I have a home that is only 6yrs old. One of the showers has very low water pressure. All of the other showers have the same delta shower head and valve and work just fine. I called delta and they told me to flush the water lines. I turned off the main water supply pulled out the valve and turned on the water. Tons of water pressure! Then I replaced the valve and did the same with the shower head. Significantly less water pressure. They told me to back flush the water so I turned off the cold water line going in to the water heater. Turned hot water on in faucet on my main level. plugged the shower head with a dime and turned on the cold water. no water came out of the faucet on the main level at all. What did I do wrong? I then checked the shower head and when the lever was barely turned on so that cold water only was running there is almost no water coming out when it is turned fully so that it mixes water comes out but obviously not enough water to back flush the line and empty out into the main level bathroom. Any suggestions? Could there be a problem with my water valve?

I would assume the cartridge is at fault. I would remove, disassemble and clean it.

That was the first thing I did. Surprisingly it was all pretty clean. So I called Delta customer service and the rest is in my last post. I still cant figure out why the water did not back flush back down and come out the faucet downstairs. Any ideas?

1. Was this a sudden problem? Was it working one day and not the next?
2. You mentioned you changed the valve, do you mean the shower cartridge or some other valve?
3. Have you unscrewed your shower head so it is just the open pipe and turned the shower on? If so, what happened?
4. Is this a shower only? Or is it a tub/shower combo? If it's a combo do you have water pressure at the tub spout?

So this is a shower only and I took the shower cartridge (not valve) out and flushed water thru the pipe where the cartridge sits then put it back together and flushed water out of the pipe where the shower head is. The water pressure has always been low in this shower. 6 months ago I tried buying a new shower head that had adjustable settings and it is no better. When I flushed water through the arm that holds the shower head the pressure very low especially compared to the pressure I got out of the pipe the cartridge sit in. Actually it is so low that when I turn the cartridge to start cold water only it barely comes out. It is not until I turn it to full hot that I get a little more pressure but still not enough.

By disassembling the cartridge, I mean actually separating it half,(after pulling it from the valve body) and removing the balancing spool and cleaning all interior sections.

Pull the trim plate off of the shower valve, you might have small stops on the shower valve body that aren't in the full on position.

As mentioned above, either disassemble the cartridge and clean it, or replace it entirely.

Do the other fixtures in this bathroom have low pressure?

Thanks for all of the replies I actually did disassemble the cartridge and it was really clean but I cleaned it anyway. I ordered a new cartridge and I will see if that works. Delta customer service said It is probably not the cartridge and I need to back flush the pipe starting at the shower head and I tried that with no success.(Actually I am not sure why it didn't work I tried the plugging it with a dime trick that is posted everywhere online) but..... Hopefully the new cartridge works! Thanks for all of the help!



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quote; They told me to back flush the water so I turned off the cold water line going in to the water heater. Turned hot water on in faucet on my main level. plugged the shower head with a dime and turned on the cold water. no water came out of the faucet on the main level

You CANNOT do that. The pressure balancing cartridge will NOT allow ANY flow. (even backflow), if the hot water heater, (or the cold supply for that matter), is turned off.