Need some help with two seperate 2008H each with approximately 30K hours.

Problem 1: Recir error in heat disinfect, have tried obvious (pump pressures, valve 39, rebuilt pressure reg's) to no avail. Machine will reach 80c+ start counting down then go into recirc error

Problem 2: Fail negative stabilization test, again have tried obvious stuff, this one there is air present at flow/bypass valve but it does not seem to be coming from b/c. Have replaced all orings on valves on b/c, flow/bypass valves mounting block, even tried different condo cell thermistor, still fails.

Any help or suggestions would be greatly appreciated. Remember these are two different machines not one with two problems.

Stumped,

Problem #1: Try swapping out the blancing chamber from another machine. If it works, check for a leaky valve or bad membranes.

Problem #2: A couple of years ago I had this same problem. After working on it for 2 weeks I called in the Fresenius field tech. After 3 days, he finally found that it was the o-ring in the deairation oriface in the hydroblock.

Good luck!

The flow recirc error is caused by a bad de-aeration pump head. Even though you can probably get it to -24 in vacuum, when it is in heat disinfect, valve 39 opens and there isn't any neg pressure and you get the error. I had the exact same prob. Let me know how it works out by posting a reply here.

It is also my recommendation to replace the Deairation Pumphead. I've had the same experience on several different occasions. I was able to obtain a proper pressure reading of -24mmhg in dialysis mode but received a recirc error whenever in Heat Disenfect.
Good Luck!!

tried pump head but didn't work

Problem 1
Sounds like a monitoring problem. I would check your P-Dial #9.
The problem you are having is very hard to troubleshoot.

You realize this post is 7 years old?