Water hammer hot water only

[mattster1975]

Hi - have severe water hammer with the hot water only. It's worst with the LG washing machine (even with a mini-restor at the appliance). We get it if we turn off a faucet too hard too.

Do we need to bite the bullet and just open up the ceiling and secure the pipes? Can a pressure reducing valve or expansion tank help (we have neither).

The problem seems worst in the winter when the water coming into the house is colder.

thanks!

 

[Reach4]

I wonder if your mini rester went bad. Perhaps try another, or consider two in series.

Is this an older house? Maybe you have the older type of hammer arrestor at the faucets. Those were just some dead-end vertical pipes. Consider turning off your water and opening your highest and lowest faucets to drain the water out of yours.

An expansion tank might help. Not sure.

This one fits on a 3/8" shutoff.

 

[Sponsor]

 

[Master Plumber Mark]

you are screwed...i got one of those stupid Lg units and they jet water into the machine constantly and the pipes at the other end of the house vibrate and shake the shit out of everything... I got a prv valve in the line and I got the thermal expansion tank too.....


I suggest on top of your water heater to install the thermal tank anyway, but on both the hot and cold lines going to the heater Install a couple of air chambers probably about 24 inches long with caps on the end.. the longer the better .they are supposed to arrest the water hammer

 

[Terry]

An expansion tank won't help the hammer.
Hammer arrestors help. Some water heaters used to come with ball checks in the nipples at the top of the tank. If you have those, removing and replacing with non-checks helps.

 

[mattster1975]

I can hear where the hammer happens. Does securing the pipes help at all? The hammer comes from right under the 2nd floor water heater so breaking open the ceiling and securing the pipes would be messy and expensive, but doable. Does securing the pipes help at all?

Would installing a pressure reducing valve at the hot water heater help?

 

[Terry]

The water pressure in the home should be 80 PSI or less.
What is your current water pressure?

 

[mattster1975]

It was 60 PSI at the hose bib the last time I checked (when I installed the Watts arrestor a year or so ago). I can check again - my neighborhood has boster pumps to keep pressure higher and consistent.

Can the hot pressure be higher b/c of thermal expansion of the water?

 

[mattster1975]

Ok - just got the new pressure gauge and the static pressure was 68 PSI at the hose bib.

Would a pressure reducing valve possibly help?

 

[Master Plumber Mark]

68 psi is pretty mild--wimpy that is a good pressure.....

wait until tonight and attempt it again...sometimes it spikes in the evening

You SHOULD secure the pipes and it will probably solve your issues if you only
have 65 psi in the home... they are just neeeding bolted down