Error 119

Safety precautions:

- Do not work on gas or live mains circuits unless you are a qualified engineer. Isolate the boiler from the mains supply before removing covers (use the boiler isolator switch or the circuit breaker).

- Do not try to repair gas valves, burners, gas lines or sealed combustion parts. If you smell gas, leave the property and call the gas emergency number.

- If you are uncomfortable opening the boiler casing or handling electronics, stop and call a Gas Safe registered engineer.

Initial homeowner checks you can try safely:

1. Simple reset: switch the boiler off at the controller and isolator, wait 30 seconds, then turn back on. Some block conditions clear with a reset.

2. Check system pressure and obvious faults: confirm the boiler shows normal system pressure and there are no other obvious error symbols. If multiple faults are present, record them and report to your engineer.

3. Visual external check: look for loose plug-in controllers, wall thermostat batteries/connections and any obvious damage to external wiring. Do not open the boiler yet if you are not competent.

If you are technically competent and comfortable (qualified or confident with low-voltage electronics) follow these diagnostic steps (power off first):

1. Isolate mains power to the boiler and, if possible, turn off the gas supply.

2. Remove the boiler front cover following the manufacturer’s instructions to expose the PCB. Only do this if you know how and the boiler is isolated.

3. Locate the PCB and the connector labelled X2. The PCB silkscreen or service manual will show connector names; X2 is commonly a multi-pin plastic connector.

4. Inspect X2 pins 4 and 5 for a small jumper/link. The jumper is typically a removable plastic shunt that bridges the two pins. Check for:

- A missing jumper (physically absent), a broken/burnt jumper, or a jumper that is pushed off the pins.

- Corroded, bent or pushed-back pins or loose wiring on the connector.

5. Reseat any loose multi-pin connectors that plug into X2 and surrounding harnesses. Look for damaged wires or poor contacts.

6. If you find the jumper is simply displaced and you are confident it’s the correct component, you can refit a correct jumper. Use the exact type specified by the manufacturer – do not improvise with metal objects or incorrect links. If the jumper is missing or damaged, do NOT jury-rig a solution; source the correct part or call an engineer.

7. After checking/reseating, replace the cover, restore power and test the boiler. See if error 119 clears and the boiler operates normally.

If the error remains after the above or you find any of the following, stop and call a professional:

- Jumper is missing and you do not have the correct replacement part.

- Pins or connector are damaged, burnt or corroded.

- Faults persist after reseating connectors and resetting the boiler.

- You are unsure about any step, or you are not competent working inside the casing.

Why call a professional and when to call one:

- The X2 link and PCB control critical boiler behaviour; incorrect handling can damage the board, void warranties or create unsafe conditions. A Gas Safe qualified engineer will have the correct spare parts, wiring diagrams and test equipment to diagnose whether the jumper is legitimately required, whether the PCB or wiring harness is faulty, and to safely fit or replace parts.

- If the engineer cannot clear the fault by refitting/replacing the jumper and connectors, further PCB diagnosis or replacement may be required.

Summary: a 119 is a missing or unrecognised jumper on X2 pins 4 and 5. You can do a safe power-off visual check and a reset, but replacing or fitting jumpers, testing PCB circuits and any work inside the boiler should be performed by a qualified Gas Safe engineer.