Intermittent dripping in shower

[MichaelFL]

I have a problem with intermittent dripping from the master shower. I cannot find a solution to it. I live in Peoria, AZ. My house is new - only 4.5 years old. The builder installed Moen fixtures throughout it. The master shower has the Moen model Eva fixtures (model T2132ORB). The control is one handle that rotates counterclockwise to adjust the water temperature.


About 3 months ago the shower starting dripping. Numerous drips of water would come out of the shower head rapidly for 15-20 seconds. Then the dripping would stop - for 2 to 5 minutes. Then it would repeat. This process continued for several days, or weeks, and then would stop - for several days, or weeks. Then it would start again. This has nothing to with flushing the toilets or turning on any other faucets. I have no issues with any other fixtures in the house.


I disassembled the control handle and removed the valve. I inspected the valve and the pipes in the wall. Nothing wrong. I reassembled everything and the dripping continued.


I went to the hardware store and purchased a new Moen Posi-Temp valve (model 1222). I installed the new valve per the instructions. The dripping stopped - for 3 weeks. Then it started again. I pulled out the new valve, inspected it again, lubed it good with silicon lube, and reinstalled it. After a few days the dripping began again.


I called a plumber. Naturally, the dripping stopped 3 days before he arrived and was not occurring while he was at my home. As a result, he did not remove the valve. After hearing the description of the dripping, he could not give any real reason why it was occurring. He checked the water system at the house and found no problems. He also checked the water pressure (I am not on a well) and it was 75psi, which he said was within normal limits. The dripping started again after he left.


Then I called Moen. I explained the issue to them and, after consulting with their experts, they responded that they had absolutely no idea why this was happening.


I did extensive research on the Internet, to no avail. Some said that it could be excess water inside the shower head that is released over time after use. So I removed the shower head for an entire day. The dripping continued, the same routine, from the pipe coming out of the wall.


I am completely dumbfounded. I cannot find an answer to solve this issue. Neither can Moen or a plumber. Any help would be greatly appreciated.

 

[Terry]

What is your water pressure?

 

[Sponsor]

 

[MichaelFL]

Like it says in paragraph 5, the water pressure is 75 psi, which is within normal limits, according to the plumber.

 

[FullySprinklered]

The water pressure can climb way above 75# if your expansion tank is defective. That would happen after a shower or other big hot water usage.

 

[Reach4]

I called a plumber. Naturally, the dripping stopped 3 days before he arrived and was not occurring while he was at my home. As a result, he did not remove the valve. After hearing the description of the dripping, he could not give any real reason why it was occurring. He checked the water system at the house and found no problems. He also checked the water pressure (I am not on a well) and it was 75psi, which he said was within normal limits. The dripping started again after he left.

What is the water pressure during the dripping? Pressure gauges are cheap.

 

[Terry]

All shower valves will drip for about 35 minutes once the shower head has been used. It takes that long for the pipes from the shower head to the tub spout to completely drain.
If it's only a shower, then much less time to stop.

 

[MichaelFL]

Would the expansion tank issue and the 35 minute shower head dripping continue for days even when I am not home and on a trip? I have found it freshly leaking after returning from short vacations.
Also, then why has it not dripped like this for the first 4 years in the house?
I have never had a shower that continued to drip for 35 minutes after taking a shower.
Can the expansion tank be adjusted for pressure

 

[MichaelFL]

Would a water pressure gauge measure any pressure when the only thing to message is 20 seconds of drips?

 

[Reach4]

Temporarily hook the garden hose thread pressure gauge to a laundry faucet or the drain on the WH. The outside faucet may or may not be suitable for this purpose.

 

[MichaelFL]

Maybe I'm just slow... I did not see how the plumber measured the water pressure. I just assumed that the professional plumber that I paid over $300 to do some work at my home knew what he was doing. He also did not find anything wrong with the expansion tank. He pointed the tank out to me.

I have also read that water pressure that is too weak can cause leaking as the seals need a certain amount of pressure to seal properly.

 

[Jadnashua]

When he measured the water pressure, it wa a snapshot in time. You can buy a pressure gauge with a second, tattle-tale hand that will show peak pressure and instantaneous. If you have a closed system ( a check valve, often installed by the utility to protect others in your neighborhood) makes it closed. WHen you heat water, it expands. It will instantly raise the pressure unless there's something that can leak to relieve that pressure. In an open system, it just pushes back into the supply, but can't when it is closed. If everything is nice and tight, the pressure will easily get up to 150psi, where the safety valve on the water heater will open.

So, it's important to know what the peak pressure is as well as the static, instantaneous one. A static pressure above 80psi requires a reduction valve to lower it. Those also create a closed system, if you didn't already have one. Your static pressure says you either have a reduction valve, or the supply pressure doesn't require further reduction. It's good to install one and leave it for say 24-hours of normal use to see what's going on.

In a closed system, an expansion tank gives the expanding water a place to go when the WH runs without raising the pressure in the system and stressing valves and hoses and pipes.

