Hotstart SB122100-000 Coolant Tank Heater (Obsolete) – No Thermostat The Hotstart SB122100-000 is a 2.25kW, 120V coolant tank heater designed to maintain engine coolant temperature for reliable engine starting and reduced wear during cold-weather operation. This heater was commonly used on standby generators, diesel engines, and other industrial equipment. No thermostat. Obsolete Notice: The SB122100-000 has been discontinued by the manufacturer and is no longer available for purchase due to low demand. Original Configuration: The SB122100-000 was supplied without a thermostat, providing continuous heating whenever power was applied. Recommended Replacement: The recommended replacement is the Hotstart SB122110-200, which features a built-in thermostat with an operating temperature range of 100°F to 120°F (38°C to 49°C). The thermostat helps regulate coolant temperature, reduce unnecessary power consumption, and extend heater service life. Message us today to confirm availability and shipping time.