Valving the boiler outlet is not the best idea, the flash boiler lets you superheat the steam to 300+ degrees if desired so the coil temperature can be raised by increasing the burner flame. The cheapest approach to water measurement has been to fill an unheated container with either all water for batch, or refill after strike water. The HLT becomes redundant as the boiler will deliver any temperature water on demand, no need to store hot water. Saving the condensate is good from a energy conservation aspect but is not necessary for operation as boiler capacity should be sufficient for low flow sparge heating from 50 degree inlet water. Normal boiler/water system operation is all water for 6 gallon batch is placed in water tank and then a pump moves water through boiler in strike heating mode until all strike water is in MLT. Left over water is used for steam stepping and then sparge water. A float and rod arraingement was used on the old system and pressure sensor level measurement was used on the new systemThe "Park" model sureflo pump works if a return line and needle valve are installed on the pump discharge line to keep pump running continously. With the lower back pressure the pump motor has not overheated even when run 45 minutes for sparge water heating.