Interesting (to me) temperature graph

I have been working to improve my 34 year old Weil McLain 2 pipe steam boiler in a 100 year old brick house in MI.

Motivated by some YouTube videos including @ethicalpaul and other I was determined to confirm that I didn’t have any surging and was convinced I could do that by monitoring temp since I was (correctly I think) advised to not mess with the NBP.

The most interesting thing about this graph to me is that the equalizer temp rises a bit during the burn cycle but does a much bigger increase after the burn cycle ends. My opinion is that after the burn cycle ends, there is not enough energy to keep steam going to the main and radiators so it falls short and drops into the equalizer (short circuit).

This is not really an issue as that keeps the boiler warm and not as much energy is spent on the next burn cycle. It does illustrate a bit of the cost of short cycling though.

I think my main stays hot much longer than shown, the main temp is from the side of the vent which is cooled by the inrush of air after the burn cycle. Will prove this with another run with the probe on the main pipe instead of the vent.