Potterton E161 Fault Code: Causes, Fixes & Repair Costs
What does the Potterton E161 fault code mean?
The E161 code signals a fan fault on Potterton boilers, closely related to the E160 code which covers the same component. Your boiler's fan is responsible for drawing combustion air in and expelling harmful flue gases safely out through the flue. Before firing up, the boiler's PCB (printed circuit board) needs confirmation that the fan is spinning correctly. It gets this confirmation via an air pressure switch, which detects the change in internal air pressure that a working fan creates. If that signal never arrives — or arrives erratically — the boiler locks out and displays E161 to prevent potentially dangerous operation. In some cases the boiler may also briefly show related codes such as E131, E151, E152, or E133, because a fan problem can mimic flue or ignition faults; always have an engineer confirm the root cause.
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 worn fan motor Common
Over time the motor windings can burn out and the internal bearings wear down, causing the fan to spin slowly, intermittently, or not at all. This is the most frequent reason for E161 appearing and usually requires a full fan replacement.
- Loose or damaged wiring to the fan Common
Vibration and age can loosen the electrical connections between the fan, air pressure switch, and PCB. A broken or intermittent connection means the PCB never receives a reliable signal that the fan is running, triggering the lockout even if the fan motor itself is fine.
- Faulty air pressure switch (APS) Sometimes
The air pressure switch translates the fan's airflow into an electrical signal the PCB can read. If the switch membrane splits, the hose connecting it to the fan housing becomes blocked or disconnected, or the switch contacts stick, the PCB sees no fan activity and locks out.
- Blocked flue or air intake Sometimes
A partial or complete blockage at the flue terminal or air intake restricts airflow enough that the air pressure switch never reaches the correct threshold, even with a healthy fan. Bird nests, leaves, or ice in winter are typical culprits.
- PCB fault Rare
If the PCB itself is not supplying the correct voltage to the fan, or is misreading the returning signal, the fan may be perfectly healthy yet still trigger E161. PCB failure is less common but should be considered after other components have been ruled out.
How to fix it
- Listen to the boiler at start-up DIY safe
Stand near the boiler when you call for heat. A healthy fan produces a steady hum before ignition. If you hear nothing, a grinding noise, or the fan starts then stops, note this down — it is useful information for your engineer and helps confirm the fan motor or its wiring is the likely cause.
- Check the external flue terminal for obvious blockages DIY safe
Head outside and look at the flue outlet (usually on an external wall or the roof). Remove any visible debris such as leaves, a bird nest, or accumulated ice. Never poke tools into the flue pipe itself — a visual check is all that is needed here.
- Reset the boiler once or twice DIY safe
Press and hold the reset button (typically marked with a flame symbol or 'Reset') for around three seconds, then release. Allow the boiler a full minute to attempt start-up. Repeat once more if it locks out again. Do not reset more than two or three times in quick succession, as repeated failed ignition attempts can indicate a deeper fault.
- Check your gas supply is active DIY safe
Confirm that other gas appliances in your home — such as a gas hob — are working normally. If they are not, contact your gas supplier, as a broader supply issue may be contributing to the fault.
- Do not attempt to access internal components Gas Safe engineer
Removing the boiler casing to inspect or test the fan, wiring, air pressure switch, or PCB must only be carried out by a Gas Safe registered engineer. Working on these components without the correct registration is illegal and dangerous.
- Book a Gas Safe registered engineer to diagnose and repair Gas Safe engineer
An engineer will remove the casing safely, measure fan motor winding resistance with a multimeter, check wiring continuity, test the air pressure switch and its connecting hose, and assess the PCB. Depending on findings they will repair wiring, replace the fan, replace the air pressure switch, or address a PCB fault. Always ask to see the engineer's Gas Safe ID card before work begins.
Parts you may need
- Boiler fan / flue fan assembly (Potterton compatible) · from £120
- Air pressure switch (APS) · from £35
- Fan wiring harness / loom · from £25
- 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 £220–£380, depending on the underlying cause.
Frequently asked questions
Is E161 the same as E160 on a Potterton boiler?
They are very closely related — both point to a fan circuit fault. E160 tends to indicate the fan has failed to start or reach the correct speed, while E161 suggests the boiler detected a fan problem during or after start-up. In practice, the diagnosis and repair process is identical for both codes, and a Gas Safe engineer will approach them the same way.
Can I fix a Potterton E161 myself?
The only safe steps a homeowner can take are checking for an obvious flue blockage, resetting the boiler a couple of times, and making sure the gas supply is on. Everything beyond that — opening the casing, testing the fan, replacing components — must be done by a Gas Safe registered engineer. Attempting internal boiler repairs without Gas Safe registration is illegal in the UK and extremely hazardous.
How much does it cost to fix a Potterton E161 fault?
Most people with this fault pay between £220 and £380 all in, which typically covers the engineer's time and a replacement fan or air pressure switch. If the PCB turns out to be the cause, costs can rise to around £400–£500 depending on the board and the engineer's rate. If your boiler is over 12–15 years old and the repair quote is high, it is worth asking the engineer whether a new boiler would be more cost-effective in the long run.
Why does my Potterton boiler show E161 only in cold weather?
Cold weather is a common trigger because low temperatures can cause the condensate pipe to freeze (restricting the boiler in a different way) and can also affect the flue terminal — ice or frost may partially block the air intake, preventing the air pressure switch from reading the correct pressure. Check the external flue terminal for ice and, if your condensate pipe runs outside, check whether it has frozen. If thawing the condensate pipe and clearing any ice from the flue terminal does not clear the fault, call an engineer, as the fan or APS may have an underlying fault that cold weather is exposing.