Intergas 30 Fault Code: Causes, Fixes & Repair Costs
What does the Intergas 30 fault code mean?
Fault code 30 on an Intergas boiler points to a problem with the gas valve relay. The relay is a small electrical switching component within the gas valve assembly that the PCB uses to open and close the valve, controlling the flow of gas to the burner. When the boiler's control system detects that this relay is behaving unexpectedly — either not switching correctly or sending back an unexpected signal — it triggers a safety lockout and displays code 30. Because the fault is directly linked to the gas circuit, the boiler will not operate again until the underlying problem has been identified and resolved by a Gas Safe registered engineer.
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
- Faulty or failed gas valve relay Common
The relay inside the gas valve is the most frequently diagnosed cause of fault code 30. Over time, the relay contacts can burn, corrode, or fail to switch reliably. When the PCB sends the signal to open the valve and gets no response — or an unexpected one — the boiler locks out as a precaution.
- Wiring or connector fault between PCB and gas valve Common
Damaged wiring, a corroded connector, or a loose plug between the main PCB and the gas valve can mimic a relay failure. The PCB may interpret the broken circuit as the relay not responding and trigger code 30 even if the valve itself is in good working order.
- Incorrect gas valve calibration or adjustment Sometimes
The gas valve must be set to deliver the correct gas rate to the burner. If the valve has drifted out of calibration — for example, following a previous repair or due to wear — the burner performance degrades and the boiler's monitoring system may eventually flag a fault and lock out.
- Faulty or damaged PCB Sometimes
If the PCB itself is defective, it may be unable to send or read the correct switching signals to the gas valve relay. In this scenario the valve and relay can be perfectly serviceable, but the control board cannot communicate with them properly. PCB failure is less common but should be investigated if all valve-side checks come back clear.
- Water ingress or internal boiler leak Rare
Internal leaks from pump seals, heat exchanger joints, or loose component connections can cause water to track onto the PCB or gas valve wiring, leading to short circuits and intermittent faults. If code 30 is appearing on a relatively new boiler, water damage is worth investigating as the root cause.
How to fix it
- Do not attempt to reset the boiler repeatedly DIY safe
Because code 30 is a gas-circuit lockout, repeatedly pressing the reset button will not clear the underlying fault and could mask the problem. Avoid resetting more than once while you wait for an engineer.
- Check that your gas supply is working DIY safe
Confirm that other gas appliances in your home — such as a gas hob or a neighbour's supply — are working normally. If you have no gas at all, contact your gas network provider (Cadent, SGN, or similar) rather than a boiler engineer. If you smell gas at any point, do not operate any switches, leave the property, and call the National Gas Emergency Service on 0800 111 999.
- Check for any obvious signs of a leak around the boiler DIY safe
Look around the base of the boiler casing and at visible pipework for signs of dripping water or damp patches. If you spot a leak, turn off the boiler and water supply and note the location for your engineer — this information will help them diagnose quickly.
- Engineer: inspect all wiring and connections to the gas valve Gas Safe engineer
A Gas Safe engineer should start with a thorough visual check of all wiring looms, plugs, and connectors running between the PCB and the gas valve. Burnt contacts, corrosion, or a loose plug are quick wins that can resolve the fault without component replacement. Each wire should then be tested with a multimeter for continuity and correct voltage.
- Engineer: test and inspect the gas valve relay Gas Safe engineer
With wiring confirmed good, the engineer should test the relay itself, checking that it switches correctly when energised and that resistance readings fall within the manufacturer's specification. A relay that fails to switch or shows a short circuit confirms the gas valve needs repairing or replacing.
- Engineer: check and adjust gas valve calibration Gas Safe engineer
The engineer should verify that the valve is delivering the correct gas rate at both minimum and maximum modulation using appropriate gas test equipment. If calibration has drifted, adjusting it to the manufacturer's specified settings may resolve the fault without a full replacement.
- Engineer: replace the gas valve if found to be defective Gas Safe engineer
If relay testing and calibration checks confirm the valve is beyond adjustment, the engineer will replace it with a compatible unit. After fitting, gas rates must be re-checked and the boiler recommissioned in full before returning it to service.
- Engineer: replace the PCB if valve and wiring checks are inconclusive Gas Safe engineer
Should all gas valve and wiring tests come back clear, attention should turn to the PCB. A defective control board may be sending incorrect switching signals. PCB replacements for Intergas boilers typically need to be ordered from a specialist supplier on a next-day basis, so a return visit is usually required.
- Call a Gas Safe registered engineer if you have not already done so DIY safe
All diagnostic and repair work on the gas valve, relay, wiring, and PCB must be carried out by a Gas Safe registered engineer. You can find one at gassaferegister.co.uk. Always ask to see their Gas Safe ID card before any work begins.
Parts you may need
- Intergas gas valve assembly · from £110
- Gas valve relay (standalone component) · from £25
- Intergas main PCB · from £220
- Wiring loom / connector harness · from £35
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 £150–£380, depending on the underlying cause.
Frequently asked questions
Is fault code 30 on an Intergas boiler dangerous?
Any fault that involves the gas valve should be taken seriously. The boiler locks itself out as a safety measure to prevent uncontrolled gas flow, so the risk is managed, but you should still call a Gas Safe registered engineer promptly rather than repeatedly resetting the appliance. If at any point you smell gas, do not touch any switches, leave the building immediately, and call the National Gas Emergency Service on 0800 111 999.
Can I reset my Intergas boiler to clear fault code 30?
You can try a single reset, but code 30 is caused by a hardware fault in the gas valve circuit — pressing reset will not fix the underlying problem and the boiler will almost certainly lock out again. If one reset does not clear the fault, stop there and arrange for a Gas Safe engineer to investigate. Repeated resetting on a gas-circuit fault is not recommended.
How much does it cost to fix Intergas fault code 30?
For most households the repair involves replacing the gas valve or addressing a wiring fault, which typically comes to between £150 and £380 including labour and parts. If the PCB also needs replacing the bill can rise to around £450–£500 once parts and labour are included. In rare cases involving water damage to multiple components, costs can be higher — at which point your engineer may discuss whether a new boiler is more economical.
Is my Intergas boiler still under warranty?
Intergas boilers come with a minimum 12-month warranty as standard, but many models qualify for extended cover of 3 to 10 years when registered and installed by an approved installer. Check your installation paperwork or the Intergas website to confirm your warranty status before paying for any repair — if the boiler is still within its warranty period, parts and labour may be covered at little or no cost to you.
Why does fault code 30 sometimes appear alongside fault code 29 on Intergas boilers?
Intergas documentation groups codes 29 and 30 together under the same gas valve relay fault category. Code 29 typically relates to the relay being detected in an unexpected state before the burner fires, while code 30 is recorded when the relay fault is confirmed during or after a firing attempt. In practice both codes point to the same area — the gas valve relay, its wiring, or the PCB — and the diagnostic and repair approach is identical for both.