Turning the heating off immediately forces all the heat demand figures in the system summary page to 0% and turns off the boiler relay immediately, rather than the usual several minute delay where set point changes are sent to HR92's, HR92's close and send back zero heat demands.
It seems that if the set points of zones are set more than a certain amount below the current measured temperature (I don't know how much yet, more testing needed) then the heat demand for the zone is internally forced to 0% in the controller even before the HR92 sends an updated heat demand.
This solves a few problems:
1) Slow "heating off" action. Now pressing heating off works immediately causing the relay to go off and stay off even before HR92's react. (Lot's of people ask why heating off is so slow or why the boiler seems to cycle on again after heating off is applied)
2) Solves the problem where a comms issue causes one HR92 not to report back a zero heat demand causing the boiler to run on for another 20 minutes or so. (I see that occasionally)
3) Solves the issue of people manually turning up HR92's in heating off mode (or away mode for that matter) - previously this would not appear on the controller but the boiler would come on and heat the room anyway! Not anymore. Parents will love this change...
