Saunier Duval Fault Codes

Select a fault code to see its meaning, common causes and how to fix it.

F.00 The F.00 fault code (sometimes displayed as F0) appears on Saunier Duval boilers when the control board loses its… Read more →
F.01 The F.01 fault code (also shown as F1 or error 01 on some displays) indicates that the boiler has failed to establish a… Read more →
F.02 The F.02 code (sometimes displayed as F2) signals that your Saunier Duval boiler has detected a problem with its… Read more →
F.03 The F.03 code on Saunier Duval boilers has two distinct meanings depending on which model series you own. On older… Read more →
F.20 The F.20 code appears on most Saunier Duval boilers — including the Themaplus Condens, Thema Condens, Isomax, and… Read more →
F.24 The F.24 code indicates that your Saunier Duval boiler has detected little or no water flowing through the central… Read more →
F.26 The F.26 fault code on a Saunier Duval boiler signals one of two distinct problems depending on your model. On most… Read more →
F.27 The F.27 fault code on Saunier Duval Condens boilers signals one of two closely related problems, depending on the… Read more →
F.32 The F.32 fault code indicates that your Saunier Duval boiler has detected a problem with the combustion fan or flue gas… Read more →
F.33 The F.33 fault code on Saunier Duval boilers has two distinct meanings depending on the model. On most condensing combi… Read more →
F.42 The F.42 code (sometimes displayed as F42, with the decimal point appearing between flashing digits on the display)… Read more →
F.49 The F.49 code indicates that the boiler has detected a problem on its eBUS — the internal digital communication network… Read more →
F.52 The F.52 code points to a problem with the central heating NTC (Negative Temperature Coefficient) temperature sensor —… Read more →
F.53 The F.53 code appears when your Saunier Duval boiler attempts to light but cannot establish a stable flame during the… Read more →
F.54 The F.54 code tells you that your Saunier Duval boiler has detected an insufficient gas supply — either no gas is… Read more →
F.56 The F.56 code appears on Saunier Duval condensing boilers when the control board detects an abnormally rapid rise in… Read more →
F.57 The F.57 code indicates that your Saunier Duval boiler has detected a serious underlying fault and has automatically… Read more →
F.61 The F.61 fault code signals that the boiler's PCB (printed circuit board) has detected a problem controlling or… Read more →
F.62 The F.62 code appears when your Saunier Duval boiler detects that the gas valve has not closed correctly. Rather than… Read more →
F.63 The F.63 fault code points to an electronic failure within the boiler's main printed circuit board (PCB), specifically… Read more →
F.64 The F.64 code appears when your Saunier Duval boiler detects a problem with its NTC temperature sensors or the… Read more →
F.65 The F.65 code indicates that the temperature of the boiler's electronic components — primarily the PCB (Printed Circuit… Read more →
F.67 The F.67 fault code appears on Saunier Duval boilers when the main PCB (printed circuit board) is not receiving a valid… Read more →
F.68 The F.68 fault code appears when the boiler's PCB detects that the flame signal is erratic, too weak, or otherwise… Read more →
F.70 The F.70 code points to an electronic identity or configuration problem with the boiler's main circuit board (PCB).… Read more →
F.71 The F.71 code appears when your Saunier Duval boiler detects that the flow temperature sensor (NTC) is reporting a… Read more →
F.72 The F.72 code appears when your Saunier Duval boiler detects a persistent and excessive difference between the water… Read more →
F.73 The F.73 code appears when the boiler's water pressure sensor sends a signal that falls outside the expected range, or… Read more →
F.74 The F.74 code tells you the boiler's PCB is receiving a signal from the water pressure sensor that is outside the… Read more →
F.77 The F.77 fault code on a Saunier Duval boiler signals that the boiler's control system has detected a problem with… Read more →
F.79 The F.79 fault code on Saunier Duval boilers indicates that the control board cannot obtain a valid temperature reading… Read more →
F.81 The F.81 code indicates that the boiler has detected an abnormal overheating event on the domestic hot water (DHW)… Read more →
F.83 The F.83 code appears when the boiler's control board detects an abnormal difference between the flow and return water… Read more →
F.84 The F.84 fault code indicates that the Saunier Duval boiler's control board has detected a sustained or implausible… Read more →
F.85 The F.85 code indicates that the boiler's PCB has detected a persistent, abnormal temperature difference between the… Read more →
F.86 The F.86 code appears on Saunier Duval boilers when the boiler's dedicated FLOOR safety input detects a problem with… Read more →
F10 The F10 code indicates that the boiler's central heating return thermistor (NTC sensor) has developed a fault. This… Read more →
F11 The F11 fault code on Saunier Duval boilers covers two distinct scenarios depending on your model. On most Condens,… Read more →
F12 The F12 code on a Saunier Duval boiler signals a breakdown in electronic communication within the boiler's control… Read more →
F13 The F13 fault code on a Saunier Duval boiler points to a problem with the main control board (PCB). The boiler's… Read more →
F22 The F22 code appears when your Saunier Duval boiler detects that the water pressure in the heating circuit has dropped… Read more →
F23 The F23 code appears when your Saunier Duval boiler detects that the temperature difference between the flow pipe… Read more →
F28 The F28 code means your Saunier Duval boiler has tried to light the burner three times in a row and failed every time.… Read more →
F29 The F29 code indicates that the boiler's burner successfully ignited but the flame then went out unexpectedly during… Read more →