The difficulty with this setup is that in order for the tankless water heater to turn on the burner it needs streaming water. The recirculating pump does not draw enough water to make sure that the burners turn on so for that reason another service needs to be developed to have a hot water setup that consists of a tankless water heating system and a recirculating pump. Hard water will damage a tankless water heating unit. Challenges with a tankless water heating unit is that they need a flow of water to turn the burner on. I can then turn on the hot water and not notice any cooling of the water since the tankless water heater is blending water into the recirculating loop.

Plumbing Care, Inc.