Intergas Boiler Error Codes: Common Faults & Reset Procedures

Quick Answer: Intergas boilers display fault codes as a flashing LED sequence or numeric codes depending on model. The most common faults are E2 (low water pressure / lack of water), E5 (overheating / high limit thermostat), and E9 (fan fault / flue blockage). Most Intergas boilers can be reset by pressing and holding the reset button for 3 seconds; persistent faults require diagnosis before reset. Intergas boilers must be serviced and repaired by a Gas Safe registered engineer.

Summary

Intergas is a Dutch boiler manufacturer with a strong presence in the UK market, known for their compact HRE (High Efficiency) and Compact HRE combi range. Intergas boilers have a distinctive two-heat exchanger design (primary and secondary) and are noted for their reliability, but like all boilers they produce fault codes when problems are detected.

Intergas fault codes are displayed either as a flashing LED pattern (older models) or as numeric/alphanumeric codes on the digital display (HRE and Compact HRE). The code format and reset procedure varies slightly between model generations. This article covers the main Intergas combi models sold in the UK including the HRE 24, HRE 28, HRE 36, and Compact HRE range.

Key distinguishing features of Intergas diagnostics: the boiler uses a two-part error display (an error number and a sub-code that indicates the specific component or condition). Sub-codes are particularly useful for diagnosis. Always note both the main code and the sub-code when investigating a fault.

Always verify error codes against the specific model's installation and service manual — Intergas has released multiple model generations and code meanings can vary.

Key Facts

Intergas Error Code Table

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Error Code Description Common Cause First Checks Action
E0 Internal error / PCB fault Electronic fault on PCB Power cycle the boiler Gas Safe engineer — PCB may need replacement
E1 Flame not detected / ignition failure Gas supply issue, igniter fault, gas valve fault Check gas supply to other appliances; check pilot (if applicable) Gas Safe engineer — check gas valve, electrode, lead
E2 Lack of water / low pressure System pressure below threshold Check pressure gauge; repressurise to 1.0–1.5 bar via filling loop Repressurise; if persistent, check for system leak; Gas Safe for filling loop issues
E3 Overheating — high limit thermostat Blocked pump, air locked, dirty heat exchanger Check pump running; bleed radiators Gas Safe engineer — check pump, check heat exchanger
E4 Burner lockout — safety limit Multiple ignition failures Reset after short wait Gas Safe engineer if recurring — gas valve, combustion analysis
E5 Flue gas temperature too high / flue sensor fault Flue blockage, sensor fault, inadequate combustion Check flue terminal externally for obstruction Gas Safe engineer — flue inspection, sensor check
E6 Fan fault / no fan signal Fan not running, fan speed sensor fault, wiring Check wiring connections to fan Gas Safe engineer — fan replacement if failed
E7 Flame signal detected when no flame expected Gas valve leaking, PCB fault Do not reset repeatedly — gas valve may be passing gas Gas Safe engineer urgently — gas valve inspection required
E8 Water temperature sensor fault NTC sensor failure, wiring fault Check sensor connections Gas Safe engineer — NTC sensor replacement
E9 Return temperature too high / CH sensor fault Pump fault, sensor fault, high return temperature Check pump operation Gas Safe engineer — pump and sensor check
E10 Combustion/CO detection fault (models fitted with CO safety) CO in flue circuit, combustion fault Ventilate area; do not reset Gas Safe engineer — full combustion analysis required

Sub-Code Reference (HRE Digital Models)

Many Intergas HRE models display a two-part code (e.g. E2.01). The sub-code provides further diagnosis detail:

Main Code Sub-Code Specific Meaning
E2 .01 Low water pressure — system pressure below minimum
E2 .08 Flow temperature sensor (NTC) open circuit
E2 .09 Flow temperature sensor short circuit
E2 .10 Return temperature sensor fault
E3 .01 High limit thermostat operated — overheating detected
E3 .02 Differential pressure switch (flow switch) fault
E5 .01 Flue gas thermostat fault
E5 .02 Flue gas temperature too high
E6 .01 Fan not detected at startup
E6 .02 Fan overspeed detected

Detailed Guidance

E2 — Low Water Pressure (Most Common Fault)

The E2 fault (lack of water) is the most frequently seen Intergas fault in domestic properties. The boiler pressure gauge will typically show below 0.5 bar — the boiler will not fire if pressure drops below its safety threshold.

