MCE600 lack of air and noisy pump

Answer:

Hi Steve

The dampening kit usually silences the pump if its in servicable condition and was the most cost effective solution I could offer. As the unit is second hand I'm afraid there isn't a lot we can offer as the vibration could simply be due to wear and tear. If the unit is under a year old and you have the receipt the retailer maybe able to help.

The vibration may be down to wear on the shaft or worse case internal wear to the impeller, this may be due to the age of the pump or lack of maintenance by the previous owner.

We do offer an updated pump that includes ceramic bearings and one piece impeller should you wish to replace the pump at a price of £122 plus P&P or you could try a new impeller shaft but as I say the wear might not be limited to the shaft.

Regards Tony

Response:

Hi Tony,

              I must admit, i'm reluctant to do that, as I paid £100 for it second hand, so with £122 for the pump I could have purchased a new one. Can you absolutely guarantee the new pump would be silent?? are there any structural defects with the skimmer itself that may affect its harmonics, that installing a new pump just won't cure? If I did purchase the pump, and it was no better, then could I return it if it has only been trialled?

 Regards,

  Steve.

Response:D-D

Hi Steve

The updated pumps are very quiet, equally its worth ruling out any vibration between the body and the aquarium and trying to pin point where the vibration is coming from first.

Have you tried running the skimmer off the tank on a flat surface into a bucket or similar? Drumming and buzzing can occur depending on the aquarium design or a cabinet as they can amplify noises.

Did you read this excerpt from the link I originally send?

The skimmer is constructed so that the pump is held solid in two places, 1 - by the inlet pipe at one end and 2 - by the sliding plate that jams behind the pump at the other end.

If you have a vibration noise then the first thing to check is that these are solid. The easiest way is to push down on the removable sliding plate, (the one that runs up the side of the waste cup towards the centre of the skimmer). If the noise goes away then this is the likely cause.

Much of the noise heard is not caused by direct vibration but resonant vibration. Resonance is when another item in the proximity of the vibration source which does not have to be in direct contact is caused to vibrate at a certain frequency due to the specific wavelength of the sound wave.

Using the screw on the sliding plate tighten it against the skimmer cup whilst pushing down the plate and this in most cases will sort the problem.

Models manufactured after 2006 are fitted with strip silicone feet which cushion the pump and reduce vibration noise.

Also check for side to side play with the impeller on the shaft. If you can feel play there it maybe the shaft or impeller is worn, this will cause the impeller to spin off center and vibrate, sometimes quite badly. This will require a new shaft or/and impeller. Also swap the red bushes over with the new ones if you havent already.

As i say though try and run the skimmer away from the tank in a quiet room and locate the cause of the buzz/resonance before ordering anymore parts as you may be able to locate the parts that need attention for a cost effective fix.

Regards Tony

Response :

Hi Tony,

              Thanks for your suggestions, I have tried the skimmer off the tank and into a 25 litre container with the lid cut off. The skimmer was placed on some books (yellow pages etc) and into the container. This made no difference whatsoever to the noise level, and the whole skimmer casing can be felt to be vibrating. I also noticed that adjusting the air intake made no difference to the bubbles produced. When doing this on my MCE300, the changes are instant. The plate that sits between the intake and return (that slides out) is very noisy, as is the whole casing itself. Is this common do you think?? it does seem rather bad?? I don't really want to pay for a new pump, and have it make the same level of noise as I already have. I believe they should just hum, rather than vibrate as I have read on the forums, and reviews etc. I have also placed foam between all areas of the skimmer that come into contact with the tank, again to no avail!! I have no hair left to pull out to be honest...

 Regards,

 Steve.

Response D-D

Hi Steve

Your results fall inline with a restriction in the air feed to the pump. Basically when the pumps air is restricted the impeller moves forward within the pump and rubs on the front suction plate.This causes the pump to vibrate as the needle wheel isn't designed to run with little or no air. The fact that you can open the tap and observe no change in the air volume from the pump plus the fact the air tap is noisy also backs this up.

Air bubbles being forced from the skimmer by high water flow from the pump also indicates a lack of air being produced by the pump as when the amount of air to the skimmer is reduced the ratio of water to air increases thus chasing out bubbles within the skimmer.

There are a couple of instances that would cause this to happen. I have listed them in priority with regards to your particular problem.

1. The most common would be a restriction within the venturi, stubborn calcium deposits can build up within the venturi that cannot be removed by normal cleaning. It requires a long soak in an acid solution such as vinegar or EzeClean  or cleaning manually with a drill bit.I have included a picture of where to clean.

2. The air tap is totally blocked with dust, the easy way to test for this is to remove the air tap completely, if air production increases and noise decreases you have identified the problem and a new tap will be needed if cleaning doesn't resolve this.

3. A block in the soft air line, this is uncommon but worth checking by blowing down the pipe or running a thin blunt rod down it

4 The flap inside the pump stuck to one side. The MCE600 pumps are AC pumps and as such may start up and run in any direction. The flap inside the pump redirects the flow according to the direction the impeller starts.If the flap is stuck and the impeller starts in a direction that runs against the flap the pump will run at reduced duty. This may cause the pump to run noisily and with reduced output/air.

I have included a picture of the pump flap, a soak in Vinegar/EzeClean should free the flap back up.

5. A restriction/block on the inlet pipe work/strainer, this would also present itself with a reduced flow from the pump so I don't think its applicable in your case.

6. A foreign object within the pump body or faulty impeller/shaft assembly. This would reduce the over all air/water output of the pump and cause the pump to become noisy.The impeller magnet surface should be smooth with no high spots/cracks and the impeller well should be free from foreign objects and smooth. There should be next to no side to side play between the shaft and the impeller, excessive play indicates wear and the shaft and or impeller will need to be replaced. If the impeller shaft is worn the impeller will run off centre, this will cause the pump to run noisily, at reduced duty and if the wear is particularly bad cause the pumps internal protection to trip as the pump starts to over heat.

 The grommets should be tight within their housing, if they are loose they may have shrunk and will need replacing.

 Any calcium deposits within the pump will need soaking for at least 24 hours with a Vinegar or EzeClean solution to break these deposits down.

Hope this helps Tony