Fresenius K intermittantly blows the tubing from the back side of the checkvalve, this has occurred 3 times over the past month. No flow or valve errs noted. Things I have already done to rule out. Changed Checkvalve, tubing,V30, V29, Heat Exchanger, checked flows at drain, all pressures and UF output. Any ideas?

Which side of the check valve is blowing off? Uf or drain

It is blowing off the drain side. I have changed V30,V29 and the heat exchanger, plus checked the flow at the end of the drain hose looking for some type of blockage but it is still does it every few days.

Had the same problem one time. The drain hose had fatty build up all the way through it. I changed out the hose, never happend again. Also make sure the ext-pre rinse is enabled, so it wont build up again. Hope this helps.

I got the same problem but it is the H. Flow inlet pressure regulator was the problem.

I had an intermittant problem with hoses on the drain side blowing off. It turned out the water inlet pressure regulator(61) would sometimes stick open. I watched the pressure for a short time and it seemed ok, just when I was going to take the gauge out it became eratic and spiked to the input feed pressure. It would seem the input water leaked through the heat exchanger and pressurized the drain side.

Thanks for the ideas. I have checked the drain hose and it is clear. I checked the incoming pressure regulator and the pressure seems ok but since this is only happening very intermittantly I will keep it in the back with the gauge hooked up to see if it spikes.

For what it's worth, -I have found that many times, while checking the inlet press. regulator, that it will appear fine while in rinse mode for example -cycling up and down properly, - but if the rinse cycle is interrupted and the full water pressure is then left applied to a bad regulator- after a while you will see the pressure spike high.

Hi PHXtech,

I have seen this here in Canada. When do you see the problem in Rinse/disinfection programs or in dialysis? If I were to guess it is in rinse programs. One question, do your machines have a dialysate sampling option. If Yes then this is your problem and V28 is stuck.

Otherwise I would like to know more details regarding your problem.

I have been running the machine in the back room with gauges attached, so far I have not seen any pressure spikes, I will continue to run it since it would only pop off the line very infrequently. I am really not sure what the sampling option is. It has the UF sample but was popping off on the drain side of the checkvalve. When the machine was pulled from the floor the last time it was at the end of the patient run before any rinse programs were started.

As Highly Pressured said, you won't see the tubing pop off while the machine is running. The tubing will try to pop off at night (the water from the wall is turned on).