CatWhat Posted April 5, 2013 Report Share Posted April 5, 2013 I purchased this propeller several months ago and put it in my 55 gallon for some extra circulation. After only running for a couple of hours I heard this knocking coming from the basement and found that it was the propeller. After I did some investigating I found that even the way it is designed it would end up making this noise. I took some pics to help with my crappy description I'm about to give lol. The end of the propeller shaft is grooved/notched and so is the inside bearing column of the cage/guard. So these two notched pieces can mesh together causing the prop to start banging and even stop and stalling the motor.Just wondering if anyone has had this trouble with these type of propellers. I'm planning on filing down the notched edges on the white propeller shaft to prevent this from happening, but I shouldn't need to do anything really. Thanks for the help. Quote Link to comment Share on other sites More sharing options...
laurensdad Posted April 5, 2013 Report Share Posted April 5, 2013 Take it back to the store you got it from Quote Link to comment Share on other sites More sharing options...
ckmullin Posted April 5, 2013 Report Share Posted April 5, 2013 take it back. next time get a hydor. same price and better engineered. Quote Link to comment Share on other sites More sharing options...
Fisher Posted April 5, 2013 Report Share Posted April 5, 2013 (edited) I assume that you would have exchanged it if that was an option. I ran the 500 model in a cistern for a few months. It ran quiet and it pushed water until it was time to remove it. Here's some information for you to consider. By the way the propeller blades are inclined, they are intended to spin counter clockwise to push water away from the motor assembly. The force of the blades pushing water away, also draws the propeller back into the motor assembly (and away from the guard), and in turn, presses the motor assembly back into the suction cup. The same physics that propels a boat. Those notches - the lands on the guard and the lands on the end of the column aren't intended to mesh during normal operation. The flat section on your propeller column and on the gaurd will lock the propeller if the pump started running in reverse. It's a safety design CatWhat Are there burrs in these locations? It'd be helpful to know if your pump is, in fact, pushing or pulling water. If it's pulling water, then the pump is running in reverse; the knock is the motor overcoming the safety lock. I would expect a burr to form on leading edge of the flat where the propeller shaft climbs the groove in the gaurd. If it's pushing water, then it seems to me the prop is too close to the guard. That could be for a variety of reasons: 1. the propeller column has crept up the steel shaft, 2. the shaft isn't seated far enough into the motor (and too far into the cage), 3. the cage is pushed too far back on the main motor body... Edited April 6, 2013 by Fisher Quote Link to comment Share on other sites More sharing options...
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