Water hammer issue

[Tom2rn]

I just recently installed a 50 gallon water heater in my garage. I had a low boy in the crawlspace and decided I'm too old and fat to keep climbing under there. A plumber friend from work (I work at a hospital) helped me. We added a recirculation line. I insulated the recirculation and regular hot water lines. I made sure no pipes rubbed together. The house was plumbed with copper. We ran PEX and connected to the copper. The PEX was secured with good clamps every other joist. We have a thermal expansion tank and one way valves installed. The only thing we don't have is a relief valve on those lines. I am also on a well with a expansion tank under my house. After all was said and done I now have water hammer. My TOTO toilet upstairs and washer solenoids are the worst offenders. It even rattles the lines in the wall coming from upstairs. It did not do this before this job. What the heck? How do I solve this? Add arrestors to my washer supply? I don't understand why it happened in the first place.

 

[Jeff H Young]

what could you have done to the cold water systemto cause hammer at toilet? add hammer arestors at wash machine.

 

[Sponsor]

 

[Reach4]

I now have water hammer.

Do you get a single bang when the toilet shuts off or washer solenoid closes?

 

[Tom2rn]

This is the funny thing. I would think since I over secured all the piping, padded, We added the water heater and some 3/4" PEX on the cold and hot water lines. We used 1/2" PEX for the recirculation line. None of this occurred before the new heater. I did not have a recirculation line before this new system. I have one bang with each closing of the washer solenoid and one once the TOTO upstairs closes and fills. It only happens with my upstairs TOTO, not my downstairs one. I also have a standard toilet in the same bathroom as the washer and it doesn't cause this issue. I think I will get some arrestors on Amazon (Sioux Chief) and give them a try. Best to place them on the back of the washer or directly to the water inlets? I just wonder if my adding the recirculation pump has added some additional pressure in the system overall and is causing this. I need to cut the pump off and try it (this thought just crossed my synaptic junctions).

 

[Jeff H Young]

I think something else is going on you could cap off your circ line, I kind of hate to do things that don't make sense my w/c made hammer and changing the diaphragm or fill valve assembly fixed it. The first thing I do is check pressure that's a huge 9 dollar investment in a gouge no diy'er ever wants to make.
Somehow does your water travel a longer distance now that you relocated the heater? longer distances through small pipe and smaller fittings can cause more pressure drop and increase water hammer possibilities. But see no reason why the cold side is affected
I would try a repair kit for fill valve or new fill valve . And install aresstors on valves at wall for my wash/mach because my plumbing code requires it anyway.

 

[Tom2rn]

I think something else is going on you could cap off your circ line, I kind of hate to do things that dont make sence my w/c made hammer and changing the diaprahm or fill valve assembly fixed it. The first thing I do is check pressure that's a huge 9 dollar investment in a guage no diy'er ever wants to make.
Somehow does your water travel a longer distance now that you relocated the heater? longer distances through small pipe and smaller fittings can cause more pressure drop and increase water hammer possibilitys. But see no reason why the cold side is affected
I would try a repair kit for fill valve or new fill valve . And install aresstors on valves at wall for my wash/mach because my plumbing code requires it anyway.

Yes, it does travel a bit further now. Say 30' on each 3/4" PEX. Probably 50' with the recirc line. I have ordered some Sioux Chief arrestors for my washer. I will most likely replace the fill valve repair kit next on the toilet. If it still persists I will try a mini arrestor under the toilet. I will check my pressure also when my plumber friend comes by.

 

[Reach4]

I will check my pressure also when my plumber friend comes by.

There is a pressure gauge at your well pressure switch. If that is under the house, not so handy. But is is unlikely that you have high pressure in your house.

Do you know what pressure that is set for? While you are thinking of it, it would probably be a good idea to check your air precharge on the pressure tank -- not that a low precharge is causing water hammer.

 

[Jadnashua]

FWIW, arresters work best when they are closest to the offending valve...I have mine on the WM (and, actually, the dryer, too, as it can do steam). That should also make the hoses last longer, too.

Toto uses a few different fill valves, depending on where the toilet is made. Most of those in the USA that are not dual flush, tend to use those from Korky. Korky valves don't usually cause a water hammer.

 

[Jeff H Young]

My 17 year old toto toilets might have come with corkys but those are long gone. When we build homes hammer arestors must be installed plumbing inspected befor the washer /dryer are ever installed. But of cource plumbed hundreds of homes with out any arrestors with hardley ever a problem. I wasent thinking but the well pressure probebly not that great. so here is my guess and its only a guess so dont worry but I think its related to long runs of small pex and the fittings which are even smaller. a lot of change of direction (90 degree elbows) dont help either just a theory of mine