System Boiler pump runs but no burner

[Bargain Bucket]

Will do. Many thanks.

 

[Bargain Bucket]

Morning all. I'm not sure what to make of the status codes. I go to D99 and all I'm shown in the display is the number 1 with "nnn" under it. I can change the 1 to a 2 by pressing the + button and the "nnn" is replaced by "---". Similarly all the way up to 10 whereupon it loops back to 1 and "nnn". What am I missing here?

 

[Bargain Bucket]

Ignore my last message. I was being daft.

Results of monitoring when the HW schedule started today.

• Fired up OK (S3 then S4).
• D40 went up to to the pre-set temp of 75 and modulated around that for short while. D41 was about 56
• D40 then exceeded the pre-set temp of 75 (rapidly climbed to hit 78).
• Burner shut off with S6 then S7
• After a few minutes the boiler fired up again and the pattern repeats.

 

[Bargain Bucket]

Same results with the CH schedule although it took much longer to reach the 78 (might be 77) that it decided to shutdown upon reaching rather than modulating back (it did modulate for a while around 75 before finally overshooting to 77/78 and shutting down to S7).

 

[ScottishGasMan]

Sounds perfectly normal to be honest. they can only modulate back so far, once set temp is reached it will be on virtually its lowest available rate, but as the flow temp continued to increase (because the boiler cant put any less power in) it will shut down and keep circulating for a while then restart. Essentially that is how a boiler should work.

The only issue/question is how long it takes before it restarts. Which should be less than 10 minutes