Boiler displays A34; may be associated with low mains voltage or power supply issues.

This repair may involve working with high voltage components or water connections. Always unplug the appliance before removing any panels.

If you are not confident in your ability to perform this repair safely, we strongly recommend contacting a professional technician.

Possible Causes

Mains voltage below specification, Loose electrical connections, Faulty internal power supply on PCB, External power issues

Safety first: Electrical work must be carried out by a competent person. Isolate power before opening any covers.

Check other appliances: If lights dim or other appliances behave oddly, contact an electrician or your power supplier.
Verify fused spur: Ensure the boiler's fused spur is switched on and the fuse is intact (typically 3A).
Engineer checks:
- Measure mains voltage at the boiler terminals.
- Inspect internal wiring and terminal blocks for loose connections.
- Test the PCB's low-voltage power supply section; replace PCB if defective.

Medium 3/5

Main PCB (Power Supply Section)

Check Price on Amazon

We may earn a commission from links on this page.