I want to replace my water heater with a Bosch AquaStar 1600H NG (Natural Gas) tankless water heater. Our hot water system has a recirculating pump, and, according to Bosch, the Bosch AquaStar 1600H NG system ignites the burners when water is flowing. My question is, will the recirculating pump keep the burners ignited constantly? It does not seem possible. Are the two systems compatible?

If the water is constantly flowing though the tankless system, it will burn all the time to the point of maintaining the temp. The system turns itself on by the flow and volume though it, many of the tankless systmes have settings or preset so they do not kick in at low volume or flow, why are you using a recirculating pump, what is the purpurse of it in your system ?