sump-pump
How often do I need to flush the sump pit with water? That is, pour water into it from a hose to change the water.
Also, can I do it in freezing temperatures? Inside the garage the temperature is about 10C but outside it's freezing.
The sump pump is not inside my garage but that of my neighbour.
It should definately come on before the water gets to that level. Is the float the kind that has its cord clamped to a pipe and it swings up and down? If its that kind, make sure that its not hung up on anything. You may need to manually run the pump to empty the water and troubleshoot the float. Lift it and see if the pump comes on. Does the float have a separate cord that plugs into the outlet and then the pump plugs into the back of the floats plug?
I agree that it should pump more than a half inch per minute. I would think it would be normal to empty the tank in around 20-30 seconds.
The main thing you will need to pay attention to is the head rating of the sump pump. I can't imagine a standard big box store sump pump would have any trouble raising the water 8 feet...every sump I've ever owned had to go at least that high. The horizontal run has a negligible effect on the capability of the pump (it's not zero, but it is very small compared to the vertical portion.)
Yo uwill need to make sure that the pump can discarge enough water at the head height to keep up with the flow of water into the pit. This is most often a guessing game, unless you know the volume of the pit and can time how long it takes to fill up under the worst conditions (perhaps a severe rain storm).
A pump curve tells you the flow performance (measured in gallons per minute or liters per minute) of a pump relative to the head pressure. To read a pump curve, you must first examine the units of measurement used along each of the displayed axes. The pictured pump curve displays head pressure in Feet (along the left-side y-axis) and in Meters (along the right-side y-axis). Increased head pressure is indicated as you travel up the y-axis. The flow performance is indicated in gallons per minute (along the lower x-axis) and liters per minute (along the upper x-axis). This is an indication of the output flow of a pump.
The pump curve is read by first determining the head pressure of the application in which the pump will be used. Once you’ve determined your head pressure, simply follow the head value you have selected from the y-axis horizontally to where it intersects with the pump curve line. From that point, move vertically to the flow measurement on the x-axis.
Best Answer
Approximately never.
If you notice things growing in there or bugs breeding, a bit of soap (liquid dish detergent would be my first choice) will usually do in the bugs by altering the surface tension, and chlorine bleach will kill off bacterial slimes if there's not too much water flow (so it stays put for a while.) If there is water flow it should never get too nasty.
If you are not experiencing problems/smells, leave it alone - or perhaps put a cover over it if it lacks one, which will keep things from going into it and causing problems (small animals drowning, for instance - or the bugs that might want to breed in there.) If it also serves as a floor drain, put a screened section in the cover to allow water to flow in.