Andrews E30 Fault Code: Causes, Fixes & Repair Costs
What does the Andrews E30 fault code mean?
On Andrews commercial water heaters and boilers, fault codes follow a two-part structure: a letter prefix that tells you the fault category, and a number that identifies which burner module is affected. The letter 'E' indicates a blocking fault — meaning the appliance has suspended normal operation but has not necessarily locked out permanently — while 'A' would indicate a full lockout. The number '30' most likely refers to burner module 30 on multi-module commercial units such as the MAXXflo or HIflo EVO range. The precise nature of the blocking condition — whether it relates to ignition failure, an overtemperature event, or a flue/ventilation issue — depends on your specific model's fault code table. Retrieve the manual from andrewswaterheaters.co.uk or ManualsLib and cross-reference the E30 entry for your exact unit. In practice, the three most common root causes across Andrews commercial ranges are a burner ignition or flame-detection failure, an overheat safety trip, and a flue or exhaust ventilation fault. All diagnosis and repair must be carried out by a Gas Safe registered engineer with commercial appliance qualifications.
General guidance only — not a substitute for professional advice, and not certified by a Gas Safe engineer. Always have your specific appliance assessed by a qualified professional. Any gas work must be carried out by a Gas Safe registered engineer. If you smell gas or suspect carbon monoxide, leave the property and call the National Gas Emergency line on 0800 111 999.
Common causes
- Burner ignition or flame detection failure Common
The burner module identified by the code failed to ignite or the flame sensor did not confirm a stable flame within the allowed attempt window. This can be caused by a fouled or corroded ignition electrode, a contaminated flame sensor rod, a weak spark transformer, or a momentary interruption to the gas supply. On multi-module Andrews units this is the most frequently reported root cause of an E-prefix blocking fault.
- Overheat safety trip Common
An overheat thermostat or high-limit sensor on the identified module has tripped because water temperature exceeded its safe threshold. Common triggers include scale and limescale build-up inside the heat exchanger restricting flow, insufficient cold-water inlet flow rate, a stuck or faulty modulating thermostat, or a pump fault causing hot water to stagnate. Andrews commercial units often serve high-demand sites where flow rate problems develop gradually.
- Flue or exhaust ventilation fault Sometimes
The appliance's combustion management system has detected inadequate exhaust flow or back-pressure in the flue circuit. Causes include a blocked flue terminal (bird nesting, debris, ice in winter), a failed or stalling flue fan motor, collapsed or disconnected sections of flue duct, or a wiring fault on the fan proving circuit. Poor ventilation to the plant room can also starve the burner of combustion air and trigger this type of blocking code.
- Scale and sediment accumulation Sometimes
Heavy limescale deposits inside the heat exchanger reduce thermal transfer efficiency and restrict water flow, forcing the unit to work harder and raising internal temperatures. On Andrews commercial units serving hard-water areas without adequate water treatment, scale build-up can degrade performance gradually until a blocking fault is triggered. Annual descaling forms part of the recommended service schedule.
- PCB or wiring fault on the burner module Rare
A fault on the control board governing burner module 30, or damaged wiring in the module's harness, can cause the controller to report a blocking condition even when gas supply, ignition components, and flue are all serviceable. This is a diagnosis-of-exclusion finding and is less common than mechanical or combustion causes.
How to fix it
- Check that the gas supply to the building is live DIY safe
Confirm that other gas appliances on the same supply — such as a gas hob or another boiler — are working normally. If there is a site-wide gas outage, contact your gas supplier. Do not attempt to investigate gas pipework yourself.
- Inspect the flue terminal for obvious external blockages DIY safe
If the flue terminal is safely accessible from ground level or a walkway, visually check for debris, bird nesting material, or ice blocking the outlet. Do not climb onto roofs or work at height to do this. Do not probe inside flue ducts.
- Allow the unit to cool before attempting a reset DIY safe
If an overheat trip is suspected, give the appliance at least 15–20 minutes to cool before touching the reset. Attempting to restart a hot unit repeatedly can cause further damage or mask the underlying cause.
- Reset the appliance using the control panel reset function DIY safe
Follow the reset procedure described in your unit's operator manual — typically holding the reset button for a few seconds until the display clears. Limit resets to two or three attempts. If the E30 code returns immediately or after a short run, stop resetting and call an engineer; repeated resets without fixing the fault can damage ignition components.
