Hum/vibration Hydrofoamer 9420 in iTech skimmer

[rrhardy]

I have a 1 year old iTech 200 Slimline (pump located inside the body of skimmer) that uses a Hydrofoamer 9420.04a pump. I recently cleaned it (soak in vinegar) and it now seems noisier than I remember - I can hear the skimmer across the room. Kind of a hum/vibration from the pump (not air or water noise). I took the pump apart and found that the impeller magnet had expanded and developed a split - so I ordered a replacement from Tunze (Thanks Roger for quick shipping!). But it's just as noisy with the new impeller. I replaced the bearings (rubber and ceramic parts) at the same time I changed out the impeller - old ones looked OK and were well seated (never removed) - I think i got the new ones in similarly. The sound is not clattering or clicking, just a steady hummmm. Bad motor body? Anyone with any ideas?
Thanks!
Richard

 

[rvitko]

Vibration is an issue with needlewheels because by nature they are unbalanced as they mix air and water and run in a state of cavitation as a result. The pump will never be completely silent, however, if it has grown noisier, the main culprits are a clogged bypass duct which purges air out of the rear bearing, or a worn drive unit, which you already replaced so we can largely rule out. Your pump should have a grey duct on one side of the impeller well, I would pull this out and clean it and the passage carefully, this duct blows water through the bearing to purge accumulated bubbles. I would also be sure the bearings are fully seated and have no tears in the silicon sleeves and no chips in the ceramic. It may also be that the volute has clogged so you get a higher ratio of air to water, I would be sure this is clean and the intake strainer is clean.