State Water Heater E133 Error — What It Means
E133 is not a documented error code for State brand water heaters. State water heaters typically use different fault codes (such as E10 for ignition failure). The E133 code is consistently documented as an ignition lockout fault on Baxi, Potterton, and Main gas-fired boilers, not water heaters. If your appliance displays E133, first confirm the brand and model by checking the rating plate. You may have misread the code, or your unit may actually be a combi boiler rather than a traditional water heater.
If you do have a Baxi, Potterton, or Main boiler showing E133, the code means the control board attempted to ignite the gas burner but the flame sensor did not detect a flame after multiple tries. This triggers a safety lockout to prevent unburned gas from accumulating. The fault typically occurs when gas flow is interrupted, the ignition electrode is dirty or damaged, or the gas valve fails to open properly.
Before You Replace Anything
Homeowners often replace the ignition electrode when the real problem is low gas pressure or a sticky gas valve. Check that other gas appliances work and verify the gas meter is on before ordering any parts.
Common Causes
- Faulty or sticky gas valve (~35%) The gas valve is blocked, corroded, or not opening enough to supply gas to the burner when the control board calls for ignition.
- Defective or dirty ignition electrode (~30%) The electrode that senses the flame is corroded, cracked, or coated with soot and fails to confirm a flame is present.
- Interrupted or low gas supply (~20%) The gas meter is turned off, prepay credit has expired, or supply pressure is too low due to a faulty regulator or meter issue.
- Damaged ignition leads (~10%) The wires connecting the ignition electrode are broken, have high resistance, or poor connections that prevent proper flame detection.
- Frozen condensate pipe (~5%) In rare cases, ice in the condensate drain pipe can indirectly prevent ignition by blocking exhaust flow or causing gas valve safety shutdowns.
Quick Diagnosis
Answer these to narrow it down fast.
Do other gas appliances in your home (such as a cooker or hob) light and work normally?
No: Check that the gas meter is on and, if you have a prepay meter, that it has credit. If the meter is on and other appliances still do not work, contact your gas supplier for a supply fault.
Does the boiler spark or click when you turn on the heating or hot water?
No: The control board may not be sending the ignition signal. Reset the boiler by turning it off for five minutes. If it still does not spark, the PCB or ignition module may be faulty.
Is the condensate pipe (white plastic pipe from the boiler to outside drain) exposed to freezing temperatures?
No: Frozen condensate is unlikely. Focus on gas supply and ignition system checks.
Step-by-Step Fix
- Verify the brand and model by reading the rating plate on your appliance. If it is a State water heater, E133 is not a standard code and you should consult the owner’s manual or wiring diagram for the correct fault list.
- Confirm gas supply by checking that the gas meter is on, the meter valve handle is aligned with the pipe, and other gas appliances (cooker, hob) work normally.
- Check prepay meter credit if you have a coin or card meter. Top up if needed and wait a few minutes for gas to flow again.
- Reset the boiler by turning it off at the control panel or wall switch, waiting five minutes, then turning it back on. Open a hot tap or turn on heating to create a demand before resetting.
- Inspect the condensate pipe if it runs outside in freezing weather. Warm any frozen sections gently with a warm water bottle or heat pack, repeating until the pipe is clear.
- Call a Gas Safe registered engineer if the fault persists. The engineer will remove and inspect the ignition electrode for dirt, corrosion, or cracks, test the ignition leads for continuity, measure gas pressure at the burner with a manometer, and test or replace the gas valve if faulty.
- Do not attempt to dismantle the burner assembly, adjust gas pressure, or replace the gas valve yourself. Gas work is regulated by law and must be carried out by a qualified engineer.
Parts Often Needed
| Part | Notes |
|---|---|
| Ignition electrode (flame sensor) | Amazon | Match the part number to your boiler model (Baxi, Potterton, or Main). Generic electrodes often do not fit correctly. |
| Gas valve | Amazon | Requires Gas Safe registered installation. Confirm the valve type and gas type (natural gas or LPG) before ordering. |
When to Call a Pro
Call a Gas Safe registered engineer immediately if you smell gas, if the boiler does not respond to a reset, or if you have already confirmed the gas supply is working but the fault persists. All work on gas valves, burners, ignition electrodes, and gas pressure testing is legally restricted to qualified engineers in the UK and many other countries. Attempting DIY repairs on gas appliances is dangerous and may void your warranty or home insurance. If your appliance is indeed a State water heater and not a Baxi or Potterton boiler, contact State customer service or a licensed plumber familiar with State products to interpret the error code correctly.
Rough cost: A pro service call runs about $150-300.