What does 24v low mean and what board would cause this failure?

When addressing equipment issues, it is good to add manufacture and model. However, this error is a commen Fresenius code. The most commen failure is the Acuator board, don't forget to swap-out the EPROM from the old board. On the subject of board replacement, there is a company called H&S Technical (800)923-2486, that has most manufacture boards (on exchange) for half the manufacture cost, if not more.

Good luck with all your endeavors

When do you get the message? If it is during machine start-up the machine is performing a "POST" (power on self test)If it does not pass this test a fatal watchdog alarm happens which usually generates a 24V low alarm. If it does not see 24V, RL1 on the power control brd. cannot energize therefore it will fail the test. If you look at a schematic showing the entire electronic distribution, you will see that its looking for monitoring the 24v to the display, all modules and boards. Hope this helps.

Thanks for the help, I just reseated all the boards and this cleared the alarm. and yes it was on start up.

i have found that with my new k machines will give this alarm if you lose power due to a building power failure than a power surge when you get power again. when the machine powers up again this alarm can occur. to trick the machine into clearing the alarm and retaining all the patient info. pull out the power cord when the alarm comes up and then after replacing it, the machine thinks it's it's just a interruption of power not a power surge. i hope this makes sense.