Over 698,000 strictly plumbing related posts
Plumbing education, information, advice, help and suggestions are provided by some of the most experienced plumbers who wish to "give back" to society. Since 1996 we have been the best online (strictly) PLUMBING advice site. If you have questions about plumbing, toilets, sinks, faucets, drains, sewers, water filters, venting, water heating, showers, pumps, and other strictly PLUMBING related issues then you've come to the right place. Please refrain from asking or discussing legal questions, or pricing, or where to purchase products, or any business issues, or for contractor referrals, or any other questions or issues not specifically related to plumbing. Keep all posts positive and absolutely no advertising. Our site is completely free, without ads or pop-ups and we don't tract you. We absolutely do not sell your personal information. We are made possible by: 
|
|
Author:
DIYHomeOwnerNC (NC)
A few seconds after the flush tank (on either floor) starts to fill or if the shower is turned on, we hear a big thump and when the water use stops (flush tank fills or shower turned off) we hear a small thump. The thump is heard coming from the wall between our master bathroom and the water heater.
I put a pressure regulator on the spigot and saw the static pressure is ~55 psi. When the flush tank starts to fill the pressure slowly drops to ~25 psi (in 4-5 seconds) and I hear the big thump. The pressure stays low until the water is flowing and then starts to build back up (the small thump). This makes me wonder that maybe a check valve somewhere is closing and opening when the line pressure is too low, etc but I don't know where it could be (maybe from the water heater).
So now I am thinking the problem is not the thumps but the low flow causing a drop in line pressure. Something somewhere may be restricting the flow coming in
The one thing I may try is turn the screw on the Apollo 36C 3/4" pressure regulator to increase the static pressure and see if the pressure fall off stays above lets say 30 psi and if that prevents the thump.
Any other suggestions?
Information:
City water supply
7 year old home
3/4" line coming in with PRV in first floor garage
No basement
Second floor water heater has an expansion tank
|
|
Post Reply
|
|
|
Author:
North Carolina Plumber (NC)
I would investigate the pressure reducing valve first, they are notorious for causing sounds throughout the piping system. If you have a thermal expansion tank near the water heater you might check the air pressure in it also.
|
|
Post Reply
|
|
|
Author:
DIYHomeOwnerNC (NC)
Thank you for the reply.
Had not thought about checking the air pressure in the expansion tank. At this very moment I don't know how exactly to do that but I am sure there is enough help available online.
What do you mean by the PRV being notorious for causing sounds throughout the piping? The thumps I hear are on the second floor and the PRV is on the first floor.
Edited 1 times.
|
|
Post Reply
|
Please note:
- Inappropriate messages or blatant advertising will be deleted. We cannot be held responsible for bad or inadequate advice.
- Plbg.com has no control over external content that may be linked to from messages posted here. Please follow external links with caution.
- Plbg.com is strictly for the exchange of plumbing related advice and NOT to ask about pricing/costs, nor where to find a product (try Google), nor how to operate or promote a business, nor for ethics (law) and the like questions.
- Plbg.com is also not a place to ask radiant heating (try HeatingHelp.com), electrical or even general construction type questions. We are exclusively for plumbing questions.
Search for plumbing parts on our sponsor's site:
Special thanks to our sponsor:
