Temperature Regulation

IHKR1 TEMPERATURE REGULATION







The IHKR1 heater core is divided into left and right halves.
Air discharge temperature is determined by regulating heater core temperatures.
The control module regulates heater core temperatures by controlling coolant flow through the cores.
It does this by operating two solenoid actuated water valves, located at the heater core inlets.
The valves are normally open, and close when they receive ground pulses from the control module. (The valves are powered closed.)

The control module pulses the solenoid valves according to the "Y" factor, which is calculated from the following inputs.
- Left desired temperature
- Right desired temperature
- Interior temperature Left heater core temperature
- Right heater core temperature
- Ambient air temperature Blower knob position

When the left desired temperature knob is rotated fully clockwise (maximum heating), temperature regulation is cancelled and the valves remain 100% open to provide maximum heat output.

Similarly, when the knob is rotated fully counter-clockwise (maximum cooling) the control module keeps the valves closed for maximum cooling.







An electrically powered auxiliary coolant pump, positioned ahead of the solenoid valves, is operated by the control module to assure adequate coolant flow to the heater cores when cabin heating is a priority. The pump capacity is about 250 gallons per hour.