Step 1: Locate the filling loop (usually a flexible silver braided hose between two isolation valves under or behind the boiler). Some Intergas models have an internal filling link — check the installation manual.

Step 2: With the boiler cold, slowly open both filling loop valves until the pressure gauge reads 1.2–1.4 bar. Close both valves. Do not overpressurise (above 2.5 bar risks the PRV releasing).

Step 3: Press the reset button. The boiler should restart.

Step 4: If the boiler loses pressure again within days or weeks, there is a system leak — this requires a Gas Safe engineer to locate and fix. Common leak points: radiator valve glands, pump seals, air separator connections, and the filling loop itself.

Step 5: If the pressure gauge shows adequate pressure but the E2 fault persists, suspect a pressure sensor fault — requires Gas Safe engineer.

E1 — Ignition Failure

The E1 code indicates the boiler attempted to ignite but no flame was detected. Possible causes:

For a single E1 occurrence: reset the boiler and observe. One lockout after a power cut or gas interruption is normal. If E1 recurs after reset, call a Gas Safe engineer.

E6 — Fan Fault

The fan fault (E6) prevents the boiler firing because the air/flue circuit cannot be confirmed as operational. The boiler's pre-purge sequence requires the fan to reach speed before the gas valve opens.

Common causes: fan motor failure (bearings worn, capacitor failed), fan speed sensor fault, fan wiring loose. Debris (bird nest, insect nest) in the flue can cause the fan to work against resistance and overheat.

Diagnosis: listen for the fan at startup. In normal operation you should hear the fan spin up before ignition. No fan noise = fan not running. Unusual noise = possible obstruction or bearing failure. Call Gas Safe engineer.

Condensate Blockage (Winter)

Intergas condensing boilers produce acidic condensate water that drains through a polypropylene pipe to a drain. In cold weather, this pipe can freeze or the siphon trap within the boiler can block.

Symptom: the boiler shuts down (usually E5 or general lockout) in cold weather, especially overnight. The condensate discharge point (usually near the outside wall) may show ice.

Immediate remedy: pour warm (not boiling) water over the external condensate pipe to thaw the ice. Reset the boiler. As a longer-term solution, the condensate discharge point should be properly insulated or the pipe routed internally.

Frequently Asked Questions

How do I perform a full reset on an Intergas boiler?

Standard reset: press and hold the reset button for 3 seconds. For a hard reset (power cycle): switch off the boiler at the programmer or room stat, turn off power at the switched fused spur, wait 30 seconds, restore power. If a fault code returns immediately after power-on reset, the fault condition is still present and the boiler is performing a safety shut-down — do not continue resetting without diagnosis.

My Intergas boiler pressure keeps dropping — what should I do?

Call a Gas Safe engineer. Repeatedly repressurising a leaking system is not a safe long-term solution — the fresh water constantly introduced to a pressurised system increases oxygen content which causes internal corrosion. The leak must be found and fixed. Common locations: radiator valve packings, pump seal, PRV weeping to drain, expansion vessel diaphragm failed.

Can I service my Intergas boiler myself?

No. Servicing a gas boiler requires Gas Safe registration. The service includes a combustion analysis using calibrated instruments, which is not possible without specialist equipment. Owners can maintain system pressure, bleed radiators, and clean external controls, but all internal gas-side work requires a Gas Safe engineer.

The boiler fires but then cuts out after 10–15 seconds — what fault is this?

This pattern (fires, then shuts off after a short period) is often a flame-sensing issue — the ignition electrode and flame sense electrode are the same component on many boilers, and if the flame sense circuit is not detecting the burner flame reliably, the boiler cuts out for safety. This typically means a fouled electrode, poor earthing, or weak flame signal. Requires Gas Safe engineer — combustion check and electrode inspection.

Regulations & Standards