No Flow In Cold Pipe In Shower

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SFLman

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I'm hoping to get some advice about a shower that has stopped working completely. The shower was not used hardly at all for three years, except for maybe filling up a bucket of water every once in a while, or washing down a large item of some sort.

Some guests came recently and it was used every day for about three weeks. On the last day my guests were in the house, it quit suddenly and loudly. This shower does not have a tub. Here is more background:



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Not knowing what the problem was, I bought a new Delta stem unit RP 1991. I've been in touch with Delta customer service but none of that back-and-forth matters, because I was not understanding the problem.

There are two items that fit into the brass faucet tube. Furthest out is the stem unit, which the knob screws into, and the other part I'm guessing is a Water Temperature Regulator. In the photo below the water temp regulator is on the left, stem unit is on the right. I'm also guessing that, if there is only pressure on one side, the regulator shuts off the flow immediately and completely to guard against scalding people as they shower.

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With both pieces removed from the faucet tube, I have put the main valve for the house on 25%, and looked inside the faucet tube with a flashlight. I can clearly see that no water is flowing on the cold side, but plenty of water flows out of the hot side. In the photo below, the blue box on the right at the back of the faucet tube is for the cold water, the one on the left is for the hot.


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I have also used a flat head screwdriver and twisted the shut-off valve on the left (for the hot water pipe) all the way clockwise to shut it off 100%. I then turned the main water valve to the house completely ON. If everything was working right, cold water would be shooting forcefully out from the faucet tube. Instead, the only thing coming out of the cold water pipe is a slight hissing sound.

I removed and inspected the shut off valve for the cold water pipe to verify that it wasn't frozen shut. That would have been great, but no, that's not the problem.


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I saw a trick on Youtube where a guy twisted the angled-down pipe that the shower head screws onto so that it was pointing upwards, and then he poured CLR into the pipe. I removed the black rubber stopper of the cold shut-off valve and installed just the hexagonal brass part of the shut off valve. I twisted the shower head pipe upwards and poured CLR into the pipe, hoping that it would make its way down to the blockage. I did this twice yesterday, waiting for over an hour each time.

The CLR did not work. I turned the main value to the house on, again, with the hot water shut-off valve screwed down to off, and with the cold valve on the right of course 100% open because I had removed the rubber stopper. There was no water flow at all out of the cold pipe.

Any advice I can get on this problem would be greatly appreciated. There's no big rush since I have another working shower in the house. I'm guessing this problem was caused by not using the shower much over the past few years.
 
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oldognewtrick

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I had a similar issue a couple years ago, solution was open the wall and replace the valve. I couldn't find matching tile, so I got a contrasting tile and made a design we lived with until I gutted and remolded the bathroom.
 

SFLman

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Thanks for the reply.

Just to clarify, you had a blocked pipe and changing the valve fixed it?

I've searched youtube for video on how to fix a blocked pipe, and I'm not coming up with much.
 

SFLman

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Problem is fixed and I will update just in case anyone has the same problem and comes across this thread.

The cold pipe was not blocked, and the one thing I know for sure is that I do not understand how a shower valve works.

Anyhow, luckily you can fix something without understanding it.

I purchased two RP2090


shower valves and the problem is entirely fixed.

PICT0002.JPG


The Delta Faucet RP1991 STEM UNIT was not the problem, but I did buy a new one. In the new one the center hole was drilled off center, so since this is related I'll add that information "for the record."

After installing the new RP 1991 my Danco Replacement Cross Arm Handle would not attach evenly to the RP1991. The old one was even. I finally used a drafting angle and one of the escutcheon screws to determine that the center hole of the new RP1991 was not drilled correctly. Anyone who happens to buy the RP1991 should check it immediately to see if you have a bad one or not.

01 OLD GOOD.jpg02 NEW.jpg03 New Bad Uneven.jpg04 Find Even Surface.jpg05 Center Hole Drilled Correctly.jpg06 Center Hole Drilled Incorrectly.jpg
 
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