My first answer is to quote the home page : "Please consult your physician
for medical questions, and your Rav (Rabbi) for halachic (Jewish law)
decisions."

My second answer is to excerpt the third post on the Jewish Insulin Pumpers
group archive which was written by Rabbi Meisels (dated September 2003):

*******start excerpt*********
When I started pumping (apprx. four years ago) I asked my rav and I was told
that I should everything in the usual way. (snip)

Again, my rav told me that I can change batteries or cartridges or sets
whenever needed. L'maise I have a routine with changing batteries, so I
don't wait until it tells me the 'low battery alarm', so having to change on
shabbos is very rare for me. (snip)

********end excerpt*********

We have a list specifically related to pump questions; to join please go to
our main page at www.friendswithdiabetes.org and click on the Jewish Insulin
Pumpers link.

"Ah guten Shabbos !

Yehuda Y. Scheff, Supervising Special Auditor Investigator
NYS AG - MFCU
120 Broadway, 13th Floor
New York, NY 10271-0007
Tel: (212) 417-5658
Fax: (212) 417-5410
E-mail: yehuda.scheff@...
NYS AG WEBSITE www.oag.state.ny.us