PCB 38 HW light flashing High

Ideal PCB 38 HW light flashing Fault Code

Also written as PCB38HWLIGHTFLASHING — same fault.

The Ideal PCB 38 HW light flashing fault code means: your boiler's hot water sensor is struggling to communicate with the main control board, meaning the system cannot accurately monitor the water temperature.. It appears on 1 Ideal model in our database.

Call an engineer soon

Book a Gas Safe engineer within 24 to 48 hours. Your boiler may be unsafe or could break down completely if left.

Technical description: This indicates an 'open circuit' or 'short circuit' HW sensor or lead.

What causes the Ideal PCB 38 HW light flashing fault?

This fault occurs when the boiler's internal computer loses track of the hot water temperature because the sensor has failed or its wiring has become damaged. The most common reason is that the sensor has physically degraded over time or a loose connection has developed, preventing the boiler from safely heating your water.

Typical repair cost £120-190 (including labour)

Engineer required

This fault requires a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.

Find a Gas Safe engineer

Search the official register for a qualified engineer in your area.

Gas Safe Register →

Ideal models that show the PCB 38 HW light flashing fault code

Click a model for the full fault code list and model-specific repair notes.

Source

Ideal PCB 38 HW light flashing fault code information on this page is sourced and cross-checked against the official Ideal service / installation manuals for each affected model.

Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed 27 April 2026