Paul W wrote:

The backup pump currently will run, but not pump any water out of the
drainage hole. The pump's instruction says that if this occurs to
drill a small hole in the drainage pipe about 3 inches above the hole.

Can someone explain to me why this should work, before I start drilling
holes in my pipes?

Thanks,

Paul W

http://www.askthebuilder.com/195_Sum...uardians.shtml

Excerpt:

"The vibrations and inability to pump on occasions can almost always be
attributed to pump air- lock. When a sump pumps turns off, the water in
the discharge line between the pump and the check valve drains back into
the sump. If the pipe between the pump and the check valve is solid, the
air in the line will compress the next time the pump tries to empty the
sump basin. This compressed air can prevent water from leaving the pump.
A 3/16 inch vent hole in the side of the discharge pipe inside the sump
solves this problem. Check to see if your discharge line inside the pit
has this hole. If it does, make sure it is not clogged."