I'm in the process of installing a Tarm Solo 40 with storage as my primary source of heat. My present oil fired boiler is on it's way out and I'm going to replace it. I've been looking into oil boilers and have been wondering if oil boilers would have any problems with thermal shock of cold water returning as the Tarm can experience. Should I look into a mixing valve for the oil boiler as I did on the Tarm? It is just a backup, for when I'm not around to keep the home fire burning.