Using phone to log boiler cycles

My recipe for poor-man's logger on my CI boiler:

-Old phone that was hanging around (Samsung S4)
-Got onto GooglePlay via wifi, downloaded "Sensor Logger" (by Kelvin Choi) (free)
-Used microphone sensor, set to Audio Loudness Only in config (dont want the actual audio, just the levels)
-Put the phone into Developer Mode to be able to disable screen saver while running on power adapter, as it turned off mic.
-Set phone on box near burner, start recording
-I let mine run for 7 hours, and it made 213,000 data points
-Stop recording, export csv file and chart it with something.. I used a web site called Plotly Chart Studio to get this..

In Plotly, you can zoom and scroll and hover to show data sets.

I noted the On/Off time points, converted from the seconds to minutes and found;
- My burner ran 14 times in 7 hours.
- In rounded numbers; it ran 9 times for 5 mins, 3 times for 6 mins, once for 8 and once for 9.

Good example of an oversized conventional boiler for the load ?
It's shoulder season, I look forward to repeating this procedure once the real cold sets in.