BoilerFaultCodesYour thermostat has told the boiler to stay switched off because your home has reached the requested temperature or a timer has kicked in.
This is a minor fault. Keep an eye on it and mention it at your next annual boiler service. Reset the boiler and see if it clears.
Technical description: Room thermostat blocks heating operation (terminal 3’-4’ open)
What causes this fault?
This status code appears when the electrical connection between the boiler and your thermostat is broken, signalizing that no heat is currently needed. It most commonly occurs because your home has reached the desired temperature or your heating schedule has timed out. In some cases, it can be triggered by flat batteries in a wireless thermostat or a loose wiring connection at the control box.
DIY fix possible
Check if your room thermostat is set lower than the current room temperature.Replace the batteries in your wireless thermostat or programmer.Ensure your heating timer or app is set to an 'On' period.
Find a Gas Safe engineer
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A boiler cover plan would cover faults like S.30 — no call-out fees, no surprises.
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