Remeha E.00.09 Fault Code: Causes, Fixes & Repair Costs
What does the Remeha E.00.09 fault code mean?
The E.00.09 code appears on newer Remeha commercial and semi-commercial models such as the Quinta Ace and Gas 310/610 series, where fault codes use the dotted E.00.XX format. On older domestic models like the Avanta Plus, the same underlying fault displays as E9 or E09. Depending on the specific model, E.00.09 signals either a water circulation problem — where the boiler cannot confirm adequate flow through the heat exchanger — or a flame/ignition failure, where the burner fails to establish or hold a stable flame. In both cases the boiler shuts down as a safety measure. Low system pressure, a faulty flow NTC thermistor, a seized or blocked circulation pump, or an ignition electrode issue are the most common root causes. The fault must be cleared before the boiler will restart.
General guidance only — not a substitute for professional advice, and not certified by a Gas Safe engineer. Always have your specific appliance assessed by a qualified professional. Any gas work must be carried out by a Gas Safe registered engineer. If you smell gas or suspect carbon monoxide, leave the property and call the National Gas Emergency line on 0800 111 999.
Common causes
- Low system water pressure Common
If the system pressure has dropped below the boiler's minimum threshold — typically under 0.8 bar — the boiler cannot confirm safe circulation and locks out. Pressure should sit between 1.0 and 1.5 bar when the system is cold. A gradual pressure drop usually points to a small leak somewhere in the system or pipework.
- Faulty flow NTC thermistor (temperature sensor) Common
The flow NTC measures the temperature of water leaving the heat exchanger. If the sensor drifts out of its expected resistance range, gives an implausible reading, or has damaged wiring or a loose connector, the boiler interprets this as a circulation or overheat condition and raises the fault. The NTC is one of the most frequently replaced components for this code.
- Circulation pump failure or blockage Sometimes
If the pump is seized, air-locked, or obstructed by sludge, water cannot move through the heat exchanger at the required flow rate. The boiler detects the resulting temperature rise or lack of flow confirmation and shuts down. Older systems with no magnetic filter are particularly prone to pump damage from debris.
- Ignition or flame failure (model-dependent) Sometimes
On models where E.00.09 relates to ignition rather than circulation, the burner either fails to light or the flame extinguishes shortly after starting. A dirty or worn ignition electrode, a contaminated flame sensor, or a low gas supply can all prevent the boiler from establishing a stable flame within the allowed ignition window.
- Wiring fault or PCB issue Rare
Damaged wiring to the flow NTC, pump, or ignition components — including corroded terminals, chafed cable, or a short circuit — can produce the same fault signals as a failed component. In rare cases the PCB itself develops a fault that causes incorrect sensor readings or failure to fire the ignition circuit.
How to fix it
- Check the system pressure gauge DIY safe
Look at the pressure gauge on the boiler front panel. It should read between 1.0 and 1.5 bar when the system is cold. If it reads below 1.0 bar, use the filling loop to top the system up to approximately 1.2–1.5 bar, then close the filling loop valves fully. If pressure drops again within a few days, there is a leak that needs a Gas Safe engineer to investigate.
- Reset the boiler once DIY safe
Once pressure is confirmed as correct, press the reset button on the boiler's control panel and wait at least 60 seconds for the boiler to attempt a restart. Observe whether it fires up normally or locks out again. Do not reset more than two or three times in total — repeated resets without success will not fix an underlying fault and can mask the problem.
- Check for obvious leaks around the boiler DIY safe
Visually inspect the pipework visible beneath and around the boiler for drips or damp patches, particularly around sensor pockets and pipe joints. Report any leaks you find to a Gas Safe engineer rather than attempting to fix them yourself.
- Engineer to test the flow NTC thermistor Gas Safe engineer
A Gas Safe engineer can remove the flow NTC and measure its resistance with a multimeter at a known water temperature. The reading is then compared against the manufacturer's resistance-temperature curve for that sensor. A reading outside the acceptable range confirms the sensor needs replacing.
