portable oxygen concentrator

Hi All
I hope you are doing well and not getting Corona.
I have an Invacare XPO2 portable oxygen concentrator
Mod. xpo100B, Ser # 11JF029132
I am getting a 3 & 4 light alarm and the machine shuts off. I am thinking that it is working but refuses to. There are no secondary code lights on so I assume it is a code 3000.
ERROR CODE Operating Alarm 3000
ALARM LEDs 3, 4
SUB-ALARM LED None
Operating Alarms: This alarm group centers on the sieve beds and the PSA process. These are alarms for which there is no corrective action available to either the patient or the provider. However, there are sub-codes that can be accessed to help the Invacare service and repair centers.
There is a 4 pin RS232 plug. I have isolated RX, TX & ground. When running, the other pin is 0 volts (35 ohms to ground. Logic low?) and 3.3 volts when off or flashing codes. I’m not sure how to get info.
Invacare XPO100 Service Manual
https://www.manualslib.com/manual/846360/Invacare-Xpo100.html
User manual https://www.manualslib.com/manual/78249/Invacare-Xpo100.html
The compressor works okay. It puffs pressure when you inhale.
The 2.5 Watt heaters all have 15v. & ground & 90 ohms.
21.5 on the hour meter.
New battery.
All repair companies but one refused to work on it. That one wanted $1000.00 minimum.
They say only the store that sold it can get it repaired. They are out of business.
I even tried varying the output voltage on what looks like an oxygen quality sensor.
I am hoping someone will have connections to tell me what a code 3000 means.
Otherwise, I may go “Steam punk” on it with an external compressor motor (that one is
15v. 3 phase) and an Arduino micro-controller for valves & heaters.

Is there a leak or has the sieve material (zeolite) been Contaminated?

Is someone actually wearing/using the concentrator? Some detect whether or not any draw (breadths) are pulled as it tries to push concentrated O2 out.

It has been charging & ready for use for years. It worked when tested occasionally but not when we needed it. We replaced the battery a few years ago and again now. The hoses are very good. They look like silicone.
It does puff pressure when wearing the cannula when you inhale. It only runs for about 30 seconds before shutting off with alarm lights 3 & 4.

The manual mentions two nitrogen adsorbers - presumably there must be a changeover valve system and some way of purging / resetting the material?

Could one of the valves have stuck from lack of use?
The manuals do not give any schematics, so how it actually functions is guesswork..

rjenkinsgb said:

Could one of the valves have stuck from lack of use?

Click to expand...

Good catch.
There are 3 valves. One does the puffs. I will look into that.