In article , Set Square wrote:
Andy, do you happen to know what the earliest start time is for a CM67? I
had a feeling that it would start up to 2 hours before the target time - but
when answering a call of nature early this morning, I found that the
radiators were hot two and a half hours before the target time - so it
must have started even earlier. Is this normal?

This is exactly what I experienced which is why I turned optimisation off.

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