Remeha E.02.48 Fault Code: Causes, Fixes & Repair Costs
What does the Remeha E.02.48 fault code mean?
The E.02.48 code is a full lockout on Remeha Ace-series boilers (Tzerra Ace, Avanta Ace, Quinta Ace and similar). To understand it, it helps to know how Remeha structures its fault codes: the letter prefix tells you the severity — A.xx.xx is a warning, H.xx.xx is a blocking fault, and E.xx.xx is a lockout, meaning the boiler has shut itself down completely and will not restart without intervention. The number group 02.48 identifies a Function Group Configuration Fault, specifically that the boiler's main control unit cannot find or communicate with the SCB (System Control Board) expansion PCB — an additional circuit board fitted to the boiler to handle extra functions such as zone control or extended heating circuits. Because the boiler cannot resolve this configuration mismatch, it locks out as a safety measure. This is the lockout-level equivalent of the same underlying fault that appears as A.02.48 (warning) or H.02.48 (blocking) at lower severity thresholds.
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 corroded wiring connectors between main PCB and SCB board Common
Boilers vibrate during normal operation, and over months or years this can work connector plugs loose on the wiring harness that links the main control board (CU-GH) to the SCB expansion PCB. A poor connection is enough to prevent the boards from communicating, triggering the lockout. This is the most frequently found cause when an engineer investigates this code.
- Lost or corrupted configuration after a power interruption Common
If the boiler loses power unexpectedly — a tripped fuse, a power cut, or work on the electrical supply — the stored configuration data that tells the main board an SCB is present can become corrupted or wiped. The boiler then restarts without recognising the expansion board and locks out on E.02.48. Re-running the auto-detection routine (a menu function accessible to engineers) usually resolves this without replacing any hardware.
- Failed SCB expansion PCB Sometimes
The SCB board itself may have failed electronically — due to age, a power surge, or component degradation. When the board is dead or producing no response, the main controller logs it as absent and locks out. Replacement of the SCB PCB is required in these cases.
- Faulty main control PCB (CU-GH) Rare
If the primary control board has failed or developed a fault on the communication circuit, it may be unable to detect or talk to the SCB even when everything else is intact. This is relatively uncommon but should be considered if wiring checks and SCB replacement do not resolve the fault.
How to fix it
- Check your gas supply is working DIY safe
Before assuming an electronics fault, confirm that other gas appliances in your home (hob, gas fire) are working normally. If there is no gas supply to the property, contact your gas supplier — this is not a boiler fault in that case.
- Check system pressure is within range DIY safe
Look at the pressure gauge on the boiler. For most Remeha Ace boilers, normal cold pressure is between 1.0 and 2.0 bar. If it has dropped below 1.0 bar, top it up via the filling loop. Note that E.02.48 is a configuration fault and low pressure alone will not cause it, but it is worth ruling out before calling an engineer.
- Attempt a boiler reset (once or twice only) DIY safe
Locate the reset button on your Remeha boiler — usually a flame symbol with a line through it, or a dedicated reset button on the display panel. Press and hold for the duration indicated in your user guide (typically 3–5 seconds). Wait for the boiler to attempt a restart. If the E.02.48 code returns immediately or after a short time, do not keep resetting — repeated resets will not fix an electronics or configuration fault and can mask useful diagnostic information for the engineer.
- Engineer to inspect all wiring harnesses and connector plugs Gas Safe engineer
A Gas Safe registered engineer should check the wiring loom between the main PCB (CU-GH) and the SCB expansion board, reseating any connectors that have worked loose and checking for corrosion, chafing, or broken pins. A multimeter can confirm whether signals are passing correctly. This step resolves a significant proportion of E.02.48 faults without the need for parts.
- Engineer to run the SCB auto-detection routine Gas Safe engineer
Remeha's own service documentation recommends running an auto-detection sequence when the SCB PCB is not found. This is accessed through the boiler's installer menu and re-establishes the configuration relationship between the main board and the expansion PCB. After running the routine, the engineer will reset the boiler and confirm the fault has cleared.
- Engineer to replace the SCB expansion PCB if required Gas Safe engineer
If wiring checks and auto-detection do not resolve the fault, the SCB board itself has most likely failed. The engineer will source and fit a compatible replacement SCB PCB, re-run the configuration routine, and test full boiler operation before leaving.
- Engineer to consider main PCB (CU-GH) replacement if fault persists Gas Safe engineer
In the uncommon scenario where a new SCB board and correct wiring still produce an E.02.48 lockout, the main control board may be at fault. The engineer should carry out further diagnostics to confirm this before committing to a main PCB replacement, as this is the costliest component involved.
- Contact a Gas Safe registered engineer Gas Safe engineer
If the fault has not cleared after a reset or two, book a Gas Safe registered engineer as soon as possible. E.02.48 is an electronics and configuration fault — there is nothing further a homeowner can safely or usefully do, and leaving a locked-out boiler undiagnosed risks prolonged loss of heating and hot water.
Parts you may need
- Remeha SCB expansion PCB (SCB-02 or compatible) · from £180
- Remeha main control board CU-GH · from £320
- Wiring harness / connector loom (internal) · from £45
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 £120–£380, depending on the underlying cause.
Frequently asked questions
Can I fix Remeha E.02.48 myself by just resetting the boiler?
You can try a reset once or twice — occasionally a one-off power interruption causes this code and a reset is enough to clear it. However, E.02.48 is a lockout related to internal electronics and board communication, so if it returns after resetting, a Gas Safe registered engineer is needed. Do not keep pressing reset repeatedly, as this will not address the underlying fault.
What is the difference between A.02.48, H.02.48, and E.02.48 on a Remeha boiler?
All three codes share the same fault identity — a Function Group Configuration Fault where the SCB expansion PCB is not found — but the letter tells you how severely the boiler has reacted. A.02.48 is a warning: the boiler logs the issue but keeps running. H.02.48 is a blocking fault: the boiler stops operating until the fault is cleared but does not require a manual reset. E.02.48 is a full lockout: the boiler shuts down completely and will only restart after the fault is resolved and a manual reset is performed. The repair approach for all three is the same; E.02.48 simply means the boiler is no longer providing any heating or hot water.
How much does it cost to fix E.02.48 on a Remeha Ace boiler?
Most people with this fault pay somewhere between £120 and £380 in total. If the fix is simply reseating a loose connector and running an auto-detection routine, you are likely looking at a single call-out plus labour — roughly £120–£200. If the SCB expansion PCB needs replacing, expect £250–£380 including parts and labour. In the less common situation where the main control board (CU-GH) is at fault, costs can rise to £400–£550 or more, though this is not the typical outcome.
My Remeha boiler is more than 10 years old and has come up with E.02.48 — is it worth repairing?
Remeha Ace-series boilers are generally well built and many run reliably for 12–15 years with regular servicing. If a wiring fix or SCB board replacement resolves the fault for £150–£380, repair usually makes sense unless the boiler has other ongoing issues. If the main PCB also needs replacing and the boiler has had several recent faults, it may be worth getting a replacement cost quote to compare — a Gas Safe engineer can help you weigh that up after diagnosis.