Combustion control fault
The 77 error code on Immergas boilers indicates combustion control fault.
Immergas 77 means: combustion control fault. The usual causes are a current out of range is detected on the gas valve, if the block or the anomaly persists it is necessary to call an authorized company (for example the or immergas) it is possible to check this anomaly only in the list of errors in the "information" menu. A Gas Safe registered engineer should diagnose the root cause.
What Does 77 Mean
The 77 code is shown by the boiler’s control board when it detects combustion control fault. The boiler then stops instead of continuing to run in that condition: the code is the appliance reporting a problem, not proof that the boiler is broken.
| What you see on the boiler |
|---|
| The display shows 77 and the boiler stops until the fault is cleared |
Common Causes
Causes documented in the Immergas service literature published by centriassistenza.org, cross-checked against the manufacturer’s fault-code table.
| Cause |
|---|
| A current out of range is detected on the gas valve |
| If the block or the anomaly persists it is necessary to call an authorized company (for example the |
| Immergas) It is possible to check this anomaly only in the list of errors in the "Information" menu |
Safety Warning
77 is a gas-related fault. Never attempt to repair or adjust the gas valve, burner assembly, or flue system yourself. All gas work must be carried out by a Gas Safe registered engineer (UK) or licensed HVAC technician (US). Repeated resets after ignition failure can cause unburnt gas to accumulate inside the combustion chamber — this is a serious safety hazard. If you smell gas at any point, turn off the gas supply at the meter, open windows, leave the property, and call your gas emergency service immediately. Guasto legato al gas. Non aprire il rivestimento della caldaia e non tentare di riparare la valvola del gas, il bruciatore, il sistema di accensione o il condotto fumi. Ripristini ripetuti sono pericolosi. La diagnosi e la riparazione devono essere effettuate da tecnico qualificato.
Parts & Prices
Prices shown are indicative. Actual prices and availability vary by region.
How to Fix It
The boiler does not start
The appliance does not start
Refer to the Immergas service documentation for the detailed procedure. Only a qualified engineer should carry out these repairs.
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Affected Models
Immergas models that can display fault code 77:
| Model Family | Output Range | Frequency |
|---|---|---|
| All Immergas models | — | Possible |
Frequently Asked Questions
The boiler does not start. According to the technical documentation, this is the first check on the list for 77.
77 is classified as a high-severity fault: it involves gas, combustion or flue components. Do not keep resetting the boiler and do not attempt the repair yourself — call a Gas Safe registered engineer.