I have a saunier Duval combitek f23e boiler. My boiler fires up when i turn on the tap or start the heating but it doesn't know when to switch off the flame and keeps heating until it locks out. I have changed the thermistor and fitted a recondition pcb which worked for a few days and then the old problem returned. Can anyone help please?
One more thing to note, is that the boiler sounds like an aircraft jet engine winding down when you open the hot water tap.
One more thing to note, is that the boiler sounds like an aircraft jet engine winding down when you open the hot water tap.
