Ideal Logic +18, intermittent fault

[Ed Alexander]

Have an Ideal Logic + 18 with intermittent fault. When on demand the display constantly changes from O to C but burner doesn’t start. Can fix by switching Off then On again, but this only lasts for a day or two. As it’s an intermittent fault I’m reluctant to call out an Engineer. Any ideas?

 

[Deleted member 120897]

Check your motorised valve is activating correctly.

 

[Ed Alexander]

Motorised valve seems ok. But will check again when in fault mode. Currently running with programmer set on On mode (not timed). Have Drayton programmer (Lifestyle) and thermostat (SCR wireless). Boiler display moves from O to C every second when in fault and stays like this.

 

[Ed Alexander]

A bit more info: the fault seems to occur (occassionally) when there is a CH demand. Switching to HW demand only - will normally clear fault (ie burner starts). But goes back to fault mode when CH is demanded, I then need to switch off electrics to clear fault. I'm thinking intermittent Programmer problem so trying with Programmer CH on ON mode (as opposed to Timed). I will update post if this works - and get Programmer changed?

 

[Tomcat]

A bit more info: the fault seems to occur (occassionally) when there is a CH demand. Switching to HW demand only - will normally clear fault (ie burner starts). But goes back to fault mode when CH is demanded, I then need to switch off electrics to clear fault. I'm thinking intermittent Programmer problem so trying with Programmer CH on ON mode (as opposed to Timed). I will update post if this works - and get Programmer changed?

Did you get to the source of this problem? I now have the same uncoded intermittent ignition fault and need to fix it.