Silencing Hydor L30

[Aris]

i usually prefer to use eheim pumps. but i needed somthing smaller for this specific project.

my systems basically dead silent right now. but if i turn off everything that makes noise in the room i can still hear the pump making a little noise. the 3, 120mm fans in the case are inaudible even within 1ft.

so i wanted to get opinions.

what do you think would be the best way to silence this pump?

space is an issue, i prolly have about 1/2-1" of space on all sides.
money is no object though, so dont hold anything you think might work just cause you think it'd cost too much. id love to hear all your ideas

 

[101]

The first thing you need to do is mount the pump so that the axis of rotation is normal to the mounting surface. This allows some of the pump vibration to be self canceling. Second I would construct a mount from very low durometer sorbothane (from mcmaster-carr), and isolate the screws properly. This means no screw through a portion of the case, then through the pump. You want to "float" the pump on axis on the sorbothane. You want it nice and loose.

Once you do that properly your main vibration path becomes through the tubing itself. Larger service loops of softer tubing works well. Also don't forget the tough outter rubber jacket on the AC line of the pump, this can cause problems as well. I recommend carefully stripping the outter jacket to the line, neutral, and gnd connections and braid them to your AC connection again with a nice service loop. This not only eliminates transmission through the black insulation, but the braided harness is more flexible due to all the bends of the individual wires.

Taking all those steps into acct will give you an absolute vibration free pump installation if done properly with a little common sense. Experiment and test small subsets of your build so as to isolate individual problems, doing it all at once and then band-aiding your shit afterwards will leave you frustrated without results.

EDIT: Remember the best way to test is to "feel" for vibration, don't listen for it.

 

[Aris]

i dont have any vibration. thats not the problem. its already isolated from the case.


the sound isnt from vibration at all. its like a soft clicking noise, i dont think its air, but it sorta sounds like that. but i blead the system very well before i closed it up.


im thinking of getting some of that thick dynomat type stuff and cutting out the shape of the pump into 2 pieces and sandwitching the pump in between them.

 

[101]

Mass loading the pump will only improve it's vibration performance, if that's not an issue I wouldn't worry about it. If you're sure you got the air out and there's no cavitation, it could be the impeller loose on the rotor. Super gluing the impeller used to be a common remedy, just remove it when you glue them so you don't stick it to the shaft.

 

[diredesire]

personally i think the barbs are a little prone to leakage if you make the pump push hard enough...

Teflon tape (use a LOT) the barbs and put a little bit of vaseline on the o-rings (in the small 1/2" barbs). This'll prevent any air leakage out the barbs (i get a little bit of sucking noises too, i think air is getting into my loop).

The big kicker for this pump i think is the front mount where the impeller is inserted. I think if you jostle it the right way, air starts getting in. The best remedy is to take out the o-ring, and put some silicone sealant into the groove in which it resides. Replace the o-ring and perhaps put some more sili-seal on top of it, replace the impeller housing and make sure you seal it shut tightly.

I've also had problems when my pump isn't mounted 'normal to the mounting surface' (i've never heard that usage of 'normal' before, but i like it )
It gives a bit of a rattle.

Anyways, my 2 cents.

 

[2Fresh]

If it is vibrating just stick something under it. My Hydor L30 (320gph) is super quiet. About the best pump I have owned.

 

[Yourself]

Originally posted by 2Fresh
If it is vibrating just stick something under it. My Hydor L30 (320gph) is super quiet. About the best pump I have owned.

he said it's not vibrating.

I had the same issue and I could not get the clicking to stop. I tried different impeller mods and couldn't get it to stop. There are some good suggestions in the post a couple up from this one that I'm actually gonna try.


Self

 

[2Fresh]

Oh, I just read the 1st post.

 

[Aris]

Originally posted by 101
If you're sure you got the air out and there's no cavitation, it could be the impeller loose on the rotor. Super gluing the impeller used to be a common remedy, just remove it when you glue them so you don't stick it to the shaft.

this is exactly what it sounds like. like the rotor is loose and just goes click click click against somthing while its running.

can you please explain this super glue thing. i dont quit understand what exactly you mean. also id prefer to do somthing that doesnt require draining the system as its a completely closed loop with no fill tube. the water wetter mix took over 2 weeks to get the smell off my hands after sealing up the system.

 

[kleptophobiac]

TBH, having no fill line is a PITA. I did that for a while, and I couldn't stand it.

The idea is the super glue the impellor to the magnet on the shat, so there is no opportunity for the two to click against each other. Do not glue anything to the shaft. The shaft is motionless, and is simply an axis upon which the impellor and magnet rotate. There should be some plastic fins that loosely lock the magnet and impeller together. It is loose to prevent clogging in pond environments, but is just a noise maker in a computer environment where pond scum is no longer a problem.