FX6 pulsating knocking sound inside it

[Waterlife]

FX6 pulsating after cleaning and maintenance.  There’s a knocking sound inside it too, maybe the pulsating is bumping things around in there.  It’s not an air issue, it’s sealed and valves are open.  There’s very little water coming out sporadically in small pulses to nothing at all.  It’s been fine for 18 months.  
many ideas?  

[AndEEss]

Did you properly prime it before starting it back up?

[Waterlife]

Yes I filled it to the top.  

[AndEEss]

On 3/1/2023 at 12:46 PM, Waterlife said:

Yes I filled it to the top.  

Is there water in the inlet and outlet hose?

[Waterlife]

Yes both lines are filled.  There is a knocking sound coming from the motor with every pulse, no water flowing out.  But the lines are pulsing like it’s trying to pump water.  

[mynameisnobody]

@Waterlife I’d check the impeller. It may need a good cleaning. 

[ColBud]

Second on checking the impeller. Not sure on fx6 I don’t use that but make sure any cover over it is in place and the impeller is seated properly.

[nabokovfan87]

The noise you're hearing is air being hit by the impeller.  Even if you purge it perfectly there's a few things going on....

A.  You might need to clean the pump / impeller so that the flow i strong enough that it can push out the bubbles.
B.  You might need to rock or angle the canister itself to push the air out of crevices and then let the pump push it out.
C.  A pinhole in the tubes that is pushing air into the canister.

[Rewcolee1]

I’d check the impeller as well. I typically have to replace mine every 18-24 months. It’s cheap and easy and certainly knocks the db’s down.

Edited March 4, 2023 by Rewcolee1

[Luciferkrist]

I support checking the impeller. When I set mine up last year it was doing the same thing and it ended up being a snapped impeller shaft. Dropped a new one in and works like a charm.