MrCADMan
Computer
- Apr 6, 2002
- 1
I don't understand the dynamics of what's happening in what I describe below:
Our plumber, who has done good work for us in the past, recently installed a new Shellback
sump pump in our basement. Occasionally (not-repeatable in a technical sense- it occurs
randomly about five percent of the time), the brass check valve he used slams shut with a very
loud bang, and sometimes bounces, usually no more than two bounces. I can't believe that this is
normal, although he says that brass check valves are about all the same. I request info, both by
way of just general knowledge about the subject, as well as parts which either I or our plumber
can use in this line which won't exhibit this not-repeatable behavior.
I asked the customer service guy at Shellback if it is possible that somehow the pump is generating backlash, and he said no. Still, I believe that there must be some kind of active force on the thing over and above that of gravity and the seven foot water column. For a ball to accelerate that fast over a distance of two inches, some other force must be applied. I just don't understand the dynamics of the thing.
The valve is a LEGEND 1 200 W00 for 1 1/4" pipe. It was made in Taiwan. It is brass, threaded,
possibly model T-149, and it is eventually coupled to a PVC pipe. The 1/4" pvc outlet drops
about 7 feet.
Marvin E Walden
Troy, MI, USA
Our plumber, who has done good work for us in the past, recently installed a new Shellback
sump pump in our basement. Occasionally (not-repeatable in a technical sense- it occurs
randomly about five percent of the time), the brass check valve he used slams shut with a very
loud bang, and sometimes bounces, usually no more than two bounces. I can't believe that this is
normal, although he says that brass check valves are about all the same. I request info, both by
way of just general knowledge about the subject, as well as parts which either I or our plumber
can use in this line which won't exhibit this not-repeatable behavior.
I asked the customer service guy at Shellback if it is possible that somehow the pump is generating backlash, and he said no. Still, I believe that there must be some kind of active force on the thing over and above that of gravity and the seven foot water column. For a ball to accelerate that fast over a distance of two inches, some other force must be applied. I just don't understand the dynamics of the thing.
The valve is a LEGEND 1 200 W00 for 1 1/4" pipe. It was made in Taiwan. It is brass, threaded,
possibly model T-149, and it is eventually coupled to a PVC pipe. The 1/4" pvc outlet drops
about 7 feet.
Marvin E Walden
Troy, MI, USA
