Water hammer in middle of night

[AdamL]

Hello all,

I am looking for some advice on how to handle this. Three times now I have experienced what I sounds like water hammer coming from inside of my hot water heater. The first time it happened it created a leak in my 12 year old water heater. It has occurred twice now with the new water heater (both 40 gal atmospheric gas).

The water hammer has only occurred at around 6:00am, before we are out of bed, so no water was being turned on and off. We are on city water, no expansion tank (water heater guy did not see pressure rise as the new tank was heating up, was at roughly 75 psi), so I assume I have an open system. I do not know of any water hammer arrestors in the system.

The water hammer has happened 3 times in the last month, and never happened before in the two previous years we have been in the house. House was built in 2007, and has PEX throughout the house. Any ideas on what might be causing this, and what the fix would be? Note, I do live across the street from a retirement home, so it is possible they could have some big water use at that time, I have already checked their sprinkler systems, they were not use around the water hammer time.

Thanks for your help.

 

[Jacobsond]

I would get an expansion tank on there. Has the city put a check valve on your supply recently?

 

[Sponsor]

 

[Sylvan]

Check your toilets and see if you have a 400 A

 

[Terry]

Check your toilets and see if you have a 400 A

Or an icemaker.

Ice maker,

 

[Jadnashua]

FWIW, a water hammer is caused by water flowing, then abruptly stopping, causing the pipes to literally hit something.

Does this happen at the same time of day, or just 'at night'? That may lead you to something (or not!?).

Many utilities can see higher water pressures during some periods of the night when there is little use and they raise the pressure to refill the water towers. This is one reason why it's useful to get a water pressure gauge with a tattle tale hand and leave it on for at least 24-hours. Your 'normal' water pressure may be fine during the day, but still could become high at night. That can cause various things to happen that you may not experience during the day, like a toilet fill valve opening, or some other thing running, then shutting off, creating that bump in the night you hear.

 

[AdamL]

Thank you for the replies. I checked my toilets, I do not have that valve. I do have an ice maker. I've started turning it off at night to see if that eliminates it. Since it only has happened once every week or two it will take a while to see if that is the problem.

The sound has happened between 6:00 and 6:45am everytime so far. It it happens again I will go get one of the gauges. One of my thoughts was a big use/stop of water at the retirement home across the street was affecting my pressure.

Thanks again everyone.

Ice maker box with hammer arrestor.