Potterton Boiler Repairs London

Potterton Boiler Repair Help Centre

Common Potterton faults, fault codes, safe checks, and when to call a Gas Safe engineer.

We specialise in Potterton boiler repairs across London.

Gas Safe registered engineers for safe diagnosis, repair and testing.

24/7 availability with London-wide call handling and booking.

Jump to: Fault Codes · E133 Fault · Pressure · Frozen Condensate · Repair or Replace

Quick Checks Before You Call Anyone

These take 60 seconds and solve a surprising number of lockouts:

1. Check the pressure gauge: If below 1 bar, top up (see guide below). More detail in our complete pressure guide.
2. Note the fault code: Potterton displays show codes like E133, E119, E125. Write it down before calling.
3. Check your fuse box: Boilers need electricity; a tripped switch is an easy fix.
4. Check thermostat and timer: Settings can change after clock changes or power cuts.
5. Freezing weather? The condensate pipe may be frozen (see winter section below).
6. Reset once only: Press the reset button on the front panel once, wait 60 seconds. If it locks out again, stop and call an engineer.

Potterton Fault Codes

Note: Potterton is part of the Baxi Group, so many fault codes are shared across platforms. Older Potterton models may use different codes or indicator lights. If unsure, call us and we will help you identify your specific code.

E133: Ignition Failure

What is happening: The boiler is trying to ignite but cannot establish a flame after multiple attempts. This is the most common Potterton fault code.

Common causes: Frozen condensate pipe (winter), gas supply interruption, faulty ignition electrode or lead, blocked or damaged flue, gas valve fault.

What to try: Check if your gas hob or other gas appliances work. In freezing weather, check the condensate pipe for ice. If gas supply is fine but the boiler will not ignite, call an engineer.

Note: On older Potterton models like the Profile and Suprima, ignition components wear over time. These are common repair items.

E125: Circulation Fault

What is happening: The boiler is not detecting adequate water flow through the heat exchanger.

Common causes: Pump failure, airlocks in the system, blocked or restricted pipework, sludge build up, faulty flow sensor.

What to try: Check if radiators are heating. If some are cold at the bottom, there may be sludge. If the pump is not running (no vibration or noise), call an engineer. A power flush may be needed if sludge is suspected.

E119: Low Water Pressure

What is happening: System pressure has dropped below the minimum operating level.

Common causes: Small leak in system, recently bled radiators, pressure relief valve discharge, expansion vessel needs recharging.

What to try: Top up pressure using the filling loop (see below). If pressure drops again within days, there may be a leak. Read our pressure guide for step by step instructions.

How to Top Up Pressure (Potterton)

If you are not comfortable using the filling loop, stop and call a Gas Safe engineer.

Do not remove the boiler casing. If you cannot locate the filling loop easily, call an engineer.

1. Locate the filling loop (usually underneath the boiler, a braided silver hose with one or two valves).
2. Ensure the boiler is off and cool.
3. Open the valves slowly, a quarter turn at a time.
4. Watch the pressure gauge rise to between 1.0 and 1.5 bar.
5. Close both valves fully.
6. Switch the boiler back on.

Do not exceed 2.0 bar. If you overfill, stop and call an engineer.

If you need to top up frequently (more than once a month), there is likely a leak. Call us for a diagnosis.

Frozen Condensate Pipe (Winter)

In freezing weather, a frozen condensate pipe is one of the most common causes behind E133 and E128 lockouts on Potterton boilers. This is often safe to resolve with the steps below. If you are unsure, or the boiler will not restart, call an engineer.

Signs: Boiler locked out with E133 or E128, freezing temperatures outside, gurgling sound when boiler tries to start.

What to do:

1. Locate the condensate pipe (white or grey plastic pipe exiting to an outside drain).
2. Pour warm water (not boiling) over the frozen section.
3. Reset the boiler once thawed.

Full instructions: Frozen condensate pipe guide.

If it keeps happening, we can reroute the pipe internally or add insulation to prevent future freezing.

Why These Faults Are Common in London Homes

Hard water, older pipework, and winter weather make certain faults more likely in London properties:

• E133 ignition failures: Frozen condensate pipes during cold snaps are a frequent cause. Older Potterton models also have ignition components that wear over time.
• E125 circulation faults: London’s hard water causes sludge and limescale build up, restricting flow and triggering circulation errors.
• Pressure fluctuations: Older London properties with microbore pipework or poorly balanced systems experience more E119 low pressure faults.
• Older boiler stock: Many London properties still have Potterton Profile, Suprima, or Performa models that are now reaching end of life.

Potterton Models We Repair

We repair Potterton gas boiler models including:

• Assure: Current combi range
• Titanium: Premium combi and system range
• Promax: Popular combi range (now discontinued but widely installed)
• Gold: Heat only and system boilers
• Suprima: Older heat only range, parts becoming limited
• Profile: Older combi range, parts availability varies
• Performa: Older range, some parts constraints

We carry common Potterton parts and can source others. Older models may have longer parts lead times.

Common Potterton Problems

Ignition failures (E133): Often caused by worn electrodes, faulty spark generator, or gas valve issues on older models.

Fan faults (E160): Fan not running at correct speed or failing to prove to the PCB.

Diverter valve sticking: Hot water works but radiators stay cold, or vice versa. More common on older combis.

PCB failure: Random lockouts, display glitches, or complete failure. Can be expensive on older models where PCBs are scarce.

Heat exchanger blockage: Kettling noises, overheating, reduced efficiency. See our guide to boiler noises.

Repair or Replace?

Potterton boilers typically last 12 to 15 years with proper maintenance. If yours is approaching that age and needs a major repair (heat exchanger, PCB), replacement may be more cost effective.

Older models like the Suprima, Profile, and Performa can be difficult to source parts for. If you have one of these and it needs a major repair, replacement may be the most practical option.

We give honest advice either way. Read more: Repair or replace? An engineer’s guide.

If you decide on a new boiler: New boiler installation.

Potterton Servicing

Annual servicing keeps your Potterton running efficiently and helps maintain warranty terms. We service Potterton models and provide a clear report after each visit.

We recommend servicing in late summer or early autumn, before the heating season. Book your boiler service.

Renting? Landlords: Check This

Tenants: Your landlord is usually responsible for boiler repairs. Contact them first and keep written records, especially if you have no heating or hot water.

Landlords: Stay compliant with our Gas Safety Certificate (CP12) service. See our full London landlord checklist covering gas safety, EPCs, and maintenance requirements.

London Wide Coverage

We repair Potterton boilers across all London boroughs. For coverage and service areas, see our London coverage page.

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