How to Fix / Troubleshooting

Safety: Turn off power before changing wiring; configuration changes can be done with power on via the user interface.

Verify sensors: Check that outdoor, flow, and return sensors display realistic temperatures. Replace any faulty sensors as needed.
Check pump operation: Ensure the circulation pump runs when frost protection should be active (low outdoor temperature). If not, test and replace the pump if necessary.
Review settings: In the IVT control menu, confirm that frost protection is enabled and configured according to the installation manual.
Update firmware: If recommended by IVT, have a technician update the control firmware to the latest version.

In cold climates, do not rely on a system with known frost protection faults; have it repaired promptly.

Furnace indicates frost protection / anti-freeze error; system may not protect against freezing

Possible Causes