ghz (200x10.5) that stays under 41C with a 1046 pump and ~950RPM 120mm fan (inaudible) exhausting case air through a 120mm "Black Ice" radiator. So, 20% boost, very quiet, not cold, but reasonably cool.
PS2: note that this is restriction on the pressure side. centrifugal pumps don't have much suction and restriction here might make noise - my system has a resevoir mounted right over the inlet so I'm unable to test suction restriction for noise.

Mirar · Post by **Mirar** » Sun Mar 30, 2003 10:06 am

I have the same experience. It's a very smooth noise. It sounds a bit unhappy when it draws air though (happened a bit when I was filling the system).

Restriction means lower water flow though, it might restrict the efficiency of the waterblocks (on the other hand it might improve the efficiency of the radiators).

My Eheim 1048 is slightly unbalanced though, so it vibrates. It's the loudest noise my computer makes...