Tuning the snapper for BEP - some experimentation
by, 10-22-2012 at 10:44 PM (1115 Views)
Well, I finally finished installing the snapper pump. I learned a few things along the way and I'll try to give you as unbiased account as I can here.
First thing - I'm going to take a quick tangent here and report some about my personal experience with reeflo quality. I opened up my brand new reeflo pump and found the dart impeller cracked right through the middle upon arrival. It was as if someone had tightened it too much or it was subjected to an extreme temperature difference and the shaft expanded faster than the impeller and split it. Since I didn't want to run with the dart impeller anyway, I turned my attention to the snapper impeller and found that it had been drilled at an angle so that it wobbles a bit when you spin it on the shaft by hand. I can only imagine that this will wear the seal quickly and lead to a reduced lifespan for the pump and possibly some efficiency loss. I wasn't too impressed. I quickly took some pictures and sent them off to customer support at reeflo. Though I did get a quick response after my initial email stating that some replacement impellers would go in the mail immediately via USPS priority mail, they have not shown up more than a week later and I'm no longer getting response from reeflo via email. Ugh.
I put the wobbly snapper on the pump and plumbed it into the system to replace the Gen X 55hp pump I have been using for the past few years. I chose the gen x pump because I used to have my sump in the basement and pump the water back to the main floor. Since, I have finished my basement and moved the aquarium downstairs, so I don't need a high head pump. I used all of my old manifold and added a couple new 1" drops for expansion and my hurricone skimmer. Before disconnecting the old pump (by the way, supposed to be a 1150 gph, 28ft max head, 170W pump), I hooked up the kill-a-watt to find that it was still drawing a healthy 300W! That's a lot of juice! I removed the Gen X and moved it to the side and installed the snapper (2600 gph, max 11' head, rated at avg 94 watts or peak 105 watts). The kill-a-watt measured the snapper running at 153 watts without any tuning. I installed a valve on the business end of the pump and was eager to throttle it back to see the magic. To my disappointment, the wattage dropped from 153 watts to 147 watts with a fairly aggressive throttling. While I was happy to see myself save 150W (about $10 / month where I live), I was expecting a bit more.
So, why do you think I'm getting such a different number than advertised? Why does throttling make such little impact? I've basically got a 1.5" all the way to the delivery points if you consider that I have pipes in parallel. The highest drop is probably 7', but the average drop is probably 4' or less measured from the water line in my sump to where the water dumps out. Like I said, I suspect the wobble in the impeller accounts for some of the efficiency loss, but I can't imagine that it's the largest factor. My gut says that the specs on these pumps aren't regulated by anything but the reflection of the value of the brand and that maybe everyone fudges the numbers to look better than they really are... I'd be interested to hear YOUR take