 

[MichaelFL]

Based on the responses I have received, I have a few questions:

1. I hired a professional plumber who works for a large company that was hired by the builder to install all the plumbing in my home when it was constructed. He checked the system and found nothing wrong. He said the water pressure was 75 psi which is within normal limits. So, I need to buy the equipment and check the water pressure from various locations withing my home myself? What if I get the same reading? What if I get a higher or lower reading? How does that solve my problem?

2. If high water pressure is the suspect, then why did my shower not leak in the first 4 years that I have lived in this house? Can water pressure increase over time? Do brand new water expansion tanks fail after only 4 years?

3. If high water pressure is indeed the problem, then why are the showers in the other 3 bathrooms in my house, which use the exact same Moen valve in the control handles, not leaking too?

4. According to the City of Peoria, AZ website, the water pressure varies between 50-80 psi. Therefore, is 75 psi out of range?

 

[FullySprinklered]

Is this in the bathroom most distant from the water heater. Working on a theory.

 

[Reach4]

Nobody suspects t

Based on the responses I have received, I have a few questions:

Based trying to figure out the cause and then cure for your intermittent symptom, I have 1 question:
1. What is the water pressure during the dripping?

 

[MichaelFL]

This is the master shower. It is not a tub/shower combination. It is the same distance from the hot water heater as one of the back bedrooms which does not drip. There are no showers that are farther from the hot water heater.

Regarding the question about the water pressure during dripping, where would be the best place to measure the pressure? I doubt if you would get any reading at all at the shower head as the valve is off and only a few drops come out.

UPDATE...I made a mistake. I pulled the work sheet and receipt that I was given by the plumber and looked at it again. It states that the water pressure was 70 psi, not 75 psi. That is still well within the normal limits when the city reports that normal is between 50-80 psi.

FYI...since the shower has been dripping since the last plumber left (on October 2nd) I have a second plumber coming on Thursday to look at the shower and the valve. We will see what he discovers...

 

[Reach4]

Regarding the question about the water pressure during dripping, where would be the best place to measure the pressure? I doubt if you would get any reading at all at the shower head as the valve is off and only a few drops come out.

Temporarily hook the garden hose thread pressure gauge to a laundry faucet or the drain on the WH. The outside faucet may or may not be suitable for this purpose.

The best one is the one you actually use and read while the shower is emitting water when it should not be doing so. A peak reading gauge could help you not to have to run to read the gauge during the water coming out. Attempting to connect to the shower head would be fruitless.

 

[Jadnashua]

With no water running, the water pressure only changes in the house based on elevation changes...all readings should be identical IF they are at the same height. Otherwise, it will vary by 0.43#/foot of elevation difference, dropping as you go higher (say to the second story) or lower (if you measured in the basement, assuming you have one - not that common in AZ).

A single check on the pressure will not tell you what's happening all day, and especially right after you use a bunch of hot water. As the hot water in the WH is replaced with denser, colder water and then heated, it expands. That expansion, in the inelastic pipes, means the pressure goes up unless there's a place for that 'extra, expanded' water to go. In many places, the utility installs a check valve in your supply that will prevent water from pushing back into their system. This helps to prevent anything that might get into your water (say your hose is in a puddle full of dog poop and a pressure hiccup occurs) from contaminating the people around you. This creates a closed system, and requires an expansion tank to give expanding water a place to go. If your system is closed, that expanding water will either raise the pressure considerably or cause a valve that might work at 70psi to now leak. So, if you want to know the range of pressure, you can't just measure it once...you need to know what it is doing over time. A pressure gauge with a second, tattle-tale hand will show both the current and peak pressure from the time it was installed. Recommend you leave the gauge on for at least 24-hours. They're cheap, usually less than $20 and easy to screw onto a hose bib, or with adapters, many other places. Often, an outside hose bib or the supply to your washing machine are the easiest places to access.

 

[FullySprinklered]

I often see pressure issues show up as a running toilet at the farthest distance from the main. Upstairs at the other end of the house. Not sure why.

 

[Jadnashua]

I often see pressure issues show up as a running toilet at the farthest distance from the main. Upstairs at the other end of the house. Not sure why.

A toilet fill valve is a common 'weak' link in the home's supply system, and can leak as pressure rises above the maximum generally allowed (80psi). In fact, some are designed to do that, but the big name brands do not, but can if they're worn. Often, replacing an old toilet valve with a new one is when people start to notice their WH T&P valve starting to open...there's no more leak to hold the pressure down anymore.

 

[MichaelFL]

A POSSIBLE SOLUTION...

The second plumber came to the house. Results:
1. He said there is no problem with checking the water pressure at the hose bib outside. They have been doing this forever. It is common practice and widely acceptable. They even do it for new builds. Therefore, the building inspectors must agree with him. This plumber has been in the business for 35 years.

2. He also said never buy a Moen replacement part from a big box store (ie, Home Depot). Moen offers lifetime replacement on their parts - always call Moen for the parts. Even though the Moen "genuine" replacement part has Moen's name and logo all over it at Home Depot, it is not the same quality as the ones that Moen sends you directly. There must be something to this. He replaced my "genuine" Moen part from Home Depot with a part he got directly from Moen. You can turn the control knob on the shower now with just the tip of your little finger. My "genuine" Moen part never turned that easily. And, so far, no leaks.