A caution for anyone who uses iPhone Loop

I have never seen this before. I use my phone frequently but I am not married to it. Maybe this is common and you have experienced this, but this is the first time I have ever seen it!

It happened today when I was out in the sun…

And it was totally disabled! The only option I had on it was that I could dial 911.

The point being that a disabled phone for a short while is a minor nuisance. But when it means you can’t take insulin, it’s a much bigger deal.

So I just wanted to tell everyone - if you use Loop, keep your phone out of the sun!


Haven’t ever seen this message and with this message/warning, I’ll be keeping a more close eye on it when we’re outdoors!

Thanks, @Eric !


I’ve seen that one, particularly when having to put a phone in a waterproof bag…I’m wondering whether there are cases that can help cool a phone and reflect some of the heat. The glass and aluminum of phones seems like it can increase the heat a bit sometimes.


@Eric I have never seen that & I use to live in Arizona tmp in the 120s. Thanks @Eric


@Eric I see the same type of warnings on Android especially on hot days. Direct sunlight will heat a smartphone up very quickly. Fortunately , a few minutes in front of the car ac generally gets things right again.


Slightly different, but I’ve seen similar issue on Tandem pump. It also shuts down insulin. The key is keep it out of direct sun. Never had an issue when not in direct sun.


Right! :palm_tree: :person_facepalming:

I was thinking about this as my phone or pump has never stopped for high temp, and I live in Texas. My pump is probably never more than a few degrees above body temperature. The same is true for my phone which normally resides in a pocket.

Bicycling is another story. The phone is mounted on the top tube facing up. I suppose it is not in full sun much as I tend to shadow it. The other thing is that there is a nice air flow over the phone. You know that no matter which way the wind is blowing, when riding you always have a headwind. :smile:

I’ll leave y’all alone for a while. I have an appointment with my personal trainer in 15 minutes, I will be out in the Texas heat. :hot_face:


I forgot my phone the other day on a roof deck in the direct sun in Chicago and found it with this message – first time that’s ever happened. It took a good 20 minutes in our a/c hotel room to cool it back down to working order. Does this mean that insulin delivery will revert to some sort of set mode or it will completely power down? That’s definitely scary.


This could depend on what pump system you are using. I am using Omnipod Dash pods with loop 3.2.3 & I beleve it will revert to what you have set as your standard basal rate. Like it is in open loop. YDMMV


For Loop (on phones), it will just follow the preprogrammed basal rates. Whatever your basal program was set for, it will continue with those rates. It does NOT stop delivery. :+1:

I am not sure about Tandem though.


Tandem X2 doesn’t rely on a smartphone. The pump screen will show IOB alarms and can do bolusing. If the connection between the CGM and pump fails C-IQ is suspended and reverts to set basal rate.

MOBI is screenless I imagine as long as there is a connection to the CGM it will control basal without the phone. Manual quick preset bolusing can be done without the phone.

That’s a bridge too far for me. No MOBIs in my future.


Yes, but I was referring to the actual Tandem pump itself. If it overheats, what happens to it?

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From the user guide
If a Tandem Mobi system or t:slim X2 insulin pump detects an internal temperature that is too high, it will stop insulin delivery and sound an alarm. The alarm is designed to prevent the use of insulin that may not work properly. To resume insulin delivery, the pump must be removed from the source of the extreme temperature.
Fun in the Sun with a Tandem Insulin Pump.

Probably true for any pump that is more than a simple motor driven syringe.


I can confirm this is what the tandem pump does.:upside_down_face: