• You are viewing the forum as a Guest, please login (you can use your Facebook, Twitter, Google or Microsoft account to login) or register using this link: Log in or Sign Up
  • You can now follow UKAPS on Instagram.

Return Pump Squeking

NotoriousENG

Member
Joined
17 Jul 2021
Messages
107
Location
Eastern USA
Hi All,

My return pump (Jebao DCP 2500) started intermitedly squeaking today. Thinking something was stuck inside I opened it up and found a ton of mulm and bio film which I cleaned out. Now that it's back in the sump it is still squeaking. Less severe then before but constant instead of intermittent. I'm thinking maybe it needs to be lubed somehow?


Any suggestions on what the cause is and how to fix it?
4d912559b4975cfe86261dbcc583ebb7.jpg
eefbd927c0647ec00bdb3c430c18a979.jpg
c019a5208a1b0f52d95f94f74a6cd8dd.jpg


Sent from my SM-G970U1 using Tapatalk
 

zozo

Member
Joined
16 Apr 2015
Messages
8,167
Location
Netherlands
These submersible pumps are self-lubricating with a capillary water film between the magnet and the housing. This water film prevents the magnetic shaft and impeller from oscillating and touching and rubbing the housing. This rubbing is the squeaking noise.

Thus if it runs dry into an air bubble it starts vibrating and will make that noise, these pumps are not self-priming then move them around a bit underwater to get all air out.

If it still makes that horrible noise then indeed as @foxfish says inspect the ceramic shaft for excessive play. And depending on the pumps construction quality also check the sockets holding the ceramic shaft in place. Some higher quality pumps have little rubbers caps as sockets to dampen vibration. I've seen them come out with taking apart for cleaning, if you don't notice losing them and then after putting back together the ceramic shaft will have too much play and be unable to centre properly and wobble like mad.

Anyway, the ceramic shaft should fit snuggly into the sockets of both parts without falling out. If it does you are either missing something or it has too much wear and play and it vibrates. I suspect you are likely missing a rubber socket cap or installed it incorrectly... :)

Here you see an Eheim ceramic shaft with rubber socket caps.
52006_1.jpg


or
images
 
Last edited:

NotoriousENG

Member
Thread starter
Joined
17 Jul 2021
Messages
107
Location
Eastern USA
Thanks for the replies everyone.

Good news, the squeaking has stopped and the pump is much quieter then it has been recently. I think @zozo was right and there was air trapped between the magnet and housing which took a while to work its way free.

The pump is new as of August so I would hope its not already being affected by mechanical wear. If so, I do have a spare pump I can scavenge parts from. I would just replace the pump with the spare, but the spare surges badly.

I'm also wondering if that level of biofilm build up is normal for only four months of use?

Sent from my SM-G970U1 using Tapatalk
 

zozo

Member
Joined
16 Apr 2015
Messages
8,167
Location
Netherlands
I'm also wondering if that level of biofilm build up is normal for only four months of use?

That brown gunk in the pump is from free-floating substances such as Tannins/Humic substances. They are so small similar to instant coffee or tea. Actually, they are both the same, instant coffee is a powder form and made to evaporate fresh broiled coffee under high pressure into steam. Then small particle powder precipitates to the walls of this hot chamber. This is dried and scratched off and collected and sold as instant coffee.

You might wonder why nobody yet tried, I'm pretty sure we could make instant humic substances like this as powder form in a pot. There might be a market for it.

Anyway if you have some degree of humic substances in your tank water this is so tiny it passes through the finest filter media and precipitates into the biofilm. The more tannins you have in the water the browner the gunk will be... :) The biofilm is pretty normal and builds up in a week, the colour depends on the above.
 
Top