Grant Boiler starting up advice

[Matf]

A bit of advice please. I have a Grant vortex eco 26 oil fired boiler with a riello RDB 2.2 burner on a gravity fed system. If it hasn't been used for a day or two, when it tries to fire up the fan starts and a few seconds later you can hear it attempt to fire, this lasts for a second or 2 and it stops firing but the fan continues. A few seconds later it tries again, lasting a fraction longer but then stops, then a few seconds later it tries again. Each attempt lasts a bit longer and the fan goes continually. After anything up to 15 attempts it seems to be working and condensate starts to appear and slightly warm air comes from the flue, this can take 5 minutes or more. Once it has been running it seems to start straight away when heat called for. Is it normal for Grant boilers to start like this? It is less than a year old and the installers have been back a couple of times, the last time "cleaned a thermo-couple" , but when they have tested it and it has "warmed up" it works correctly until it is left off for a day or 2. They are due back again this week but I have little hope of a fix.
Thank you.
Mat
[automerge]1594651312[/automerge]
Brain fail when writing request, Should have read "cleaned a photocell" sorry about that but it wouldn't let me edit.

 

[SJB060685]

This is not normal operation.
Is it a digital control box on this burner? White/clear lockout reset button.
Is it a balanced flue?
Are you saying it fires, flame drops and then relights several times before staying in steady state?

 

[Matf]

This is not normal operation.
Is it a digital control box on this burner? White/clear lockout reset button.
Is it a balanced flue?
Are you saying it fires, flame drops and then relights several times before staying in steady state?

Thanks SJB, No idea if it has a digital control box. Boiler just has on/off Temp and Black reset button. Burner has no controls but a dial showing 4. It is balanced flue and NOT a combi. 2 photos attached. It seems to fire, flame then relight but this going by the noises. As I am a homeowner there is no way I will tinker with it myself, that is for the experts.

 

[SJB060685]

Thanks for responding.

Going by your words of it fires, goes out, then back on several times, rather than going straight to lockout prompts me to consider a few things.
Unfortunately all of them require someone who knows what they're doing and with the right tools to check.
Perhaps the only thing I can get you to check is if there is anything partially obstructing the flue terminal and creating a micro environment.

The situation you're describing is NOT normal operation. Perhaps you should consider trying a different engineer.

 

[SimonG]

It's not been set up properly. As SJB said, different engineer.

 

[Matf]

Thanks for responding.

Going by your words of it fires, goes out, then back on several times, rather than going straight to lockout prompts me to consider a few things.
Unfortunately all of them require someone who knows what they're doing and with the right tools to check.
Perhaps the only thing I can get you to check is if there is anything partially obstructing the flue terminal and creating a micro environment.

The situation you're describing is NOT normal operation. Perhaps you should consider trying a different engineer.

Nothing causing an obstruction, see photos, as it is still under guarantee I will see what the engineer says later in the week and thank you for the advice.
Mat

 

[SJB060685]

If its still under warranty then give Grant a call and it won't cost a thing. I suspect its either a box or cell problem, both are common but there are other possibilities.
Please update us on the outcome