- Engineer to inspect and test the circulation pump Gas Safe engineer
The engineer will check that the pump is receiving power, that its capacitor is functional, and that the impeller is not seized by debris. They may also check system water quality for sludge, and recommend a power flush or installation of a magnetic filter if the water is contaminated.
- Engineer to inspect ignition electrode and flame sensor Gas Safe engineer
If the fault is ignition-related on this particular model, the engineer will inspect the ignition electrode for wear or carbon deposits, clean or replace the flame sensor, and verify that the gas valve is opening correctly during the ignition sequence. Gas valve work must only ever be carried out by a Gas Safe registered engineer.
- Engineer to inspect wiring and, if necessary, the PCB Gas Safe engineer
If all components test as functional, the engineer will trace the wiring harness for damage or corrosion and check connector pins on the PCB. PCB replacement is a last resort given the cost involved, and a reputable engineer will exhaust all other diagnoses first.
- Call a Gas Safe registered engineer if the fault persists after basic checks Gas Safe engineer
If topping up pressure and a single reset do not clear the fault, the boiler requires hands-on diagnosis by a Gas Safe registered engineer. Do not continue attempting resets. Contact a Gas Safe engineer and have your boiler model number and any displayed sub-code ready — for example whether the display shows E.00.09 or a variation such as E9 — as this helps the engineer prepare the correct parts.
Parts you may need
- Flow NTC thermistor (temperature sensor) · from £30
- Circulation pump (compatible replacement) · from £120
- Ignition electrode · from £25
- Flame sensor / ionisation probe · from £20
- PCB (printed circuit board) · from £220
The exact spare depends on your boiler's GC number (on the data badge). Check this against the part before buying.
Typical repair cost
Expect to pay roughly £150–£380, depending on the underlying cause.
Frequently asked questions
What is the difference between E.00.09 and E9 on a Remeha boiler?
They refer to the same underlying fault type but appear on different model generations. The E.00.09 format is used on newer Remeha commercial and semi-commercial boilers such as the Quinta Ace and Gas 310/610 series, which use a dotted numeric display system. Older domestic models like the Avanta Plus show the same fault category as the simpler code E9 or E09. The root causes — low pressure, a faulty NTC sensor, pump issues, or ignition failure — are consistent across both formats, although the exact diagnostic steps may differ slightly by model. Always cross-reference with your specific model's documentation or call Remeha's technical helpline if you are unsure.
Can I fix Remeha E.00.09 myself?
There are two checks a homeowner can safely carry out: verifying the system pressure is between 1.0 and 1.5 bar (and topping up via the filling loop if it is low), and pressing the reset button once or twice. Beyond that, the fault involves either a faulty temperature sensor, a failing pump, or ignition components — all of which require hands-on testing by a Gas Safe registered engineer. Attempting to remove sensors, access the gas valve, or interfere with wiring without the correct training and registration is unsafe and potentially illegal.
How much does it cost to fix Remeha E.00.09 in the UK?
For the most common repair — replacing the flow NTC thermistor — expect to pay roughly £150 to £220 including parts and labour. A circulation pump replacement typically costs £200 to £380 all-in. An ignition electrode or flame sensor is usually inexpensive in parts (under £30) so the cost is mainly the engineer's call-out and labour, typically £130 to £200 total. PCB replacement is less common but significantly more expensive — parts alone can reach £200 to £400 on commercial models — so if an engineer suspects the PCB early in the diagnosis it is worth getting a second opinion.
Why does my Remeha boiler keep losing pressure and showing E.00.09?
If pressure is dropping repeatedly — for example every few days or weeks — there is almost certainly a leak somewhere in the system, either at a radiator valve, a pipe joint, or internally within the boiler itself. A one-off pressure drop can occasionally be caused by air escaping the system after bleeding radiators, but recurring drops need a Gas Safe engineer to trace and repair the leak. Continuously topping up without finding the source will not fix the fault and could mask a more serious issue such as a weeping heat exchanger.