Conergy 1304-12 pump

gpigeon

I have now got one of the systems (discussed in an earlier thread) up and running but it is not performing quite up to specification.
I ended up with a 1304-12 pump coupled to a Sharp 123W (12V) panel via a Conergy LCB8 controller.
The design TDH was 137 ft but the pump will only pump to 130 ft with an open discharge pipe. The pump is still rotating at this head despite NO water actually being pumped. If I close the gate valve at the pump discharge the pump stalls (stops rotating) at 65 psi (147 ft).
The panel supplier has agreed (they had sized the whole setup) to replace the 123W unit with 2 x 80W units so that should fix the lack of head problem but may create another problem because the Conergy LCB is only rated for 8A (10A fuse). Any comments on this?
What puzzles me also is if the 1304 pump is a positive displacement pump......how can it continue to rotate without actually moving any water?
I must say that despite the above problem (not the fault of the pump) the Conergy slowpump is a very well built robust unit. I am impressed! It will be interesting to see how it performs in the long term.
Looking forward to your feedback.
Regards.
Bill W.

niel

Re: Conergy 1304-12 pump

do not worry about the 8amp limit as any motor, be it a fan or pump, will have a current rating and they usually don't exceed it. it is an indicator of what it should maximally draw naturally and not something you need to regulate so it is only saying what it will draw and is a self imposing limit just like a 60w light bulb having a current rating and not need regulated. as to a regulation need, the volts would possibly be a different story, but your controller handles that for you.
as to the pump running and no movement you hit the point of no return as the work the pump is able to do with the power available is only able to hit that certain height. this should change once the 2 80w pvs are in place as more power will become available to the pump. the height should continue in its increase until it reaches the max capability of the pump itself. though i believe you will see water movement with the 2 80w pvs, i don't think it will be moving very many gph as most of the power is dissipated in pushing the water up to that height.