are you measuring head as only the vertical rise of the pipe from the pickup point where the pump gets its water from ?
If so, i am getting screwed because at 6feet mine is drawing like 450 watts, I have been trying to figure this out for about 3-4 weeks now. I am also throttling pump back at output. It is at about 70%.
Joe
Yikes! 450 watts! Do you have the standard Hammerhead or the Hammerhead Gold? Does it have a marathon motor or baldor? My wattage reading is 332 when I have it wide open (no throttling back) at 9' of head. See below for the factors I used to determine head pressure.
Are you guys factoring in the "head" due to plumbing and horizontal flow ? My dart is rated for 3200 gph at 5', but I only expect to get 2000gph from it because the effective head is 10' after accounting for elbows, valves, unions, horizontal run, etc. - basically all the friction/turbulence loss.
More head = more energy to drive it
Simon
More head sometimes results in an increase in wattage draw, but more often than not, you will actually see a drop in power consumption (see pump curve chart below). I notice a pretty substantial wattage drop when I throttle my pump back. Wide open it pulls 332 watts, but if I give my ball valve a 1/8 turn (effectively closing my ball valve 50%), the wattage draw drops down to 290. In fact, closing my ball valve by any amount results in a drop in the wattage reading on my kill-o-watt. See below for how I got to 9' head pressure.
Actually, the more head.... The less flow..... Less watts drawn. The pump is not working as much.
This is typically the case, but not always. Per the flow chart, the pump draws less wattage at 2' and 4' than at 9' or 13' of head, but wattage drops off when you get above 13'.
My main concern is that the "maximum wattage" listed for this pump is 297 watts, so regardless of the head pressure, I shouldn't get a reading over 297.
All of the flow charts I have been able to find (see below from Bulkreefsupply) seem to have photos of the older Marathon motor (mine is a Baldor). Perhaps the new Baldor motors draw more watts than Marathon's?
Pic of my pump (notice how it looks nothing like the one on bulkreefsupply's website):
Plumbing specs:
Inlet: 2" Flex PVC in (I have a barbed reducer fitting that goes from 2" barb to 1.5" MPT into the pump volute)
Outlet:
1.5" hose through 1.5" ball valve, expanded to 2" flex PVC after the ball valve. The vertical run is 8' that T's off (6' one direction and 2' to the other) to my returns which are simply bulkheads drilled into the top of each side of the tank. I have a 90 degree elbow fitting at each return into the 2" bulkhead fittings, so I figure the 8' of true vertical head, plus the T and 8' of horizontal runs and lastly the 2 90 degree fittings gives me roughly 9' of head (As you can probably tell from my plumbing pix below, I'm no pro here, so correct me if I am offin my head pressure calculation).
Alex
