BoilerFaultCodesYour solar heating system has stopped circulating fluid properly, likely due to a blockage or trapped air bubbles within the pipes.
This fault should be looked at by a Gas Safe engineer within the next week or two. It may get worse if left.
Technical description: Solar pump jammed or air in system: Air in solar thermal system.
What causes this fault?
This fault occurs when the solar thermal part of your heating system is unable to move fluid between the roof panels and your water cylinder. The most common reason is that air has become trapped in the pipework, creating an 'air lock' that stops the flow, or the solar pump itself has seized up due to a build-up of debris. When the system detects that the fluid isn't moving despite the pump being active, it triggers this error to prevent the panels from overheating.
This fault is more common during the summer months when high solar temperatures can cause the fluid to vaporise, leading to air pockets in the system.
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 Fault 50 — no call-out fees, no surprises.
Affiliate links — we may earn a commission at no extra cost to you.