still waiting on reply woman with two kids has no water or heating kids under 5 landlord cant come out till monday make & model is a heatline premix boiler

m.clyne, October 2010

Code f4 for mean it has flame sensor is defective It may also be defective sensor at discharge filling trap. Remove the white cable from the sensor, reset boiler and fire up boiler. I find heatline after sale service is very poor

Rio gas tec, October 2011

Search on here in the box on the top right - use the word ionisation (no letter R).

From what I can see its something to do with the ignition spark (might not be though) and it may need a Gas Safe Engineer to call - not the landlord who is forbidden by law to repair his own boiler I believe.

Peccavi, October 2010