Firefighters used a thermal image camera to identify the cause of smoke which filled part of a house in Sandygate, Keighley, early this morning.
Crews discovered that a central heating pump had overheated, melting a rubber mounting block.
They disconnected the power supply to the pump but no other action was required.
Firefighters from Keighley and Bingley were called out to the incident, at 2.30am.
The occupants had been alerted by a smoke alarm and safely evacuated the property.