Valliant ecoTEC Plus 428 - Anti Cycling

[heating12numpty12]

I have just tried 14KW on d0 and it made no difference to the boiler going into anti-cycling.

From a previous comment made, these boilers require 20KW in their purging state, and this is not modified by d0.

 

[heating12numpty12]

that chart is up there which a chocolate kettle....

Sorry but I don't understand the comment.

What's the story between the right side of the pump overrun comment and the left side of the 2nd burn comment?

So are your referring to the failing temperature following the Pump Overrun and prior to the 2nd burn. If so, it's just the temperature of the water in the bypass circuit slowly reducing.

What is the S code of the boiler.

How do I find the S code? What is the S Code?

 

[wannocks]

Sounds like the output is too big and the flow temp is too low. The boiler will run at approx 3/4 of full output to establish a stable flame (regardless of D0). If the flow temp goes above the demand temp during this period it will shut down and go into pump overrun then anti cycling.