This heater control valve is mounted next to the accelerator pedal on Volvo 140/160/240/260 models from 1973 to 1991 and has a thermo-couple-controlled valve.
The original manufacturer discontinued this style of heater control valve altogether. This is a carefully reproduced original design heater control valve. No modifications needed.
Some adjustments may be carried out as desired by rotation of the Phillips head screw, as shown in the picture, to increase or decrease the flow of coolant through the closed valve