I got the pump described in the web site below last year. I got the VSB
250 V or model 8094 which is the 1/3 hp version for $100 Canadian.
I am a hydraulics engineer and knew that I needed a high lift pump with more than double th typical sump pump flow capacity for my house. This pump has much more lift ability than typical sump pumps and much more flow rate. In your case the higher flow capacity would be the interesting factor as it seems that you may have a higher than normal inflow problem. If you use 1 1/4 piping you should get at least 20 gpm and more likely 30 gpm from the 1/3 hp pump. The only possible negative would be if the sump barrel is too small. A small sump has very little storage and the float switch only allows about 6 inches between on and off levels. A pump that has too much capacity for the storage available in a 6 inch rise would cycle too much - maybe only a few seconds between starts and stops. The
1/4 hp pump would provide a lot of capacity as well (also near 20 gpm) and would cycle a bit less and therefore last longer.
I can not vouch for the quality of this pump as I have had it for only one year but so far so good. A visual inspection shows that the design details are good but the materials are less robust than my old pump which cost over $350 and only lasted a year and a half and had very poor design details but looked robust. I can buy a lot of the cheaper pumps for what one expensive one cost me. I put two pumps in so I have a spare if one fails but so far the spare hasn't come on. I installed the spare higher than the main pump simply by hanging it on a rope and it has a separate pipe system so it would double the flow rate if the first pump couldn't keep up. There is an alarm set lower than the second pump which would have sounded and been noted by the monitoring company if it would have ever been started. Note the over-design at the engineer's house.
The installation described by RonB is excellent. I would add only a layer of felt landscaping cloth around the outside of the sump so that dirt is filtered out.
Also, get the largest diameter sump you can find for sale near you - min of 24 inch diameter. That minimizes cycling of the pump and allows you to use the larger 1/3 hp pump which may help with your high inflow rates. You could try the 1/2 hp pump but that may be overkill and if it cycles too much it will burn out and you will get flooded again. A good plan may be to start with one 1/4 hp pump and if there is ever a situation where it can't handle the flow then get another pump, maybe the 1/3 hp, and hang it in the same sump above the first pump. Use separate piping. Most of the plastic sumps have plenty of room for two pumps. Be careful that both float switches can move freely.
A 15 amp circuit has ample capacity for two pumps as long as you hang them so that they don't both start at the same time. Being the engineer I have separate circuits for the pumps but I was building my house new so I could put lots of circuits wherever I wanted them. Old houses may have to compromise on the number of circuits available.
One hp equals 746 watts so a 1/3 hp pump would be 249 watts, divided by
120 volts yields 2.1 amps. Pumps need double and sometimes more than triple the running amps to get started. That's why they burn out if they cycle too quickly - they need to run or cool off between starts. The brochure shows a max draw of 4 amps for the 1/3 hp pump which is a starting draw of double the running current, but I would use a triple draw to have a safety factor. Anyway, using a triple starting current draw of 6.3 amps for the second pump while the first pump was already running is only a total draw of 8.4 amps so a 15 amp circuit would support two pumps as long as they couldn't start at the same time. These are cheap Chinese made pumps so I'd estimate the higher current draws. In theory you could support two simultaneous starts as that would be only
12.6 amps but that is too close with no safety factor. I don't recall if the pumps are rated with or without power factors which would be fine either way for non-simultaneous starts but would cause the breaker to trip for simultaneous starts.
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