Is my hammer arrestor working properly?

Joshuam08

Hi all, we've had an ongoing issue with hearing thuds (no vibration or rattling but basically I can hear that the washing is running when it does this from almost anywhere in the house) from our pipes when our washing machine is running, mostly during the periods where it rapidly opens and closes the valves. We dealt with this mostly by turning down the water pressure, but this was causing laundry powder to not be fully dispensed from the drawer.

So today I decided to go buy a hammer arrestor. I've installed arrestor and from what I can tell I can no longer hear the water line thudding around the house, however there is still thudding in the laundry (unsure if it is coming from the washing machine valve side or the arrestor), but google is telling me that an arrestor should be quietly dampening the pressure shock. Does this sound normal or does it sound like the arrestor may be faulty?

https://www.bunnings.com.au/20mm-hydrarester-washing-machine-dishwasher-chrome-size-a-water-hammer-arrestor_p0708209

Thank you!

EricL

Hello @Joshuam08

Please note that plumbing work needs to be completed by a licensed professional for safety and compliance.

Thank you for sharing your question about your hammer arrestor. It sounds like you've already made some good progress with the issue. Based on your description, the hammer arrestor appears to be doing its primary job, as the loud thudding that could previously be heard throughout the house has now been eliminated. That's typically a strong indication that the water hammer effect travelling through the plumbing system has been significantly reduced.

That said, it isn't unusual to still hear some level of thudding or clicking within the laundry itself when a washing machine rapidly opens and closes its inlet valves. Modern washing machines can pulse the water supply very quickly during certain cycles, and while a hammer arrestor absorbs the pressure shock in the pipework, it doesn't necessarily make the valve operation completely silent. A small, localised noise near the machine or arrestor can be considered normal, particularly if the sound is no longer being transmitted through the house.

If the remaining thud is still quite pronounced, there are a couple of possibilities worth considering. The arrestor may not be positioned as close to the washing machine valve as ideal, the plumbing supplying the laundry may still have some pipe movement where pipes are not fully secured, or in some cases the washing machine's own inlet solenoid valves can create a noticeable mechanical knock when operating. A faulty arrestor is certainly possible, but if the whole-house noise has disappeared after installation, that would generally suggest the arrestor is functioning rather than failing.

I'd recommend monitoring it over the next few wash cycles. If the noise remains confined to the laundry and there are no vibrations, rattles, leaks or renewed pipe hammer elsewhere in the home, there's a good chance what you're hearing now is simply the normal operation of the washing machine and arrestor combination rather than an indication of a fault.

Hopefully you've already solved the main issue and what remains is just a much more localised sound. It certainly sounds like you're heading in the right direction, and it's great to hear you've been able to restore your water pressure while reducing the pipe hammer throughout the house.

However, should you wish to investigate further, I suggest engaging the services of licensed plumber. They will be able to assess your plumbing in a much more comprehensive manner and possibly offer other solutions to the pipe hammer.

If you need further assistance, please let us know.

Eric