Potterton Boiler Fault Codes: The Complete Guide

How Potterton Fault Codes Work

Modern Potterton boilers run a constant internal check on pressure, water flow, ignition, and airflow. The moment one of those checks fails, the boiler locks itself out and shows a code on the display. This isn't a fault with the display — it's the safety system doing exactly what it's designed to do, stopping the boiler before a small problem turns into a bigger one, like a cracked heat exchanger or a burst pipe.

That lockout behaviour is consistent across the Potterton range, including the Promax, Gold and Performa combi and system models. What changes is the number that follows the E, and that's the bit that actually tells you what's wrong.

Potterton Fault Codes at a Glance

Here are the codes that come up most often on Potterton boilers:

• E1 / E119 — low system water pressure
• E133 — frozen condensate pipe, boiler in lockout
• E168 — general lockout, often power supply or PCB related
• E125 — poor water circulation or a blocked/faulty pump
• E160 — fan fault or blocked flue
• E110 — overheating, usually a blocked heat exchanger
• E28/E29 — no ignition or flame not detected
• E193 — control board and thermostat not communicating

We've covered the four most-searched of these in full guides below. If your code isn't on this list, our Potterton boiler faults page runs through the wider range.

E1 Fault: Low Water Pressure

The E1 code is the one we get asked about most, and it's usually the easiest to fix yourself. It means the pressure in your sealed heating system has dropped below the safe minimum — normally under 1 bar — so the boiler shuts down rather than run dry.

A drop in pressure on its own isn't a big worry. Systems lose a small amount over time through radiator bleeding, tiny weeps at joints, or normal wear. The fix is usually repressurising through the filling loop until the gauge reads within the range recommended for your model — commonly between 1 and 1.5 bar, though this varies. If the pressure keeps dropping back down within a day or two, that points to a leak somewhere in the system, and that's when it's worth getting an engineer to trace it rather than keep topping up.

Our full guide walks through locating the filling loop, opening the valves in the right order, and getting the pressure back in range safely: how to fix E1 fault on a Potterton boiler.

E133 Fault: Frozen Condensate Pipe

The E133 code is the classic winter fault. It means the plastic condensate pipe — the one that carries acidic waste water from the boiler out to an external drain — has frozen solid and can't drain. The boiler detects the blockage and locks out to stop water building up inside the system.

This shows up most on pipes that run externally, sit close to an outside wall, or have little to no insulation. It's almost always tied to a cold snap, and it's genuinely one of the few boiler faults a homeowner can safely thaw out without calling anyone. Locate the pipe, warm it gently along its length with lukewarm water or a wrapped hot water bottle — never boiling water, as it can crack the pipe — and once it's draining freely, reset the boiler.

If you can't find the pipe, it's cracked from the freeze, or the fault comes straight back after resetting, that's the point to stop and call a Gas Safe engineer rather than keep trying. Full steps, including how to spot the signs of freezing before it locks the boiler out, are here: Potterton boiler E133 fault code.

E168 Fault: Lockout, Power Supply or PCB

The E168 code is more of a catch-all than the others. It shows up when the boiler's control system has hit a problem it can't self-resolve — most often an interrupted or irregular mains supply, but it can also point to a fault with one of the internal electrical components or the printed circuit board (PCB) itself.

Because E168 covers a few different underlying causes, it's harder to diagnose from the display alone than E1 or E133. A recent power cut or a flickering supply is worth checking first, since a simple reset often clears it once power is stable. If the code returns straight after resetting, or your boiler has been fine on power but still won't clear the fault, that's a sign the issue sits with a component inside the casing, and that's not something to open up yourself.

Our guide covers what to check before you call someone, and what an engineer will typically test once they're on site: E168 Potterton boiler fault.

Other Potterton Boiler Faults

E1, E133 and E168 cover a large share of the call-outs we get, but they're not the whole picture. Codes like E125 (poor circulation), E160 (fan fault), E110 (overheating), and E28/E29 (ignition failure) all point to different mechanical or electrical issues, and most of them need a Gas Safe engineer to open the casing and test the actual component rather than something you can fix from the outside.

If your boiler is showing a code that isn't E1, E133, or E168, our Potterton boiler faults page breaks down the rest of the range, what each one means, and which ones are safe to attempt yourself versus which ones need an engineer straight away.

Potterton Fault Codes and Landlord Responsibilities

If you're a landlord rather than the person living in the property, a Potterton fault code is more than an inconvenience — it comes with a compliance obligation attached. Under the Homes (Fitness for Human Habitation) Act and standard tenancy obligations, a broken boiler counts as loss of heating and hot water, and tenants are entitled to have it fixed within a reasonable timeframe.

