What the manual says
Manufacturer manualOverheat (With V9 Primary Control PCB, will display 3 horizontal lines upon reset and not refire until temperature drops below 50oC)
Shared across the Isar range
This code is shared by the boilers in this range, which use the same control board. It may not be printed in this exact variant’s manual.
Engineer required
This is a high severity fault. Stop using the boiler and call a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.
Find a Gas Safe engineer
Search the official register →
Boiler cover options
Avoid the next call-out bill
A cover plan would handle faults like LA/HA: no call-out fees, no surprise bills.
Approved partner
Get a quote →
Domestic Appliance Guard
Unlimited call-outs, 24/7 helpline, no price-hike promise
Affiliate links. We may earn a commission at no extra cost to you.
Related fault codes
All 20 fault codes on the Isar HE
Seeing a different code? Every code this model can display, in one place.