Living with an insulin pump can be a game-changer for diabetes management, offering freedom and precision that daily injections often can’t match. But technology isn’t perfect, and neither is the human body. If you use a Tandem t:slim X2 or Mobi pump, you’ve likely encountered the occasional hiccup with your infusion set—or even with the pump itself. Common infusion pump issues reported to the FDA include software problems, alarm errors (such as missed or false occlusion alarms), confusing or hard-to-use pump interfaces, and even mechanical defects like cracked pump casings or battery failures. Sometimes, warnings and error messages can be unclear or too frequent, leading users to ignore important alarms. At other times, design flaws (like hard-to-read screens or unclear setup instructions) may cause errors during setup or normal use.

And of course, the most hands-on challenges for pump users often come from the infusion set: stubborn occlusion alarms at 2 a.m., adhesive patches that won’t stick during a workout, or unexplained high blood sugars. Infusion set troubleshooting and awareness of both pump and user-related pitfalls are essential skills for every pumper. By understanding both the technology and the process, you’ll be better prepared to tackle issues quickly and safely.

This guide is here to help you navigate those tricky moments with confidence. We’ll cover the most common Tandem pump issues users face—from kinks to adhesive failures—and provide practical, stress-free solutions to get you back on track.

1. Dealing with Occlusion Alarms

Few things are more jarring than the loud beep of an occlusion alarm, especially when you’re trying to sleep or enjoy a meal. This alarm signals that insulin flow is blocked somewhere between your pump’s cartridge and your body. While annoying, it’s a critical safety feature designed to ensure you get the insulin you need.

However, not all occlusion alarms are triggered by actual blockages. According to the FDA, some users encounter “false alarms” caused by software glitches or errors in the pump’s programming, while others may not receive alarms when there really is a blockage—especially if the pump’s interface is confusing or not user-friendly. Issues like missed or overly frequent warnings, clunky screens, or unclear alarm messages can also cause confusion and delay a proper response.

That’s why it’s important to always take occlusion alarms seriously, but also be aware that technological errors—including software misreads and unclear alerts—are possible. If you notice repeated alarms that don’t seem to match what you observe with your site and tubing, report these events to your pump manufacturer and healthcare provider, as they could indicate a device issue that needs to be addressed.

Common Causes & Solutions

• Kinked Tubing: Before panicking, check your tubing. Is it caught in your waistband, twisted around your pump case, or pinched under a seatbelt? straightening the tubing often resolves the issue instantly.
• Bent Cannula: If the tubing looks fine, the blockage might be under your skin. A “kinked” or bent cannula happens when the soft tube bends upon insertion or hits muscle. This usually stops insulin delivery completely. If you suspect this, you must change your infusion set immediately.
• Pressure on the Site: sometimes, simply leaning on your infusion site while sitting or sleeping can compress the tissue enough to block flow. If the alarm clears after you stand up or shift positions, this was likely the culprit.

Pro Tip: If you get an occlusion alarm, don’t just clear it and ignore it. Check your blood sugar. If you are high and not coming down after a correction, assume the site has failed and change it out.

2. Preventing and Fixing Adhesive Issues

There is nothing quite as frustrating as prepping a new site, inserting the set perfectly, and then having it peel off a few hours later. Adhesive issues are among the most commonly reported problems with infusion sets—not just due to skin or weather conditions, but sometimes because of factors related to the pump itself. According to the FDA, confusing or inadequate user interface design can contribute to improper setup, missed cues about adhesive placement, or unclear maintenance steps that compromise adhesion. Environmental factors also play a role: excessive sweating, high humidity, or friction from clothing may weaken the adhesive, and improper storage or expired supplies can increase the risk. Keeping that adhesive patch secure is essential for reliable infusion set care.

Why It Happens

• Skin Oils and Moisture: Natural oils, lotions, or leftover adhesive remover can prevent the patch from bonding to your skin.
• Humidity and Sweat: Intense exercise or hot weather can weaken the adhesive bond.
• Friction: Placing a site right where your waistband sits or where clothing rubs can physically peel the edges up.

