If I were to change from a flat plate EX that heats my domestic water to a sidearm setup, can I run the water only part of the time and have enough heat? I currently have to run my boiler water continuously, and wish to only circulate that same water only when my house air furnace kicks on. The whole idea is that it may save some heat at my storage tanks. Heres the catch- the storage is 80 feet away. my furnace fan tends to kick on for 5-10 min, off for 15-20 unless below zero.