Remeha E.00.16 Fault Code: Causes, Fixes & Repair Costs
What does the Remeha E.00.16 fault code mean?
The E.00.16 fault code indicates that the boiler's domestic hot water (DHW) cylinder temperature sensor is either disconnected, has been removed, or is returning a reading that falls outside the expected range. Because the boiler relies on this signal to manage hot water production safely, it cannot continue normal operation and enters a lockout state until a valid sensor reading is restored. This fault is most commonly seen on Remeha commercial and semi-commercial appliances paired with a separate hot water cylinder, rather than standard domestic combi units.
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
- Loose or disconnected sensor wiring Common
The cable connecting the DHW cylinder sensor to the boiler PCB can work loose over time, particularly after servicing or if the cylinder has been disturbed. Even a partially dislodged connector at either end of the cable is enough to break the circuit and trigger this code.
- Failed or degraded DHW sensor Common
Temperature sensors have a finite lifespan. Over years of thermal cycling, the sensor element can deteriorate and eventually stop returning a valid resistance value, causing the boiler to interpret the circuit as open even though nothing is physically disconnected.
- Sensor dislodged from cylinder Sometimes
The DHW sensor is typically clipped or strapped to the hot water cylinder or an immersion pocket. If the clip has weakened or the sensor has been knocked during maintenance, it may have fallen away from its mounting point, breaking the thermal contact and causing erratic or no readings.
- Damaged sensor cable Sometimes
The wire running between the sensor and the boiler can be pinched, kinked, corroded, or chafed against a sharp edge — particularly in plant rooms where cables are routed near other equipment. Physical damage to the cable insulation can cause an open circuit or intermittent fault.
- PCB connection or PCB fault Rare
In less common cases, the fault lies at the PCB itself — either the terminal block accepting the sensor lead has corroded or the relevant input circuit on the board has failed. This is usually only confirmed after the sensor and its wiring have been ruled out.
How to fix it
- Check the sensor is physically in place on the cylinder DIY safe
Locate the DHW cylinder sensor — it is usually a small clip-on probe or pocket sensor attached to the side of the hot water cylinder or to the flow pipework, with a thin cable running back to the boiler. Confirm it has not fallen off its mounting. If it has come loose and you can see it is simply a matter of refitting the clip without touching any gas pipework or electrical terminals, you can reseat it carefully; otherwise leave this to an engineer.
- Perform a single boiler reset DIY safe
Once you have checked the sensor position, press the reset button on the boiler as described in your user manual. If the fault clears and the boiler runs normally, monitor it over the next few hours. If the E.00.16 code returns promptly, do not keep resetting — a recurring fault needs an engineer, not repeated resets.
- Inspect the sensor cable for visible damage DIY safe
Follow the sensor cable from the cylinder back to where it enters the boiler casing. Look for obvious signs of damage such as cuts, crush marks, heavy corrosion, or loose connectors at the cylinder end. Do not open the boiler casing or touch any internal wiring — note what you observe and report it to your engineer.
- Engineer to test sensor resistance with a multimeter Gas Safe engineer
A Gas Safe engineer will disconnect the sensor and measure its resistance at a known temperature using a multimeter. A correctly functioning NTC sensor has a predictable resistance-temperature relationship; a reading of infinity (open circuit) or zero confirms the sensor has failed and needs replacing.
- Engineer to inspect and test the wiring loom Gas Safe engineer
If the sensor tests correctly in isolation, the engineer will check continuity along the full cable run, inspect the PCB connector for corrosion or bent pins, and verify the terminal block is secure. A damaged section of cable is repaired or replaced as required.
- Engineer to replace the DHW sensor if faulty Gas Safe engineer
If the sensor has failed, the engineer will fit a compatible replacement, secure it correctly to the cylinder, reconnect the wiring, and clear the fault code. The boiler is then tested through a full hot water cycle to confirm normal operation.
- Engineer to investigate PCB if fault persists Gas Safe engineer
If a new sensor and confirmed good wiring still produce E.00.16, the fault lies with the PCB input circuit. The engineer will advise on repair or board replacement — a decision that also takes boiler age and overall condition into account.
- Call a Gas Safe registered engineer Gas Safe engineer
If the boiler remains in lockout after your visual checks and a single reset attempt, contact a Gas Safe registered engineer. All internal wiring work, sensor replacement, and PCB diagnosis must be carried out by a qualified professional. You can verify any engineer's registration at the Gas Safe Register website (gassaferegister.co.uk).
Parts you may need
- DHW cylinder temperature sensor (NTC) · from £25
- Sensor cable/wiring harness · from £35
- PCB connector/terminal block · from £20
- Remeha Quinta Ace PCB (if required) · from £280
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 £100–£280, depending on the underlying cause.
Frequently asked questions
Is E.00.16 dangerous — do I need to stop using the boiler immediately?
The boiler will have already shut itself down as a safety precaution, so it is not producing hot water while the fault is active. This is not a gas-leak or combustion emergency, but you should not repeatedly reset and attempt to run the boiler in a fault state. Leave it locked out and arrange for an engineer — continuing to force resets can mask the underlying problem and potentially cause further wear.
Can I fix E.00.16 myself, or do I always need an engineer?
The only checks a homeowner can safely carry out are confirming the sensor clip is still in place on the cylinder and attempting a single reset. All electrical testing, wiring work, and part replacement must be done by a Gas Safe registered engineer. Working inside the boiler casing without the right qualifications is both unsafe and, under UK law, a requirement that this work be carried out by a registered professional.
How much does it typically cost to repair E.00.16 in the UK?
For most people this is a straightforward sensor or wiring repair. Expect to pay roughly £100–£280 including the engineer's call-out, labour, and parts. The sensor itself is usually inexpensive (around £20–£30), so the majority of the bill is labour. If the fault has damaged or been caused by the PCB, costs rise significantly — a replacement Quinta Ace PCB can cost £250–£400 for the part alone, plus labour — but PCB failure is the least likely cause of this particular code.
Why does E.00.16 only appear on some Remeha models and not on combis?
This fault relates specifically to a separate DHW cylinder sensor — a component that only exists when the boiler is paired with an external hot water storage cylinder or calorifier. Standard domestic combi boilers heat water directly on demand and have no cylinder sensor, so this code does not apply to them. E.00.16 is most commonly encountered on Remeha Quinta Ace commercial and semi-commercial installations where a buffer or indirect cylinder is part of the system.
Will an annual boiler service help prevent E.00.16 from occurring?
Yes. During a service, an engineer will check sensor connections, inspect cables for wear, and clean terminals — catching a failing sensor or a loose connector before it causes a breakdown. Sensors tend to degrade gradually, and a routine service is often where early-stage deterioration is spotted and addressed cheaply, rather than waiting for a full lockout fault to appear.