we, just bought a house and noticed a strange plastic pipe line going upfrom the laundry sink to the upstairs shower. when you run a bath there is no problem when you turn the shower on not all the water goes to the shower head some goes through this pipe and down into the laundry sink and runs down that drain.this is a terrible waste of water let alone hot water.why is it there and what can we do to fix it.this is a half duplex and over 30 years old

labman

Strange. I would start by stopping up the pipe and see how the shower works. If the shower works fine with more flow, I would cap it off for now. On the other hand, it could be something cobbled up to correct some problem with the shower. If so, you may have to rip up the wall to fix it right.

The laundry tub does have its own supply line?

I will be interested to see if Tom has ever seen anything like it.

speedball1

A few questions. Your bathtub and your shower. Are they separate fixtures or a tub/shower unit? This plastic pipe. What size is it and are you saying it connects to the shower raiser after the valve and before the shower head and that it runs down to the laundry tray and doesn't connect but drains into the sink? If so simply purchase a permanent cap in the correct size, some primer and glue and close that sucker off at the open end.
I've never heard of a set up like that. The only reason that I can think of is that for some reason they were attempting to bleed off some of the pressure to the shower head. Good luck, Tom

speedemon101

thanks for the replies. when you divert the water from the tub to the shower head that is when the water goes down this plastic tube and drains in to the laundry sink downstairs. the laundry sink has its own water supply hook up and drain. so when the shower head is on with hot or cold or both water water drains down the tube and goes down the laundry sink drain. our fixtures for the shower are you basic hot and cold taps with the faucet in the middle for the tub with the shower head diverter.

speedball1

Speedy,

I don't have a clue as to why someone would want to bleed off the water from the shower raiser and divert to the laundry tub, as I said, " The only reason that I can think of is that for some reason they were attempting to bleed off some of the pressure to the shower head."
But the one thing I'm sure of, you don't need it. Remove the pipe or simply cap it off at the laundry and use it for a conversion piece. Good luck, Tom