System side flow sensor fault
The 48 error code on Immergas boilers indicates system side flow sensor fault.
Immergas 48 means: system side flow sensor fault. The usual causes are this occurs if the ntc sensor sent to the system side does not work correctly, if the block or the anomaly persists it is necessary to call an authorized company (for example the or immergas). error codes beyond 31 are not displayed on the carv2e. You can safely reset the boiler once — if 48 returns, do not keep resetting. A qualified heating engineer should diagnose the root cause.
What Does 48 Mean
The 48 code is shown by the boiler’s control board when it detects system side flow sensor 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 48 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 |
|---|
| This occurs if the NTC sensor sent to the system side does not work correctly |
| If the block or the anomaly persists it is necessary to call an authorized company (for example the |
| Immergas). Error codes beyond 31 are not displayed on the CARV2e |
| Super CAR display |
| The board detects an anomaly on the system flow sensor (Optional) |
Safety Warning
48 involves electrical or pressure-related components. Do not attempt repairs without proper qualifications. Ensure the boiler is electrically isolated before any inspection. If you notice water leaks, unusual sounds, or pressure anomalies, contact a qualified heating engineer immediately.
Parts & Prices
Prices shown are indicative. Actual prices and availability vary by region.
How to Fix It
The boiler continues to operate
The appliance operates with possible fluctuations in the system temperature
The boiler operates with possible oscillations in the system temperature
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 48:
| Model Family | Output Range | Frequency |
|---|---|---|
| All Immergas models | — | Possible |
Frequently Asked Questions
The boiler continues to operate. According to the technical documentation, this is the first check on the list for 48.
48 is not classified as a high-severity fault, so the boiler can be reset once. If 48 comes back, stop resetting: the underlying cause is still there and needs a qualified heating engineer.