A few things worth building into how you handle a tenant reporting a fault code:

• Ask for the code, not just “the boiler's broken.” A tenant reading you the E1, E133 or E168 code off the display tells your engineer roughly what they're walking into before they've left the office, which speeds up the fix.
• Don't assume it's a DIY job because the tenant could reset it. A fault that clears with a reset but keeps coming back is still a fault. Repeated call-outs for the same code usually mean the underlying issue was never fixed, just masked.
• Keep your Gas Safety Certificate current. Landlords must arrange an annual gas safety check for gas appliances and flues they provide. Regular servicing and maintenance also help reduce the risk of faults appearing, since most of them trace back to something a check or service would have caught early.
• Use a reactive maintenance provider that can turn a call-out around fast. Winter fault codes like E133 spike hard the moment temperatures drop, and tenants without heating during a cold snap is exactly the scenario the Fitness for Human Habitation Act was written for.

Serviceteam works with landlords and letting agents across London on exactly this basis — fast turnaround, documented compliance work, and engineers who know the Potterton range well.

Resetting Your Potterton Boiler Safely

Most Potterton faults ask for a reset once the underlying cause is sorted — pressure topped up, pipe thawed, power stable again. The process is similar across most current models: press and hold the reset button for around 3 to 5 seconds until the display cycles back to normal. Always check your specific model's instructions, as the exact procedure can vary.

A couple of things worth knowing. Only reset once, and only after you've actually addressed what triggered the fault in the first place. Resetting a boiler repeatedly without fixing the cause won't clear the code for good, and on some faults it can mask a bigger problem building underneath. If a single reset doesn't hold, stop and get it looked at rather than cycling the reset button.

When to Call a Gas Safe Engineer

Some Potterton faults are genuinely DIY-friendly — E1 with a filling loop, E133 with some warm towels and patience. Others aren't, and trying to push past a fault that keeps returning usually just delays the actual fix. Call a professional if:

• The fault code returns immediately after a reset
• You can't find or access the component the fault points to (condensate pipe, filling loop, PCB)
• There's visible damage — a cracked pipe, water pooling near the boiler, scorch marks
• You're getting E168, E125, E160, E110, or E28/E29 codes, since these usually involve internal electrical or mechanical parts
• You're simply not comfortable working near a gas appliance, which is completely reasonable

Gas Safe registration is a legal requirement for anyone working on a gas boiler in the UK, so it's worth checking an engineer's registration before they start, not after.

Preventing Future Potterton Faults

A lot of the fault codes on this page are avoidable with a bit of upkeep:

• Insulate the condensate pipe — foam sleeves or waterproof tape on any external run stops most E133 lockouts before they start
• Check pressure seasonally — a quick glance at the gauge before winter catches an E1 fault before it happens
• Book an annual service — a Gas Safe engineer checking the system once a year catches early signs of pump wear, ignition issues, and PCB faults before they cause a lockout
• Don't ignore intermittent faults — a code that clears itself and comes back is still worth investigating, even if it's not stopping the heating yet

Regular servicing is one of the biggest factors in avoiding an emergency call-out mid-winter, which is exactly when boiler faults are least convenient and engineers are busiest.

Get Your Potterton Boiler Fixed Today

Whatever code your Potterton boiler is showing, you don't have to sit with a cold house while you figure it out. Serviceteam's Gas Safe registered engineers cover Potterton boilers across London. If you've worked through the steps above and the fault hasn't cleared, or you'd rather have someone qualified handle it from the start, get in touch with our boiler repair London team and we'll get an engineer out to sort it.

Frequently Asked Questions

What Does a Flashing Light Mean Instead of a Fault Code on My Potterton Boiler?

Not all Potterton faults show as an E-code straight away. Some older or entry-level models use a flashing light or symbol before a full code appears. Treat a flashing light the same way as a code — check your manual for what the pattern means, and if it's not clear, call an engineer rather than guess.

Can I Keep Resetting My Potterton Boiler Until the Fault Clears?

You can reset it, but repeated resets without addressing the cause won't fix anything long-term and can make some faults harder to diagnose once an engineer arrives, since the fault history gets wiped each time. One reset after addressing the likely cause is reasonable. Beyond that, stop and get it checked.

How Do I Find My Potterton Boiler's Model Number?

It's usually printed on a data badge inside the front panel of the boiler, or on the original installation paperwork. Having the model to hand when you call an engineer or search for your fault code helps narrow down the exact cause, since some codes carry slightly different meanings across the Potterton range.

Is a Potterton Fault Code Covered by My Boiler Warranty?

If your boiler is still within its manufacturer warranty period and was serviced annually by a Gas Safe engineer, most fault-related repairs are covered. Check your warranty documentation or contact Potterton directly to confirm what's included before booking an independent repair, so you don't end up paying for something that would have been covered.