Promising signs

On a couple of mornings so far, since fitting of the prototype board, there has been a call for heat. Unfortunately vrDialog does not recognise the new board, so will only collect a small subset of the data that it used to collect. This makes it much harder to monitor the behaviour of the boiler, but yesterday I made manual observations during the 40 minutes or so when there was a call for heat. The signs are good:

There was a continuous burn throughout this period. Thus the boiler was able to sustain a flow temperature at the boiler of 35C or 36C, which I've never seen it do before - typically before it would microfire below about 42C. One slight oddity, though, is that the flow target temperature throughout this period was 28.5C, which doesn't bear any relation the the actual flow temperature (whether at the boiler or at the low loss header, from where a probe is now also wired in to the boiler).

Pending further data, the new board therefore looks as though it may be an improvement over the standard one. All is not quite right, though, since the central heating pump now sometimes stays on all day, even if there has been no heating demand at all, circulating unheated water through the radiators.