Introduction; question on Medtronic 'A21' pump error on startup

[Eric Jensen]

Hi all,

I've just joined the group, so I thought I'd introduce myself and ask my first question.  I've been T1D for 21 years, and on a pump + CGM for about 10 years.  My day job is astronomy - teaching at the college level, and doing astronomy research.  So I do a lot of coding for my research, and a bit of work with hardware in our observatory.  I'm very excited about building my setup and eventually getting up and running with a closed loop, though I still have some reading and work to do before I get to that point.  Kudos to all of the people who have made this possible.  

First question, which I didn't see covered anywhere in the docs or in this forum.  The Medtronic pump I'm going to use for looping has been sitting in a drawer without a battery for 18 months (I switched to a Tandem then).  When I put a battery in it to start up, it gave error 'A21'.   Have other people seen this alarm, or know what it means?  I can't find a listing of alarm codes online. 

A thread here:  http://forums.childrenwithdiabetes.com/showthread.php?70277-Medtronic-cgm-a21-error

suggests that it could indicate that the internal battery that holds the settings while you change batteries is getting low, but there was no documentation to back that up.   I don't know whether it's true that the pump actually uses a battery for this, or if it charges some sort of capacitor to hold settings across a battery change.  So an empirical question is just whether people using older Medtronic pumps have any problems losing settings when changing batteries. 

The pump otherwise seems to start up fine once I clear the alarm, though I haven't filled it yet. 

Thanks for any information.  

Eric

[Scott Leibrand]

I'm not quite sure of this, but I think that just means "you left the battery out for too long, and we lost all your previous settings".  IIRC you just have to set it up again from scratch like a new pump. 

-Scott

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[Justin Mangino]

I can not add much to Scott, however When googling it mostly points to the battery left out. Some sources state that the battery connector cover is faulty and needs a replacement, however I would replace the battery and take a look into the error history. My girlfriend and I are in the process of purchasing a 522 with this very same error code.

[Eric Jensen]

I can verify now that when I took the battery out for a bit (~24 hours), and then reinserted and restarted the pump, I did *not* get the error code a second time.   So my guess is that Scott is right - the pump can hold onto settings for a while, but eventually loses them, and gives this error on the next start.   If true, this would mean that the code doesn't indicate a long-term problem, which would be great. 

[Justin Mangino]

That's good news thank you for testing this as well! 

[Anh Nguyen-Klingner]

Hi,

I have a 723, and when I insert the battery, there is an alarm with error code A21.  

Did anyone confirm the A21 error code?  A pump just arrived for us and there is this error.  

If you are able to clear by just remove the battery for ~24 hours, will you please confirm?

Best,

Anh

[Anh Nguyen-Klingner]

Hi Eric,

I just bought a pump and the long wait is over, it arrived.  When a battery is inserted, I encountered the same error code you mentioned, A21.  

Did you ever find out what to do the clear this error?  Will it impact the performance of the pump?

Best,

Anh

[Robert Steed]

An A21 typically means there is a problem with the electrical supply.  It could be substandard batteries (I believe Medtronic specifies a specific Energizer cell, but I've used other brands).  I've also seen it when the contacts are oxidized - this includes on the batteries, the battery contacts in the pump (both in the cap and the contact deep in the case), and the contacts where the cap meets the body of the pump.  Gently polishing these (a pencil erase does well) may help.

[Iain Cartwright]

My 722 produces the A21 error every time I change the battery. Only started when I started using Lithium batteries but happens everytime now. The rewind is a pain and the the clock needing resetting but no loss of settings.