IBC
Short Cycling
Boiler frequently short cycles, turning on and off every few minutes during a call for heat.
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Safety Warning
This repair may involve working with high voltage components or water connections. Always unplug the appliance before removing any panels.
If you are not confident in your ability to perform this repair safely, we strongly recommend contacting a professional technician.
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Possible Causes
Oversized boiler relative to load, Incorrect minimum firing rate settings, Low water volume in system, Faulty temperature sensor placement
How to Fix / Troubleshooting
Safety: Do not change advanced parameters without referencing the IBC manual.
- Check thermostat differential: Increase thermostat differential or cycle rate if adjustable to reduce rapid calls.
- Review outdoor reset: Ensure the outdoor reset curve is enabled and properly set so the boiler can modulate instead of cycling.
- Increase system volume: If the system is very small, adding a buffer tank can reduce cycling (professional task).
Persistent short cycling should be evaluated by a technician who can adjust modulation parameters and confirm correct boiler sizing.
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Repair Difficulty
Hard
4/5
Required Part
Buffer Tank (if added)
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