Originally Posted by
Andy the Minion
In a previous life I came from the boiler industry and have been used to setting the pump to run constantly in opentherm or otc systems. The HR92 stay open when the boiler is off and my logic is this allows the heat that may have be left standing in a pipe run to be distributed evenly within the house and the water comes down to a nice steady return temperature ready for the next burner on cycle. I have no actual evidence which is better mind, just a gut feeling.