I have the above quite old but regularly serviced oil boiler
Over the last couple of weeks it has sometimes (but not always) made a sort of 'pinking' sound for a minute or two when starting up from cold in the morning or when fired up during the night by the frost stat.
Otherwise its fine. Any ideas what could be the cause?
Thanks
Over the last couple of weeks it has sometimes (but not always) made a sort of 'pinking' sound for a minute or two when starting up from cold in the morning or when fired up during the night by the frost stat.
Otherwise its fine. Any ideas what could be the cause?
Thanks