I had very low water pressure coming out of my bathtub spout and the shower diverter was faulty so I removed the spout. The pressure was low coming out of the 1/2 inch copper pipe.

I then replaced the Moen 1222 single handle cartridge. It was extremely stuck and when I finally got it out the black silicone "plugs" on either side were stuck inside the supply lines on each side. I removed the silicone, used CLR and flushed the line. Water shot out like a fire hydrant!

I installed a new cartridge and again had almost no water pressure. I purchased another cartridge in case it was faulty, tried blowing out the pipe installed the new cartridge and was back to the initial low pressure out of the tub spout that I started with. After soaking and cleaning my tub spout I reinstalled it and could not get water to go up to the shower.

I have a new spout to install but am hesitant because my water pressure is still so low. Since it shoots out without the cartridge I feel something must be stuck between the valve and the drop pipe to the tub. As far as I can tell the valve does not look to have any corrosion. There is just one very small hole in it that could lead to the tub spout and I'm wondering if it is too small of a hike or if something is just stuck in there?

  • What method do you use to divert tub spout flow up to the shower, a valve integrated into your tub spout, or a lever or button integrated into the shower valve unit? Nov 20 '20 at 21:01
  • Did the water pressure drop suddenly or did it drop slowly over time?
    – HoneyDo
    Nov 20 '20 at 21:18

I've dealt with a few very similar problems.

I'm not sure what you mean by very low water pressure but assuming it's not a low-flow valve the problem is a blockage between the valve and the faucet. If this happened slowly over time it's probably the result of corrosion/calcium buildup in the supply line from the valve which can be cleared with CLR or another decalcifying agent and flushing. However, I have the impression that this happened fairly suddenly. If so, what probably happened is that pieces of the black plugs you decscribed broke off and are lodged in the supply line between the valve and the faucet.

Usually when this happens the pieces flow through and are caught in the faucet strainer - but I'm assuming you checked that. Since that didn't happen your best bet is to remove the valve and the faucet and try to funnel some CLR or other cleaning agent down the supply line from the valve. I would then run a narrow flexible cable down the supply line from the top and up through the outlet at the spout end to try to break up and dislodge the debris. It will require some patience but 1/2 inch copper is large enough that it shouldn't be clogged too tightly.

I should also mention that the probable cause of the diverter not working was the low water pressure. Most diverters require a certain level of water pressure to engage and hold the gate diverter open.

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