Potterton E163 Fault Code: Causes, Fixes & Repair Costs
What does the Potterton E163 fault code mean?
The E163 fault code on a Potterton boiler indicates a problem with the Domestic Hot Water (DHW) NTC (Negative Temperature Coefficient) temperature sensor. The boiler's PCB has detected that the sensor is either reading temperatures incorrectly, has gone into short circuit, or has developed an open circuit — meaning the PCB can no longer get reliable temperature data from the hot water circuit. When this happens, the boiler will typically lock out as a safety measure and display E163 until the underlying fault is diagnosed and resolved.
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
- Faulty or Degraded DHW NTC Sensor Common
The most frequent cause of E163. NTC sensors gradually degrade over years of use, losing their ability to measure water temperature accurately. Eventually the sensor drifts so far out of range — or fails entirely — that the PCB triggers a lockout and logs E163. A Gas Safe engineer can test resistance across the sensor terminals to confirm this quickly.
- Damaged or Loose Wiring to the NTC Sensor Sometimes
The wiring harness and connector plugs linking the DHW NTC sensor to the PCB can suffer from vibration over time, leading to intermittent or broken connections. Corrosion or water ingress near connector blocks can also cause high resistance or open-circuit readings that mimic a dead sensor. An engineer will inspect the loom and connectors before condemning the sensor itself.
- Vibration-Induced Connection Failure Sometimes
A boiler that has been running noisily — due to pump wear, kettling, or air in the system — generates more vibration than normal. Over time this can shake connector plugs loose and accelerate wiring damage, which then triggers the E163 code. Addressing underlying noise issues during the same visit can prevent a recurrence.
- PCB Failure Rare
If the NTC sensor and all associated wiring test as healthy, attention turns to the PCB itself. A faulty PCB may misread or fail to process the sensor signal altogether, causing a false E163. Engineers use a multimeter to verify correct voltage supply and signal integrity at the board. PCB replacement is the most expensive outcome but is relatively uncommon for this code.
How to fix it
- Check your gas supply is on DIY safe
Before assuming a component fault, confirm that other gas appliances in your home — such as a hob or gas fire — are working normally. If there is no gas supply to the property, contact your gas supplier rather than a boiler engineer.
- Attempt a boiler reset (once or twice only) DIY safe
Locate the reset button on your Potterton boiler's control panel (usually a flame symbol or labelled 'Reset'). Hold it for a few seconds and allow the boiler to restart. If the E163 code returns within a short while, the underlying fault is still present and further resets will not clear it — stop resetting and move to the next step.
- Check system pressure DIY safe
Glance at the pressure gauge on the boiler. It should read between 1 and 1.5 bar when the system is cold. If it has dropped below 1 bar, top it up via the filling loop according to your boiler's user manual. Low pressure alone will not cause E163, but it is worth ruling out before calling an engineer.
- Have a Gas Safe engineer test the DHW NTC sensor Gas Safe engineer
An engineer will disconnect the NTC sensor and measure its resistance with a multimeter, comparing the reading against the manufacturer's expected values at a known temperature. A reading that is out of range — or open/short circuit — confirms the sensor needs replacing. This is not a homeowner task as it involves accessing internal boiler components.
- Have the engineer inspect sensor wiring and connector plugs Gas Safe engineer
If the sensor itself tests within tolerance, the engineer will trace the wiring loom back to the PCB, checking for corroded pins, loose connector plugs, or chafed cable insulation. Damaged sections will be repaired or the loom replaced as needed.
- Have the engineer test and — if necessary — replace the PCB Gas Safe engineer
Should the sensor and wiring both pass inspection, the engineer will check the PCB for correct supply voltage and signal processing. A confirmed PCB fault means the board needs to be replaced with the correct part for your specific Potterton model. Once the faulty component is replaced, the engineer will reset the boiler to clear the E163 code.
- Call a Gas Safe registered engineer if the fault persists or you have not already done so Gas Safe engineer
All of the diagnostic and repair work for E163 must be carried out by a Gas Safe registered engineer. You can verify an engineer's registration at gassaferegister.co.uk. Do not attempt to open the boiler casing or interfere with internal components yourself.
Parts you may need
- DHW NTC Temperature Sensor (Potterton compatible) · from £25
- Wiring Loom / Sensor Harness · from £40
- PCB (Potterton model-specific) · from £200
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–£300, depending on the underlying cause.
Frequently asked questions
Is the Potterton E163 fault code dangerous?
E163 is not considered a safety-critical fault in the same way as a gas leak or carbon monoxide warning. The boiler locks out as a precaution because it cannot reliably monitor hot water temperatures, but there is no immediate danger to your household. That said, you should still get it looked at promptly — a locked-out boiler means no heating or hot water, and leaving sensor faults unaddressed can sometimes mask developing problems elsewhere in the system.
Can I fix E163 myself by resetting the boiler?
Resetting the boiler is worth trying once or twice, but it will only clear the code if the fault was a temporary glitch rather than a genuine sensor failure. In most cases the E163 code returns almost immediately after a reset, because the PCB detects the same sensor problem again. The reset function is designed to restart the boiler after a fault has been repaired, not to substitute for a repair. You will need a Gas Safe engineer to diagnose and fix the root cause.
How much does it cost to fix a Potterton E163 fault?
For the most common repair — replacing the DHW NTC sensor — you can typically expect to pay somewhere in the region of £100 to £200 including parts and labour. If the wiring loom also needs attention, the cost may be towards the upper end of that range. In the less common scenario where the PCB needs replacing, the bill can rise to £350–£500 or more depending on your specific Potterton model, as the board itself is an expensive component. Most engineers will charge a call-out and diagnostic fee (often around £80–£100) which is usually counted towards the repair cost if you proceed.
How can I prevent the E163 fault from coming back?
The best preventative measure is an annual boiler service carried out by a Gas Safe engineer. During a service, the engineer checks sensor readings, inspects wiring connections, and identifies early signs of component wear before they cause a breakdown. Keeping your boiler serviced also maintains efficiency and can be a requirement to keep your boiler's warranty valid. If your boiler has been making unusual noises, getting that investigated promptly reduces the vibration-related wear that can loosen sensor connections over time.