I just got a new sump pump installed and the piping it drain it is about 1 1/4 pvc out of my house. goes into my old drain which is 2" underground out to the street. I plan to replace all of this when it gets wormer out. I need abot a 30' runn and it does slope down. My problem is the contractor did not glue the elbow on just pressure fit it and it pops off when it is cold. Could this be because of frezeing in the line? If so how do I fix that so I have a perment drain, also do I need a pressure relif incase something clogs it so it does not back up into my basement. How do I add this.