BoilerFaultCodesYour boiler's built-in solar water heating software has been activated, but the solar system hasn't been set up or configured correctly for use.
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: Solar system is not yet in operation. Solar system not yet commissioned
What causes this fault?
This fault occurs because the boiler's internal computer has been told it is connected to a solar thermal system, but it cannot detect the signals it needs to operate it. The most common reason is that the solar function was accidentally switched on during a service or installation without the necessary solar sensors and controls actually being fitted.
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 →Protect yourself from future repair bills
A boiler cover plan would cover faults like 55146 — no call-out fees, no surprises.
Affiliate links — we may earn a commission at no extra cost to you.