Vertical pipe above check valve, is it filled with water always? (external pump)

[ShinDiors]

Was thinking putting an external sump pump outside the garage. Shortest pumping distance will be pump straight up and it will meet the gutter downspout which goes down thorough an elbow into a horizontal pipe around the back of the house, otherwise I will need 20 ft pipe on the driveway to street side. Two concerns:

1. Is the vertical pipe above the check valve always filled with water, even if when the rain stops? If it is, then freezing inside that section of pipe might be a concern.
2. Is there a way to connect this vertical pipe from pump to the downspout's discharging pipe so that the pressurized water would not block the gutter water which relies on gravity to drain down.

Thanks a lot.

 

[LLigetfa]

A check valve would normally hold water above it unless it is faulty. In some applications, the check valve is actually modified to slowly leak back which can work OK in cases where the pump might run frequently at times and not at other times.

On my sump pump, I chose not to use any check valve but rather a weir with air gap. The water that goes uphill to the weir continues downhill from there. The air gap prevents siphoning. The short uphill section drains back into the sump pit.

I used smaller diameter pipe on the uphill section since it is forced flow and larger diameter on the downhill section that is gravity flow.

 

[Sponsor]

 

[hj]

If you run the discharge pipe downhill from its high point, you can install a vacuum relief valve there and it will prevent siphoning the discharge back into the pit when the water in the riser drains back down to the pit, thus not requiring a check valve or "air gap".

 

[Reach4]

2. Is there a way to connect this vertical pipe from pump to the downspout's discharging pipe so that the pressurized water would not block the gutter water which relies on gravity to drain down.

You could put in a wye into the downspout, and discharge into that.

Maybe you could put something in in such a way that it would let you insert a leaf blower tip pointing down to clear the long pipe.
Easier would be to put a hole into the downspout, and insert an elbow pointing down. The question then is whether leaves would accumulate at that spot on their way down. I am not a pro.