I have 2 sump pits for my house. 1 is in the basement and the 2nd is outside. the one in the basement is fine. but the pump out side is toast. I am going to replace it with a zoeller 57m.
now the pit is about 10ft down to the bottom. I am worried that if I put a check valve on that the pipe will freeze up in the winter.
other thing is I am not sure if the out side pit is meant to be a over flow, back up, or what? It is only about 8ft away from the one inside. It looks like it may be a bit deeper to the bottom then the one inside.
If the pit is deep enough or wide enough to hold a large amount of water before the pump has to start then you do not need a check valve.This lets the water drain back down to prevent freezing.
For a long time I have suggested having 3 cubic feet (a little over 20 gallons) of space below the turn on level and not filled with rocks.
With the entirety of the pump below about 4 feet and the lid at least semi-sealed to prevent air infiltration and exchange, the pump and pit should not freeze up.
The good conscientious technician or serviceperson will carry extra oils and lubricants in case the new pump did not come with oil or the oil was accidentally spilled, so the service call can be completed without an extra visit.