Demo'ed shower, need help with mystery pipe

Users who are viewing this thread

taz1811

DIY virgin
Messages
12
Reaction score
0
Points
0
Location
Washington DC
Hi, I just demo'ed my basement shower and need some advice because I want to install the Moen 3520 valve. I'm curious which pipe is hot/cold? When I turn the faucet left it gets hot; does that mean the right pipe is hot water? Also, what is the pipe going down and turning left into my wall...and why is it only attached to one side? (I'm assuming it's attached to the cold water pipe? Could this possibly be feeding my outside hose?


51QHXbzzQLL._SX385_.jpg

DSCF0046.jpg

DSCF0047.jpg

DSCF0049.jpg
 

Jadnashua

Retired Defense Industry Engineer xxx
Messages
32,771
Reaction score
1,191
Points
113
Location
New England
Usually, the cold is on the right and that T'ed line could go anywhere. But, many shower valves can be plumbed with the water swapped and then compensate by either flipping the cartridge or removing the handle and rotating the stem 180-degrees. The simplest way to tell which pipe is hot or cold is to turn it on! You may want to hold a bucket to catch the water coming out of the shower riser. instead of it splashing everywhere. You'll be able to feel which pipe gets hot after running a minute or so. This assumes you can't easily trace the piping back to a known branch.
 

taz1811

DIY virgin
Messages
12
Reaction score
0
Points
0
Location
Washington DC
Usually, the cold is on the right and that T'ed line could go anywhere. But, many shower valves can be plumbed with the water swapped and then compensate by either flipping the cartridge or removing the handle and rotating the stem 180-degrees. The simplest way to tell which pipe is hot or cold is to turn it on! You may want to hold a bucket to catch the water coming out of the shower riser. instead of it splashing everywhere. You'll be able to feel which pipe gets hot after running a minute or so. This assumes you can't easily trace the piping back to a known branch.

Thank you for the response.

So when I get the Moen 3520 valve, would I solder a plug into the botton opening? What is the bottom opening generally used for?
 

Terry

The Plumbing Wizard
Staff member
Messages
29,946
Reaction score
3,460
Points
113
Location
Bothell, Washington
Website
terrylove.com
Run water from the old valve. What ever side gets warm comes direct from the water heater. Mark that pipe hot.

The four port Moen valve is hot and cold on the sides, preferably hot on the left.
The top is for a shower, the bottom for a tub. That can be capped if not used.

The mystery pipe may be feeding something like a toilet nearby.
 

JohnfrWhipple

BATHROOM DESIGN & BUILD
Messages
3,225
Reaction score
102
Points
48
Location
North Vancouver, BC
Do you have a pressure balancing valve in your home? We like to have the outside water line piped BEFORE this PRV or pressure reducing valve. This way you get more coverage because the sprinkle has more water pressure and goes higher!.

I bet it is like Terry mentioned and for the toilet.

What kind of toilet do you have? I would disconnect the flex line from the toilet and flush this line before using it after the new plumbing work is done. Also get your plumber to remove the cartridge and flush the old lines before testing the shower head. Simple step that could save you a trip or two to the plumbing wholesaler.

JW
 

taz1811

DIY virgin
Messages
12
Reaction score
0
Points
0
Location
Washington DC
Do you have a pressure balancing valve in your home? We like to have the outside water line piped BEFORE this PRV or pressure reducing valve. This way you get more coverage because the sprinkle has more water pressure and goes higher!.

I bet it is like Terry mentioned and for the toilet.

What kind of toilet do you have? I would disconnect the flex line from the toilet and flush this line before using it after the new plumbing work is done. Also get your plumber to remove the cartridge and flush the old lines before testing the shower head. Simple step that could save you a trip or two to the plumbing wholesaler.

JW


Okay, will do. Thank you. Yes. You guys are most likely correct, I have a toilet behind that wall which I completely forgot about.
 
Top
Hey, wait a minute.

This is awkward, but...

It looks like you're using an ad blocker. We get it, but (1) terrylove.com can't live without ads, and (2) ad blockers can cause issues with videos and comments. If you'd like to support the site, please allow ads.

If any particular ad is your REASON for blocking ads, please let us know. We might be able to do something about it. Thanks.
I've Disabled AdBlock    No Thanks