I recently bought a house which is equipped with a grinder pump in the basement. It seems that when the grinder pump kicks off there is a loud bang that comes from inside the housing of the pump. I was told that it was a door inside the housing slamming shut. Is this normal? It is a violent slam and it seems to me that in time it may cause damage. I would appreciate any help. Thanks.

I was told that it was a door inside the housing slamming shut. Is this normal? That "door" is called a check valve and if it didn't slam shut you would have all the sewage in the discharge hose draining back into the pit as soon as the pump stops. F itbothers you you could try replacing the check valve but I can't guarantee that it will be less noise. Good luck. Tom