BoilerFaultCodesWhat the manual says
Manufacturer manualdomestic hot water cycling mode active
What causes this fault?
This status occurs when the boiler's keep-hot function is activated to maintain a small reservoir of warm water inside the heat exchanger. It is a normal operation designed to reduce the time you have to wait for hot water to reach your taps. The boiler will fire up briefly even when you haven't turned on a tap to keep this internal temperature topped up.
DIY fix possible
Check if the 'Eco' mode is turned off; if off, the boiler will fire periodically to keep the heat exchanger warm.Press the 'Eco' button if you wish to disable this pre-heat feature and save energy.Observe the display; the S.20 code should disappear once the pre-heat temperature is reached.
Avoid the next call-out bill
A cover plan would handle faults like S.20: no call-out fees, no surprise bills.
Affiliate links. We may earn a commission at no extra cost to you.