- Retrieve the full fault history from the control panel DIY safe
Many Andrews commercial controllers store a fault log. Note down any additional codes displayed alongside E30, including any sub-codes or module identifiers, and have these ready for the attending engineer. This significantly speeds up diagnosis.
- Commission a Gas Safe registered commercial engineer to carry out full diagnosis Gas Safe engineer
A qualified engineer should inspect the ignition electrode and flame sensor on module 30, check spark output, verify gas pressure and valve operation, inspect the flue and fan circuit, measure water flow rate, and check for scale in the heat exchanger. All of these tasks require Gas Safe registration and, for commercial Andrews units, relevant commercial appliance competency. Do not attempt any of these checks yourself.
- Replace faulty components identified during diagnosis Gas Safe engineer
Depending on findings, the engineer may need to clean or replace the ignition electrode, replace the flame sensor, service or replace the flue fan motor, descale the heat exchanger, replace the gas valve, or replace the module control board. Only a Gas Safe registered engineer should carry out these tasks.
- Arrange an Andrews-approved annual service if not recently completed Gas Safe engineer
Andrews recommends annual servicing by a qualified commercial engineer. If the unit has not been serviced within the past 12 months, a full service alongside the repair will reduce the likelihood of repeat blocking faults and is often required to maintain any remaining warranty. Contact Andrews Water Heaters' after-sales team or an approved service agent such as Tech Asset Management (08455 194299) if you need a referral.
Parts you may need
- Ignition electrode (burner module) · from £45
- Flame sensor / ionisation rod · from £35
- Flue fan motor · from £180
- Gas valve (module) · from £220
- High-limit overheat thermostat · from £55
- Burner module control PCB · from £320
The exact spare depends on your boiler's GC number (on the data badge). Check this against the part before buying.
Typical repair cost
Expect to pay roughly £180–£550, depending on the underlying cause.
Frequently asked questions
Is the Andrews E30 code a full lockout or can the boiler recover on its own?
The 'E' prefix in Andrews fault code notation indicates a blocking fault rather than a hard lockout. This means the appliance has suspended burner operation as a precaution but may attempt to restart once the triggering condition clears. An 'A' prefix would indicate a permanent lockout requiring a manual reset. However, even a blocking fault should be investigated by a qualified engineer — an appliance that repeatedly blocks and restarts is masking an underlying problem that will worsen over time.
Can I reset an Andrews commercial water heater myself?
The control panel reset is generally considered an operator-level action and is described in the user section of most Andrews manuals. You can attempt a reset once or twice after allowing the unit to cool, and after confirming the gas supply is on and there is no obvious external flue blockage. However, if the E30 code returns after resetting, you must call a Gas Safe registered engineer with commercial appliance experience. Repeated resets without fixing the fault are not safe and may void your warranty.
How much does it typically cost to repair an Andrews commercial water heater showing E30?
Most E30 faults are resolved by cleaning or replacing ignition components, servicing the flue fan, or descaling the heat exchanger — repairs that typically fall in the £180–£550 range including parts and labour for a commercial appliance call-out. More complex repairs, such as replacing a gas valve (around £150–£300 for the part alone) or a module PCB (£300–£400 for the part), will push costs higher. Heat exchanger replacement on a large commercial unit can exceed £800–£1,200 including labour, and in those cases it is worth comparing against a new unit installation. Andrews units carry a two-year parts-and-labour warranty if commissioned by Andrews Water Heaters — check with their after-sales team before paying for any repair.
What is the difference between an 'E' fault and an 'A' fault on an Andrews MAXXflo or HIflo EVO?
Andrews commercial units use 'A' to denote a lockout fault — a condition the appliance cannot recover from without a manual reset by an operator or engineer. 'E' denotes a blocking fault, which is a temporary suspension of operation that may clear if the triggering condition resolves. The number that follows (in this case 30) identifies the burner module where the fault originated, which is particularly useful on multi-module MAXXflo units where individual modules can be isolated while the rest of the bank continues to operate. Always cross-reference the number against the fault code table in your specific model's manual for the precise fault description.