By continuing to use this site, you agree to our use of cookies. Find out more
Forum sponsored by:
Forum sponsored by Allendale Dec 6th

Water pump shaft clearance?

All Topics | Latest Posts

Search for:  in Thread Title in  
Vic14/08/2019 15:09:47
2323 forum posts
12 photos

I bought an Aquarium filter a while back and I had to send the head back because it was very noisy. It was returned with a new impeller but it’s still noisy so I’m now in contact with the importer. There is only one moving part on these pumps, it’s an impeller with a tubular magnet with plastic vanes. This rotates on a ceramic shaft. In operation there is a humming noise and vibration coming from the head. I have a similar unit from another vendor and it’s virtually silent. I’ve measured the ceramic shaft with a mic and it’s 2.48mm. Sorting through my drill bits I found the end of a 2.56mm bit just fits in the impeller opening. It doesn’t sound much but the gap between the impeller and shaft is quite noticeable in the hand. What would you expect a reasonable clearance to be for something like this. Anyone have any ideas? It may be that something else is causing the noise but I can’t think what that may be.

I’m not prepared to do it at the moment but next time I clean my other filter I will check the clearance on that just out of curiosity.

Grizzly bear14/08/2019 19:00:20
203 forum posts
6 photos

Hi Vic,

Picture or link please.

Bear..

Vic14/08/2019 19:13:05
2323 forum posts
12 photos

Its part number 7632600

https://www.eheim.com/resources/product//219/downloads/10/EHEIM_classic_250_Ersatzteilliste.pdf

 

Edited By Vic on 14/08/2019 19:18:31

Brian Sweeting14/08/2019 23:52:26
385 forum posts
1 photos

Might be a silly question but is the pump motor section full of water otherwise a dry running pump will be noisy.

Neil Wyatt15/08/2019 09:20:04
avatar
Moderator
16738 forum posts
689 photos
76 articles

In my experience these are usually a pretty free fit, although I have never measured one.

They usually hum if jammed or airlocked.

Neil

Neil Wyatt15/08/2019 09:20:34
avatar
Moderator
16738 forum posts
689 photos
76 articles

In my experience these are usually a pretty free fit, although I have never measured one.

They usually hum if jammed or airlocked.

Neil

Vic15/08/2019 14:21:32
2323 forum posts
12 photos
Posted by Brian Sweeting on 14/08/2019 23:52:26:

Might be a silly question but is the pump motor section full of water otherwise a dry running pump will be noisy.

Yes it’s full of water. Excess noise is often blamed on trapped air but there’s a distinct difference from the noise trapped air makes and this humming/buzzing noise. You can also feel the vibration through the housing.

The frustrating thing is that these pumps used to be virtually silent in operation when they were made in Germany. Not sure where they’re made now but they no longer have “Made in Germany” on them any longer.

looking on the net I’m not the only one to have this problem, lots of others have suffered it with this particular model and others in the series.

JasonB15/08/2019 15:01:49
avatar
Moderator
16521 forum posts
1755 photos
1 articles

I ran a couple of those filters for years and always quiet, airpump probbaly drowne dit out but expect they were the older ones.

As Neil says they are quite slack, I have another larger pump where the impeller is held in rubber "bearings" and my Messener Koi pond pumps have plenty of freeplay

Vic15/08/2019 15:02:09
2323 forum posts
12 photos

The impeller is made of some kind of magnetic material. I’m wondering if I can mount it in a collet and drill and sleeve it to get a better fit?

All Topics | Latest Posts

Please login to post a reply.

Magazine Locator

Want the latest issue of Model Engineer or Model Engineers' Workshop? Use our magazine locator links to find your nearest stockist!

Find Model Engineer & Model Engineers' Workshop

Latest Forum Posts
Support Our Partners
cowbells
Ausee.com.au
Eccentric July 5 2018
TRANSWAVE Converters
Warco
Eccentric Engineering
ChesterUK
Meridienne Dec 4th 2019
emcomachinetools
Allendale Electronics
Subscription Offer

Latest "For Sale" Ads
Latest "Wanted" Ads
Get In Touch!

Do you want to contact the Model Engineer and Model Engineers' Workshop team?

You can contact us by phone, mail or email about the magazines including becoming a contributor, submitting reader's letters or making queries about articles. You can also get in touch about this website, advertising or other general issues.

Click THIS LINK for full contact details.

For subscription issues please see THIS LINK.

Digital Back Issues

Social Media online

'Like' us on Facebook
Follow us on Facebook

Follow us on Twitter
 Twitter Logo

Pin us on Pinterest