BoilerFaultCodesWhat the manual says
Manufacturer manualCheck JP1
From this model's manual
Verified against the Vokera Boiler Rain installation & service manual.
What causes this fault?
This fault occurs when the boiler has been accidentally switched into 'Combustion Analysis' or 'Service' mode. The most common reason is that the control selector knob was turned too far or left in a specific position meant only for engineers to test the gas levels. While in this state, the boiler ignores your thermostat and hot water taps to run at a fixed output for testing purposes.
DIY fix possible
Locate the selector dial on the front control panel.Turn the dial to the 'OFF/RESET' position.Wait five seconds, then turn the dial back to your desired 'Heating and Hot Water' setting.
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 YELLOW LED Solid: 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.