Main Eco Compact E133 fault code: gas supply fault
The Main Eco Compact E133 fault code means “Gas supply fault” in Baxi’s current error-code table. The table includes Main Eco Compact Combi and Main Eco Compact System boilers in the applicable model group.
The Main Eco Compact manuals give broader context: E133 can indicate an interruption of the gas supply, failed ignition or that the flame was not detected. These descriptions are compatible, but the code does not tell a homeowner which condition applies or which part may be involved.
What happens when E133 appears?
A gas boiler must have an available gas supply, complete its ignition sequence and confirm a flame. If that sequence does not complete safely, the controls stop firing and show a lockout code.
E133 is the message associated with that failed sequence on this range. It can leave the home without heating and, on a combi boiler, without hot water.
The display does not safely identify a gas-pressure issue, valve problem, electrode fault, cable fault, burner problem or other internal cause. Baxi’s professional table mentions checks involving the power supply, sensing electrode, spark electrode and cable; those are installer actions, not homeowner instructions.
What you may notice
Alongside E133, you may find:
- the boiler attempts to start but does not fire;
- heating and hot water are both unavailable;
- the boiler works briefly after a reset and locks out again;
- another gas, ignition or flame code appears;
- other gas appliances are also unavailable; or
- the problem follows a supply interruption, meter issue or very cold weather.
These details help describe the pattern, but they do not prove the cause. Do not repeatedly operate other gas appliances merely to test the supply.
If the boiler will not fire, [safe checks before calling an engineer](/boiler-help-boiler-not-firing-up/) gives useful external observations. If it works after a reset and then stops again, [why repeated boiler resets are not a repair](/boiler-help-boiler-resetting-itself/) explains the next step.
Is E133 only a gas-supply problem?
The current Baxi table labels E133 as a gas supply fault. The Main Eco Compact manual also says the code may appear when ignition has failed or the flame has not been detected.
Baxi’s homeowner guidance notes that a frozen condensate pipe can produce E133 on some boilers. That is relevant in freezing weather, but it should not be assumed. Only consider it when you can safely identify an exposed plastic condensate pipe and follow Baxi’s official homeowner method. Never pour boiling water over it, climb or dismantle pipework.
If the weather is not freezing, the pipe is inaccessible or you are unsure what you are looking at, leave it alone and arrange repair.
Is E133 the same as E128?
No. Baxi’s current table lists:
- E133 as a gas supply fault; and
- E128 as a safety error for frequent loss of flame.
The Main manual similarly separates a supply or ignition failure from flame failure during normal operation. Record the exact number, because the point at which the firing sequence failed matters.
Does E133 apply to every Main boiler?
No. Fault-code meanings and reset methods vary by range. The current Baxi table includes Main Eco Compact Combi and Main Eco Compact System in the E133 model group, and both Main Eco Compact manuals include the code.
Confirm the full model name on the appliance or in its paperwork. Do not copy instructions for an unrelated Main boiler that happens to show a similar number.
Safe checks before booking repair
Keep the casing closed. You can:
- Record the exact code and model. Photograph the display.
- Check for a wider outage. Look for an official gas-supplier or network notice rather than repeatedly trying appliances.
- Check a prepayment meter externally. If applicable, note whether it shows credit or a supply message; do not open or alter the meter.
- Confirm electrical power. Note whether the boiler display is on and whether there was a recent power cut.
- Note the demand. Was the boiler serving heating, hot water or both?
- Record recent work. Mention meter, boiler, gas-supply or condensate work by a professional.
- Consider freezing weather. Note whether a visible external condensate pipe appears frozen, but do not touch inaccessible pipework.
- Preserve other codes. Write down their order.
If you smell gas at any point, stop checking and follow the emergency action below.
What not to do
Do not:
- remove the boiler casing;
- work on the gas meter or gas pipe;
- adjust the gas valve or gas pressure;
- clean or move the burner;
- touch spark or sensing electrodes;
- unplug cables or test wiring;
- inspect combustion or the flue;
- enter installer settings; or
- repeatedly reset the boiler.
Never use a naked flame to test whether gas is available. Do not attempt to light the boiler manually.
Can I reset E133?
The Main Eco Compact manuals include E133 among the resettable lockout codes. Baxi’s reset guide also says frequent lockout indicates a fault that needs an installer or service engineer.
If the exact display shows the R symbol, the exact model guide permits a reset and there is no gas smell, carbon-monoxide alarm, soot, smoke or scorching, try one reset. If E133 returns, stop. Repeated resets will not restore a failed supply or correct an ignition or flame-safety problem.
If the display shows a spanner rather than R, the user guide says to contact support rather than reset it.
When to arrange professional repair
Book a repair when:
- E133 remains after one permitted reset;
- it returns;
- no network outage or simple meter message explains the loss of supply;
- heating or hot water is unavailable;
- another safety code appears; or
- you are unsure whether the appliance is safe.
Tell the engineer about the exact model, the full code, recent supply events and whether the fault occurs on heating, hot water or both.
Gas and carbon-monoxide emergency action
If you smell gas, do not use electrical switches, mobile phones inside the property or naked flames. Open doors and windows if it is safe, leave the property and call the National Gas Emergency Service on 0800 111 999 from a safe place.
If a carbon-monoxide alarm sounds, or anyone has headache, dizziness, nausea, weakness or confusion, move into fresh air, seek medical help and do not use the boiler until it has been checked by a suitably qualified Gas Safe registered engineer.
Choose a clear booking route that aims to fix the E133 fault and restore dependable heating and hot water.
Quick Answers
What does Main Eco Compact E133 mean?
Baxi’s current table calls it a gas supply fault. The Main manuals add supply interruption, ignition failure or flame not detected.
Does E133 prove the gas valve is broken?
No. The code does not identify a failed component.
Can a frozen condensate pipe cause E133?
Baxi says it can on some boilers. Only follow official homeowner guidance if the exposed pipe is safely accessible and genuinely frozen; never use boiling water.
Can I reset E133?
If the exact display shows R and your exact guide permits it, try once. If E133 returns, arrange repair.
Should I test another gas appliance?
Do not repeatedly operate appliances as a test. Check official outage information or a visible meter message instead.
What if I smell gas?
Leave the property and call 0800 111 999 from a safe place. Do not reset the boiler.
Do I need a Gas Safe engineer?
Yes if the code remains or returns, or no simple external supply issue explains it.