In the OpenTherm page, in the section “Domestic Hot Water generators control”, it is possible to:
...
In the purple box (in the DHW column of the Generators section) to all 1 generators is sent the request to produce DHW at the same time. The OpenTherm DHW is not managed in cascade but in parallel, so all the DHW enabled generators start together (priorities 2 and 3 are not handled).
Warning
G0 is to be used only if you install a DOT display as master that has OpenTherm on board.
...
122. Active Request OT/H+C when request to OpenTherm is ON.
123. Active Request OT/DHW when the request to OpenTherm DHW is ON.
126. Active when at least one OpenTherm generator is in alarm.
127. Active when all OpenTherm generators are in alarm.
PHOTO TBD