Practical Fixes

• Prep Like a Pro: always clean the site with an alcohol wipe and let it air dry completely before insertion. Do not blow on it to dry it faster, as this reintroduces germs.
• Use a Barrier: Products like Skin-Tac™ create a sticky surface on your skin that acts like double-sided tape, significantly boosting adhesion.
• Add Reinforcement: Consider using an over-patch or a transparent dressing (like Tegaderm or IV3000) over the infusion set tape to secure the edges. You can cut a hole in the center for the connector.

3. Resolving “No Delivery” or High Blood Sugars

Sometimes, you don’t get an alarm, but your blood sugar numbers tell a different story. Unexplained highs that don’t respond to boluses are a hallmark sign of infusion set failure—often called a “silent occlusion.” According to the FDA and clinical reports, these “no delivery” events can be caused by a range of issues: mechanical pump or tubing problems, improper setup, cracks in the pump case, misaligned or kinked tubing, clogged cannulas, air bubbles, or even insulin crystallization within the set due to improper storage or prolonged heat exposure. Less commonly, software or interface errors might result in under-infusion without a clear alert. In some cases, the insulin itself can become less effective if it has been exposed to extreme temperatures or has expired. Regardless of the underlying cause, any persistent high blood glucose that doesn’t respond to a correction should prompt quick troubleshooting of your site, pump, and insulin supplies.

What to Look For

• Air Bubbles: Inspect your tubing for large air bubbles. A bubble of air moving through the line means you are missing out on units of insulin. If you see a significant gap, disconnect the tubing from your body and prime the air out.
• Tunneling: This occurs when insulin flows back up along the outside of the cannula and wets the adhesive patch instead of absorbing into your body. If you smell insulin near your site or the tape feels damp, the set has failed.
• Scar Tissue: Inserting into an area with lipohypertrophy (lumpy or hardened tissue) prevents proper absorption. Always rotate to a fresh, healthy patch of skin.

Action Plan: If your blood sugar is high (e.g., over 250 mg/dL) and doesn’t drop after a correction bolus, do not keep treating it with the pump. Take a manual injection with a syringe or pen to get the insulin working immediately, then change your infusion set.

4. Managing Pain and Bleeding at the Site

Insertion shouldn’t cause lingering pain. While a brief pinch or mild discomfort is normal, ongoing pain or visible site bleeding suggest something isn’t right. According to the FDA and clinical experts, improper insertion techniques—such as inserting the cannula too deeply, at the wrong angle, or into a site with too little fatty tissue—can increase the risk of hitting muscle or nerves, causing pain or even bleeding. Selecting inappropriate sites (over scars, in areas with minimal fat, or spots subject to frequent movement or pressure) can also contribute to discomfort and trauma. Additionally, device malfunctions, such as bent or kinked cannulas, have been documented as culprits for both pain and poor infusion. Always ensure you’re following best practices for site selection and insertion, and don’t hesitate to remove and replace a set if pain is persistent or if bleeding occurs.

When to Worry

• Hitting a Muscle or Nerve: If you feel sharp, stinging pain that doesn’t go away after a few minutes, the cannula may be hitting muscle or sitting too close to a nerve. It’s best to remove it and try a new spot.
• Bleeding: A tiny drop of blood upon removal is normal. However, if you see blood filling the cannula tubing (a “backflow”), it can block insulin delivery. If the site is bleeding actively or looks bruised and purple, remove the set and apply pressure.

Prevention Strategies

• Try a Different Angle: If you are lean or muscular, a 90-degree set might be too deep. Consider switching to an angled set like the AutoSoft 30 or VariSoft, which allows for shallower insertion.
• Numbing Cream: For children or those sensitive to needle pain, applying a topical numbing cream 30 minutes before insertion (and wiping it off thoroughly) can help.

When to Call for Help

Most infusion set troubleshooting can be handled at home, but there are times when you should reach out to your healthcare provider or Tandem technical support:

• You are experiencing frequent, unexplained lows or highs.
• Your insertion sites are consistently red, warm, or oozing pus (signs of infection).
• You are running out of usable sites due to scar tissue.

Remember, you aren’t alone in this. Every pump user faces these challenges eventually. By staying calm, investigating the issue methodically, and keeping your supplies stocked, you can handle these bumps in the road and get back to living your life.