Tough Plumbing Question - Low Cold Water Flow

[DallasCoon12]

I would take out the single handle cartridge and the cold stem and inspect carefully for debris. Get some help and turn the water on for a few seconds with cartridge/stems out to blow any debris out. Possibly replace cartridge/stems.

[Wits_End]

Thanks for the suggestions, I am being convinced this is multiple issues and not a single source. I'll disassemble some things today and see if somehow debris is causing this. The shower was always there, but it was demo'd and reconfigured. Lines were simply routed closer to the entrance of the shower and dual shower heads were added. The existing copper was cut and then pex was added for the reroute and new lines. The shower assembly is a single handle valve/mixer combo.

Ill try to explain what i know about the plumbing. The tub and shower somewhat share a wall. I can see the tub pipes coming from that wall and they are 3/4" copper or so, i can't see where the pipes come up through the slab as it is behind a stud. On the opposite side of that wall i can see the shower pipes and they are 1/2" copper, again I can't see where it comes up from the slab because it is behind another stud. It is the exact same area the tub lines come from. I would have to cut sheetrock to get to it.

The tub has a faucet handle for hot and separate faucet handle for cold. They then combine together after the handles and go to a straight through spout. Each of the lines has a shutoff valve right before the handles.



Also, I have an office that shares the shower's back wall and in the office is a small wet bar sink. It also has very low cold water flow. The pipes for that sink come up from the slab in 10ft away from the other pipes, they are also copper. It is a dual handle sink, hot works fine. I have already checked the aerator for debris.

[Wits_End]

Tub lines

[Hammer-1]

Did this problem just start orhas it always been low pressure?
I would start at the cold water shut off valve. Sometimes you can get lime buildup or possibly soldering has gotten into the valve,restricting flow. Did you make shur the valve is open all the way?


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[Paycheck]

Good luck. I like to flush with water if possible. Wash the debris out. If it was the hot side I would suggest kill valve at water heater disconnect hot water like, put hand over tub spout and turn both cold and hot on. You might can find away to do this with the cold water.

[Wits_End]

Alright, making progress. I couldn't convince myself this was a multiple faucet problem, but I'm forced to believe it now.

It's hard to get your head and hand for that matter in to the tub shutoffs. I reached in and verified it was all the way open and it was hard stopped that direction. I went to shut it off and it hard stopped the other direction in 1/2 turn, which wasn't right. After a better picture I could see it wasn't opened all the way. I grabbed some channel locks and broke it free and fully opened it. The tub now has great cold flow.

I skipped to the wet bar sink, shut off the cold side, removed the cold water flex hose from the faucet, then opened the valve and I had great water flow into a bucket. Messed with the faucet some, but it is bad. I will be replacing the faucet to fix that one.

Now on the shower... I may need to shut the house water off to work on this. Now that this is the only problem, it should be easier. I'll verify I opened the local valve shutoff all the way first.

[Wits_End]

Well gosh dang. I would have bet everything I had that this was not three independent problems and it was. What are the odds a faucet cold side goes bad, a cold tub shutoff gets stuck, and a operator failure to fully open the shower cold diverter stop? All in the same area of the house, all on the cold side.
For the shower I guess I was worried about unscrewing the diverter stop all the way out as it became very loose and I was afraid it would just fall out, but after looking at the drawings, it is suppose to be all the way out.
I know I checked numerous times that tub valve to ensure it was all the way counterclockwise, but never tried to shut it off and reopen so I didn't notice it was getting stuck at only 1/2 turn open.

Fully functional now, well besides needing a new sink faucet. I appreciate all of the help, your idea definitely pushed me to just start somewhere.

[chocolatelabs]

Those are gate valve and they are notorious for not opening up all the way.

Even if they are working now I’d replace them with ball valves

[StrayDog]

Glad it worked out. If a professional soldered that copper pipe they need some serious practice/instruction. If thenvalve that was sticking was soldered it’s probably internally damaged from the same soldering job.

Honestly, I’d replace that soldered section you posted a picture of and the valves you can reach. Just use shark bite fittings and it’s easy peasy. Those crappy solder joints are just waiting to fail.

[Wits_End]

Agree with you guys. I am up to my ears in repairs and remodels, but will definitely add it to the list as must do. Looks like ill just cut that entire 90/valve section out and replace with sharkbite/pex. The house was a foreclosure and sat vacant for 18 months. That and the lack of history complicates each piece.