Trigon 350 Problems

[hitchins]

Hi, newbie here. Just purchased a second hand Juwel Trigon 350 but are having problems with the powerhead. As soon as you put it in the water it stops, but works out of the water. Any suggestions?

Thank you in advance.


Got it working now!

 

[Timmy_Bee]

i dont think it a good idea to have them on out of water. This can damage the motor

 

[waterdrop]

i dont think it a good idea to have them on out of water. This can damage the motor

Good comment Tim! Its my understanding that that's true, its always bad for pumps that are designed to be submerged to be on and trying to push against only air. I'm not sure what the failure mode is (wouldn't it be interesting to hear from an engineer, a pump designer!) I suspect it either may be that it spins so fast in air that it overheats, or that it just overheats because it is supposed to be using the liquid for better cooling, or it may be that the lack of mechanical resistance against the impeller blades causes some magnetic/mechanical change within the motor that causes damage.

Perhaps OM47 will happen on this, I think he may have had some pump experience even outside of the hobby? Or some other engineering type among our members.

I think it even gets more relavant for our beginners not just because of letting a pump run out of water but also because a pump of a particular design needs sometimes to be run within a particular height range.. for instance, setting an external cannister filter up at the level of the aquarium could damage the pumphead because it doesn't have the pressure resistance of more water above it and it will "cavitate" (under low pressure liquids trashed by blades will form "vapor pockets" that can damage the pump after a while.) (OM, correct me if I'm off..)

WD