Potterton Boiler Error Codes: Common Faults & Reset Procedures

Quick Answer: Potterton boilers (Promax, Titanium, Gold, Performa) are part of the BDR Thermea UK group (same parent as Baxi and Main). Most Potterton fault codes are shared with the Baxi platform: E133 (ignition failure), E119 (low pressure), E125 (flue/fan fault), and E168 (internal fault). Reset by holding the reset button for 3 seconds. Codes may be displayed as "E" numbers or as LED flash sequences on older models.

Summary

Potterton is one of the oldest and most recognised UK boiler brands, with a history stretching back to 1850. In the modern era, Potterton boilers are manufactured by BDR Thermea UK — the same group that produces Baxi and Main boilers — and the Promax and Titanium ranges share significant engineering and components with their Baxi equivalents.

This shared platform means that Potterton fault codes, spare parts, and diagnostic procedures are largely identical to Baxi codes. Engineers familiar with Baxi boilers will find Potterton diagnostics very familiar. The Promax series (Promax 24, 28, 35) is the most commonly encountered Potterton combi in UK domestic properties.

Older Potterton models (Performa, Gold) used a different code scheme with LED flash sequences rather than digital displays — the number of flashes indicated the fault type. These older models are now 15+ years old and may be approaching end-of-life. Parts availability for the oldest Potterton models can be limited.

Key Facts

• BDR Thermea platform — Potterton shares engineering and parts with Baxi and Main; most fault codes are identical across the three brands
• Promax range — Potterton's most common modern combi; Promax 24, 28, 35 combi; Promax HE A (system boiler)
• Titanium range — higher specification; ErP A-rated; compatible with weather compensation
• Reset procedure — press and hold the reset/flame button for approximately 3 seconds until the display changes
• LED flash codes (older models) — Performa and Gold series show fault codes as LED flash patterns; count the flashes (see table below)
• E133 — the most common fault across all BDR Thermea boilers; ignition failure; check gas, electrodes, and condensate
• E119 — low system pressure (below approximately 0.5–0.8 bar depending on model); repressurise via filling loop
• E128 — fan circuit fault; fan bearing, PCB fan control, or wiring
• E131 — pressure switch fault; check condensate, check flue
• Baxi Technical Helpline — 0344 871 1525 covers Potterton; engineer technical support available
• Warranty — Potterton offers 2-year standard warranty; 5 or 7 years with registration; requires annual service evidence

Fault Code Reference Table

Older Potterton LED Flash Codes (Performa, Gold)

Detailed Guidance

Reset Procedure

Promax and Titanium (digital display):

1. Identify the fault code on the LCD display.
2. Locate the reset button — on Promax models, this is typically a push button marked with a flame or "R" symbol on the right side of the facia.
3. Press and hold for 3 seconds. The display will change and the boiler will attempt a restart.
4. If the fault returns immediately, do not reset repeatedly — investigate the cause.

Performa and Gold (LED indicator):

1. Count the number of LED flashes carefully — allow for the gap between flash sequences.
2. Compare with the table above.
3. The reset is typically a press of the central control button or by switching the boiler off and on at the isolator.

E133 — Ignition Failure on Potterton

E133 is the BDR Thermea group's standard ignition lockout code, shared across Potterton, Baxi, and Main boilers. The diagnostic approach is identical across all three brands.

E133 DISPLAYED
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     v
Gas supply check:
- Test other gas appliances
- Check gas meter not in credit lockout (PAYG meter)
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Cold weather: check condensate pipe
- Frozen condensate is the #1 cause in winter
- Locate condensate pipe (usually 22mm white plastic pipe from boiler to drain or external)
- If external pipe shows ice/frost: pour warm water over it; consider lagging
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     v
Access burner area (Gas Safe engineers only for gas components):
- Inspect ionisation electrode (flame sensor)
- Inspect spark electrode
- Check HT ignition lead
- Clean contaminated surfaces with fine emery paper
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     v
Reset and observe:
- Does boiler fire, then go out (flame failure)?
  YES: gas valve operation or combustion issue -- Gas Safe engineer
- Does boiler never spark?
  YES: electrode, PCB spark circuit
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     v
Gas Safe engineer: combustion analysis, gas valve operation test

E119 — Low Pressure on Potterton

The Potterton E119 is the low pressure lockout, same as Baxi E119.

