Humming sound at the water pressure gauge when the water comes into the house

shop deals on amazon
Advertise with us
Support your community
Shop deals on ebay
Plumbing Forums

Help Support Plumbing Forums:

This site may earn a commission from merchant affiliate links, including eBay, Amazon, and others.
C

canyonsky

Member
Joined
Nov 23, 2013
Messages
12
Reaction score
1
Location
,
Our house was built in 2018. We have municipal water. For a couple weeks we've noticed a continuous humming sound from the water pressure valve area (pressure gauge--see photo marked in red) when we partially turn on the faucet and run the cold water. The noise ends when we stop the water flow. However, sometimes there's no humming noise if the faucet is barely turned on. For a couple days I've noticed the short hum right when we fully turn on the faucet. There's no continuous noise when water is running fully.

Today, the water pressure reading before and after flushing a toilet and washing hands were 56; 1.5 hours after doing dishes and taking a shower it was 56. Usually after we use hot water for doing the laundry or taking a shower, the water pressure could be around 70-80. One day it was at 100 after hot water laundry. Our A.O. Smith water heater has an expansion tank and sometimes it discharges water when we take bath or long hot showers. The T&P relief valve was replaced about 2 years ago when extensive water discharged from the tank after frequent hot water bathes due to leg pain. A.O. Smith recommended the replacement.

What went wrong? Should we lower the water pressure to get rid of the humming noise?

Thanks you.
 

Attachments

  • Water_Pressure_Gauge.jpg
    Water_Pressure_Gauge.jpg
    46.1 KB · Views: 0
Last edited:
I suspect you have two problems.

One, the humming is likely caused by a faulty PRV. Mineral buildup can cause flow issues inside the valve and cause the PRV to "sing".

Two, if there is a valve to isolate the expansion tank and it isn't closed, the diaphragm in your expansion tank may have failed and the tank is likely full of water.
 
MicEd69 said:
I suspect you have two problems.

One, the humming is likely caused by a faulty PRV. Mineral buildup can cause flow issues inside the valve and cause the PRV to "sing".

Two, if there is a valve to isolate the expansion tank and it isn't closed, the diaphragm in your expansion tank may have failed and the tank is likely full of water.
Click to expand...
This is a great answer. PRV'S are a valve that open and close to control water pressure. They can chatter when failing. For the expansion tank it sounds like you will experience one of two things. First get your keys and go to the expansion tank and find the Schrader valve (little nipple like a car has on its tire). Press down on it. If it's failed you will experience one of three things. A small amount of air coming out, no air, or water. If you have a tire gauge you can check it's pressure and it should be a few psi higher than your incoming water pressure.
 
Thank you all for your response. We pay more attention to the source of the noise. It's the water pressure gauge when the water comes into the house (please see the photo marked in red). We lower the water pressure and the noise remains when we turn on cold water. Should we replace the gauge or is it still the expansion tank problem? Sorry for the confusion.
 

Attachments

  • Water_Pressure_Gauge.jpg
    Water_Pressure_Gauge.jpg
    46.1 KB · Views: 0
Last edited:
Is this something we can do ourselves? If yes, I think we need to shut off the water main valve, release the water, and then replace it. Also recommendation of a high quality gauge will be highly appreciated for we don't want to replace it every six years.

Any advise or instruction is welcome.

Thank you!!
 
Twowaxhack said:
It’s a guess……just replace it and see what happens.
Click to expand...
Is this something we can do ourselves? If yes, I think we need to shut off the water main valve, release the water, and then replace it. Also recommendation of a high quality gauge will be highly appreciated for we don't want to replace it every six years.

Any advise or instruction is welcome.

Thank you!!
 
canyonsky said:
It's the water pressure gauge when the water comes into the house (please see the photo marked in red).
Click to expand...
I highly doubt that the noise is caused by the pressure gauge. It may sound like it is coming from there, but it would be far more likely that it is the PRV itself.

But yes, you can change the gauge yourself if you want. Or you could remove it totally and plug the connection, which may be the initial route you would like to take. Many PRVs do not have a pressure gauge. Then, if that solves the noise, you can install another gauge at a later date. If it doesn't resolve the sound, then you will need to replace the PRV, which you can also do if you are comfortable with piping and you get the exact same PRV.

I assume the valve just below the PRV is the incoming water. Close it and open the lowest and highest cold-water faucets to drain as much water as you can from the water lines. Then, simply remove the pressure gauge and install a plug or the new pressure gauge. Some water will come out when the gauge is removed. I use pipe dope that is acceptable for potable water rather than Teflon tape, but many just use tape.

If you need to replace the PRV, just get the same model, drain the most water you can as mentioned above, remove the upper and lower unions, remove the nipple from the top of the old PRV and install it on the new PRV, then install the new PRV assembly tightening the two unions. Use pipe dope, or Teflon tape on the nipple connection, but nothing is used on joining the two unions.

The PRV likely has a check valve such that water cannot flow back to relieve any pressure caused by the water heater heating water and expanding the water volume which increases the pressure in the water lines if the pressure tank is not functioning properly.

See Adam F's post #4 above for instructions on how to verify a proper functioning pressure tank. That should be your first step to see if that is the pressure problem due to the water heater. I'm betting it definitely is.
 
