| F.75 | Pump fault/lack of water | The UPM3 does not generate the expected pressure increase during the self-check; verify by forcing the pump test (P.0) and checking that it rotates and that the pressure sensor registers Δp. |
| F.23 | High differential temperature safety disconnection | A blocked pump or low flow rate causes an excessive difference between flow and return; check the pump's rotation/rpm and ΔT, and review circulation levels in diagnostics. |
| F.24 | Safety lockout due to excessively rapid temperature increase | Lack of circulation due to blocked/low-performance pump or air; check pump activation, flow-return ΔT, and correct bleeding/filling. |
| F.320 | The heating pump is blocked. | The circulator rotor is jammed and not delivering flow; check by listening for a humming sound without circulation, perform pump test (T.001) and release or replace. |
| F.321 | The pump electronics are faulty. | The electronics of the UPM3 do not respond to the command (PWM/230 V) nor report rpm; check power supply/communication and replace if there is no response. |
| F.322 | The heating pump is overheating. | The circulator's electronics detect overheating (e.g., due to blockage/air); check bleeding and charging, casing temperature, and continuous operation. |
| F.323 | The heating pump is running dry. | The UPM3 has operated without water (air/insufficient priming) and does not generate flow; check filling and bleed, and replace if it has run dry. |
| F.324 | The electrical connection of the pumps has been interrupted. | Pump wiring/connector interrupted or harness damaged; check continuity and supply voltage to the pump and repair the harness. |
| F.325 | The heating pump has a fault. | General fault of the UPM3 (blockage or defective electronics); check with pump test and, if it does not respond or does not deliver flow, replace it. |
| F.089 | The integrated heating pump is not suitable for the appliance model. | A non-approved UPM3 has been installed for that model and the electronics detect it; confirm by reference/diagnosis and install the correct ref. |