Error 2 pulses

Safety first:

- If you are not confident working near gas or electrical equipment, stop and call a Gas Safe registered engineer.

- Before removing any covers isolate the boiler electrical supply at the external switch or consumer unit and, if you can safely do so, turn off the gas supply. Do not work on the gas pipe or burner yourself.

- Keep children and pets away from the boiler while you inspect it.

Initial checks a homeowner can do (no tools or limited access):

1. Note exactly what the display is showing (2 pulses) and whether any other symbols or messages appear. Take a photo for reference.

2. Check the boiler is powered (front light on) and that room thermostat or programmer is calling for heat/hot water. If there is no demand the boiler may be in standby.

3. Locate the user reset for your model: some Greenstar boilers have a reset button or a reset position on the temperature knob. Try a reset by pressing the reset button for 3 seconds or by turning the dial to the reset point and holding for 3 seconds, then return to normal setting. Wait a few minutes to see if normal operation resumes.

4. Check the boiler instructions or the label inside the front cover to find the service mode switch location. On many Greenstar Ri models the service mode switch is accessible behind a small panel or on the control PCB and will have positions labelled MIN, MAX or similar. If you find it, confirm it is set to MIN (minimum) as the error message requests.

Specific diagnostic and fix steps you can attempt safely:

1. With the boiler powered and calling for heat, observe whether the 2-pulse symbol clears when the service mode switch is in MIN. If it clears, allow the boiler up to 15 minutes to return to normal operation. Some modes (siphon fill, air purge, minimum/maximum service) can run for up to 15 minutes as part of safety/commissioning routines.

2. If the switch was already in MIN or you moved it to MIN and the error remains after 15–30 minutes, try a controlled reset (as above) once more and watch the display while the boiler attempts to start.

3. If the error returns immediately or does not clear, do not attempt to probe or change wiring. A persistent error can indicate a faulty service mode switch (mechanical failure), a wiring/connecter issue between the switch and the control board, or a control board fault.

4. Record the boiler model, serial number, the exact error (2 pulses), and the steps you have tried. Photograph the service mode switch position and any labels inside the cover. This information helps the engineer diagnose quickly.

When to call a professional:

- Call a Gas Safe registered engineer if the 2-pulse indication does not clear after setting the switch to MIN and doing a reset, or if you cannot access or confidently identify the service mode switch. Also call an engineer if the boiler will not provide heat/hot water, if there are other fault codes, or if you detect gas smells or other unsafe signs.

- Do not attempt internal electrical or gas component repairs yourself. A qualified engineer will check the service switch, its wiring and connectors, and the control board, and will carry out safe repairs or replacements as required.

Extra tips for the engineer visit:

- Have the boiler model and serial number and any photos ready.

- Note how long the indicator was present and what you tried (reset, moved switch to MIN, waited 15–30 minutes). This speeds diagnosis.

If at any time you smell gas or suspect a leak, leave the property immediately and call the gas emergency number for your country before contacting an engineer.