You can’t check the pressure of an expansion tank with an air pressure gauge without turning water off and relieving the residual pressure on the system.
 
MicEd69 said:
I highly doubt that the noise is caused by the pressure gauge. It may sound like it is coming from there, but it would be far more likely that it is the PRV itself.

But yes, you can change the gauge yourself if you want. Or you could remove it totally and plug the connection, which may be the initial route you would like to take. Many PRVs do not have a pressure gauge. Then, if that solves the noise, you can install another gauge at a later date. If it doesn't resolve the sound, then you will need to replace the PRV, which you can also do if you are comfortable with piping and you get the exact same PRV.

I assume the valve just below the PRV is the incoming water. Close it and open the lowest and highest cold-water faucets to drain as much water as you can from the water lines. Then, simply remove the pressure gauge and install a plug or the new pressure gauge. Some water will come out when the gauge is removed. I use pipe dope that is acceptable for potable water rather than Teflon tape, but many just use tape.

If you need to replace the PRV, just get the same model, drain the most water you can as mentioned above, remove the upper and lower unions, remove the nipple from the top of the old PRV and install it on the new PRV, then install the new PRV assembly tightening the two unions. Use pipe dope, or Teflon tape on the nipple connection, but nothing is used on joining the two unions.

The PRV likely has a check valve such that water cannot flow back to relieve any pressure caused by the water heater heating water and expanding the water volume which increases the pressure in the water lines if the pressure tank is not functioning properly.

See Adam F's post #4 above for instructions on how to verify a proper functioning pressure tank. That should be your first step to see if that is the pressure problem due to the water heater. I'm betting it definitely is.
Click to expand...
Thank you for the detailed explanation and instruction. Now I understand better about the expansion tank for we've never had one for our water heaters in prior homes for decades. We will test Schrader valve and I guess if the tank is still good we should get a lot of air(?)...because "If it's failed you will experience one of three things. A small amount of air coming out, no air, or water."
 
Twowaxhack said:
You can’t check the pressure of an expansion tank with an air pressure gauge without turning water off and relieving the residual pressure on the system.
Click to expand...
Can I use a key to press down on Schrader valve without turning water off and relieving the residual pressure on the system?
 
canyonsky said:
Can I use a key to press down on Schrader valve without turning water off and relieving the residual pressure on the system?
Click to expand...
Yes, I suspect with the symptoms you described, you will be seeing water come out of the valve. Do that first, and if you have water, that indicates the diaphragm has failed.

If air comes out, you can check the air pressure which should be the same as the water side pressure. But to set the pressure with a compressor, you will need to remove the water pressure on the plumbing side of the diaphragm.
 
Last edited:
I would like to add if anything except water comes out of the expansion tank you can try to tighten the valve or replace the valve. If water comes out replace the tank. I'm glad someone caught the the fact the water should be turned off and bled. Sometimes I forget to mention the basic things. 👍
 
Thanks for all you help. Here's the update.

Three weeks ago a plumber replaced the water pressure regulator right above the water main shutoff, the pressure gauge and the expansion tank (yes, it's filled with water), but the noise is worse now. It was like whining, but now is screaming when water pressure is set between 50-62 psi. The plumber refused to pre-charge the expansion tank to match the water pressure and said, "Trust me." After we pressed, he said our hot water heater size is below the max limit of the expansion tank.

He also had installed the initial pluming system for the house and raised the water pressure to about 57 psi after we moved in per our request. He had said that he hardly could adjust it higher anymore. But the new Boshart PRV (with water in the pressure gauge) he replaced was preset to 60 psi and he even didn't test it with the expansion tank prefilled to 40 psi. He said the noise was just annoying, nothing to worry about. After we informed him of the worse situation, he wanted us to pay attention to the noise and wait for a couple of weeks and then call him again. We're not sure if we should.

We have been trying to lower or increase water pressure to see whether it makes difference. If we raise the water pressure close to 60, 60,or 62 the noise became almost non-noticeable the first time we used the water as usual. But from the second usage on, the loud noise returned. Except the onset noise when we use the water, the ending louder noise kicks in about 10 seconds after the water is turned off or the toilet tank is refilled. And noise lasts 10-20 seconds.

We observed some differences: 1) after several hours not using the water, the screaming is the worst--long and loud (scale of 10); 2) outdoor faucets generate least noise: whining at onset only (scale of 2); 3) filling up one cup of water from the kitchen faucet doesn't cause any noise, but washing veggies or dishes for a longer period of time generates the longest and worst screaming (scale of 10) for 15-20 seconds after the faucet is shut off; 4) flushing a toilet causes an onset whining (scale of 5) and after the tank is filled noise at scale of 7 lasts about 10 seconds.

What else can we do? Is this noise common? What causes it? What brand makes the highest quality of water pressure regulator?

Thank you in advance.
 
Last edited:
The expansion tank should be charged to the set point of the pressure reducing valve.

This adjustment to the air charge must be done while the water is off to the tank and the residual pressure has been relieved from the system.
 
I would not use that plumber again, his excuses don't make sense to me. How old is the PRV? What is the pressure without a PRV?
 
The PRV is installed on 8/7 this year. We just charged the expansion tank. The noise is reduced dramatically now and sometimes we don't hear it. We will keep listening. Fingers crossed. Thank you!
 
You must log in or register to reply here.

Latest posts

Back
Top