The standard pressure recovery procedure:

1. Check the gauge — if below 1 bar, top up.
2. Filling loop location on Promax: look inside the front bottom panel. The filling loop is typically a flexible stainless steel hose with two blue-handled quarter-turn valves.
3. Open both valves until pressure reaches 1.0–1.5 bar; close both.
4. Press reset.

If the boiler needs topping up regularly, check the expansion vessel:

• Locate the expansion vessel — in the Promax, it is typically behind the front panel, accessible from below. It has a Schrader valve.
• With the boiler cold and system at 0 bar, test the Schrader: if water comes out, the bladder is ruptured and the vessel needs replacement.

Condensate Pipe Management

All modern Potterton boilers are condensing models and produce acidic condensate. The condensate pipe is the most common cause of boiler lockout in cold weather.

Preventing winter condensate freeze:

• Ensure any external run of condensate pipe is as short as possible
• Insulate external condensate pipe with 25mm waterproof foam lagging (not standard pipe lagging — it must be waterproof to resist moisture)
• Consider re-routing to an internal drain if the external run is long
• In very cold spells, the building owner can use warm water to thaw a frozen pipe; this is not a gas work activity

Temporary condensate thaw: Pour warm (not boiling) water along the condensate pipe. Do not use a heat gun or flame. Once the pipe is flowing, reset the boiler. The lockout will clear automatically.

Frequently Asked Questions

Potterton vs Baxi — are they the same boiler?

They share a common platform (BDR Thermea group), common components, and common fault codes. The external casing and brand identity differ, and some models have slightly different configurations. A Gas Safe engineer familiar with Baxi will have no trouble servicing a Potterton, and most Baxi spare parts are cross-referenced to Potterton equivalents.

My Potterton Performa keeps flashing 3 times — what should I check?

Three flashes on a Performa indicates a high-limit thermostat operation (overheat). The most common causes are: (1) pump failure — check the pump is running; (2) all TRVs closed simultaneously — ensure at least one radiator circuit (the hallway, landing, or one radiator) does not have a TRV and remains open at all times; (3) magnetite (sludge) blocking the heat exchanger — consider a powerflush if the system has not been flushed recently.

The Potterton Promax shows E133 every morning in winter — is this normal?

No. This is the frozen condensate pipe pattern — very common in UK winters. The solution is to lag the condensate pipe properly. A permanently frozen condensate pipe every cold morning means the pipe is too exposed. Consider running it internally if possible, or installing trace heating on the external section.

How do I access the service manual for my Potterton boiler?

The model number and serial number are on a label inside the front panel or on the back of the boiler. Go to the Potterton website (www.potterton.co.uk) or the Baxi website (same group) and enter the model number to download the Installation and Servicing Instructions. Alternatively, call the BDR Thermea technical helpline: 0344 871 1525.

Regulations & Standards

• Gas Safe Register — mandatory for all gas work; Potterton boilers are regulated gas appliances

• Building Regulations Part J — combustion appliances requirements

• BS EN 677:1998 — gas-fired condensing boilers

• Potterton Warranty Terms — annual service required to maintain warranty validity

• Potterton UK: Technical resources — manuals and fault code documentation

• BDR Thermea Technical Helpline — 0344 871 1525 (engineers)

• Gas Safe Register — find a registered Gas Safe engineer

• baxi — Baxi error codes (shared platform)

• main — Main boiler error codes (shared platform)

• boiler losing pressure — E119 pressure fault detailed diagnosis

• powerflush — system cleaning for overheat and flow faults