NxStage Pureflow causing knocking pipes?

I’m a caretaker and we have been at home for a few weeks now. Everything is going great except the pureflow is driving me absolutely bonkers. When it’s running it causes the pipes on the other end of the house to knock (rattling back and forth). I can get it to stop by turning down the water on the toilet where the water line is connected but it’s literally me running back and forth trying to balance enough water for the pureflow to not shut off but not so much that the pipes rattle. This takes about 20 minutes each session. We do have a pressure regulator on the main line of the house and readings are good. This has never happened in the previous 6 years we have lived here. This only happens when the pureflow is running. I’ve spoken with nxstage a few times and they have had me make a couple adjustments to the pressure regulator on the back of the machine, doesn’t do anything, and recommend getting main line pressure regulator which we already have beyond that they keep saying it’s impossible that it’s the machine and to talk to my center. Talked to the center and they have never heard of this happening and just don’t know what to do besides recommending that we have a plumber come out. I’m not against this, it costs what it costs but like I said since it’s only happening when the pureflow is making a batch I can’t help but wonder if there is something wrong with the pureflow.

Figured I would ask here and see if anyone else has ever had this experience? Thanks

Glad you found us, Whynot64, and I’m sorry to hear that you are having such annoying plumbing issues with the PureFlow. I can see how that would drive you bonkers! You sound pretty handy, too–I don’t know that it would have occurred to me to turn the water down on the toilet. Since NxStage hasn’t been able to advise you on this (they can’t see your house or your plumbing), a plumber does make sense. I wonder (remember that I know NOTHING about plumbing) if there is a way to insulate or cushion the involved pipes, so they don’t rattle? If you don’t get an answer from fellow NxStage users here, please consider joining our Facebook group if you are on Facebook. LOTS of NxStage users there have been through every imaginable scenario and may be able to advise you. The group is at Home Dialysis Central Discussion Group | Facebook

I looked up knocking pipes on the internet and found this site that may have somethings to try.

Hello whynot64.
Have you tried installing a good quality water hammer arrestor close to the PureFlow. I suspect the PureFlow has valves which turn on and off regularly and this arrestor should help. Also, if you want to understand the problem a bit more go to (Stop Water Hammer Before It's Too Late - Gold Coast Plumbing Company).
Hope this helps.

A friend who is a nurse and worked for NxStage responded to my question about knocking pipes wrote me this:
“There are back valves to prevent water going backwards??? PF only requires 20 psi which is a normal tap flow so not sure??

Their nurse could talk to their NxStage nurse & they could escalate it to try & find a solution

Would be interesting to see what plumber says …clinic should pay for it.”

Thank you that will probably be the next step, just wanted to ask here to see if anyone else ever had this happen since knocking pipes wasn’t an issue we ever had before getting the pureflow

Called nx stage several times, not really helpful but yes a plumber is next