One of the best things about peristaltic pumps is how tough and reliable they are. They’ll move abrasive slurry, thick chemicals, even fluids with gas bubbles—without blinking. But if you’re noticing a drop in flow rate, something’s off.
Here’s a practical rundown of why your peristaltic pump might be losing flow—and what you can do to fix it.
1. Worn or Deformed Hose
This is the number one culprit. The hose or tube inside the pump takes a beating with every rotation. Over time, it fatigues, becomes less elastic, and stops fully rebounding after the rollers pass.
What to look for:
- Flattened hose
- Visible cracking or delamination
- Flow rate is lower at the same RPM compared to when new
Fix:
- Replace the hose or tube (don’t wait for it to fail)
- Stick to the recommended replacement schedule from the manufacturer
- If wear is rapid, double-check hose material compatibility with your fluid
2. Incorrect Roller (or Shoe) Pressure
Some pumps allow you to adjust the compression force on the hose. If the rollers or shoes aren’t compressing firmly enough, fluid won’t be fully displaced. If it’s too tight, you’ll wear the hose prematurely.
Fix:
- Recalibrate roller pressure to spec
- Ensure even pressure across the entire contact zone
- If the pump has an adjustable shoe, double-check the setting post-hose replacement
3. Reduced RPM or Control Signal Issues
If your pump is running on a VFD or controlled via PLC, any hiccup in the control system can result in lower speed—and lower flow.
What to check:
- Actual RPM vs setpoint
- Changes in speed signal from a flow controller or SCADA system
- Motor drive alarms or fault history
Fix:
- Confirm signal scaling and setpoints in your control system
- Run the pump manually to see if full speed restores normal flow
- Rule out power supply or motor issues
4. Suction Side Restrictions
Peristaltic pumps are great at self-priming and handling lift—but they still need an unrestricted path on the suction side. If there’s a blockage, collapsed hose, or partially closed valve, your flow will suffer.
What to look for:
- Collapsed or kinked suction hose
- Clogged strainer or check valve
- Unusually high suction vacuum readings
Fix:
- Clean or replace filters and strainers
- Check hose condition, especially if it’s soft-walled or worn
- Make sure your fluid supply tank isn’t running empty
5. Hose Material and Fluid Compatibility
Some fluids cause hoses to swell, harden, or degrade over time. That changes how the hose responds to compression—and ultimately reduces flow.
Fix:
- Review chemical compatibility charts for your specific hose material
- Consider switching to a different formulation (e.g., Norprene, Viton, Tygon, etc.)
- Monitor hose dimensions and elasticity during regular maintenance
6. Pressure Buildup on the Discharge Side
Peristaltic pumps can only handle so much backpressure. If your system pressure increases due to a fouled filter, closed valve, or long discharge line, flow rate will drop.
What to check:
- Pressure gauge on the discharge side
- Valve positions and inline restrictions
- Recent changes to downstream piping
Fix:
- Open throttled or closed valves
- Clean downstream filters or flow meters
- Reduce line length or elevation where possible
Final Thoughts
Peristaltic pumps are incredibly forgiving—but they’re not immune to wear, blockage, or system changes. If you’re seeing a drop in flow, go through the basics: check the hose, confirm speed, inspect suction and discharge paths, and don’t ignore system pressure.
Most of the time, it’s not a catastrophic failure—it’s a maintenance tweak, control setting, or simple hose replacement.
Still stuck? Reach out. We troubleshoot these pumps all the time, and we’re happy to help you get it flowing again.
