The Heating Unit consists of a heating unit with a maximum power of 1.2 kW (1.14 Btu/s) that is controlled manually using a built-in adjustment knob or externally using 0-5 V or 4-20 mA signals. It has two temperature measurement ports (inlet/outlet).

The Heating Unit is protected using two high-temperature cut-out switches: one with an automatic reset and one with a manual reset. The Heating Unit is also protected using a current breaker.