Low
4 green flashes on Baxi Suprima 70

Your boiler is having a temporary 'conversation' issue between its internal parts and should fix itself momentarily without you needing to do anything.

Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed

Monitor it

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

Communication error between printed circuit board (PCB) and control. Temporary error, will self reset.

DIY fix possible

Wait for the boiler to automatically reset itselfIf the flashing continues for more than 10 minutes, turn the control knob to reset and back to the desired temperatureEnsure the power supply to the boiler is stable and not being interrupted

Find a Gas Safe engineer
Search the official register →

Related fault codes

3 green flashesView →

Related guides you might find useful

Yellow or orange flame — CO safety

Safety-critical — turn off, read this.

Read →

Is boiler cover worth it?

Break-even maths on monthly cover.

Read →

When to replace your boiler

7 signs repair isn't worth it anymore.

Read →