I have an old air conditioner that uses non electronic temperature control.
It exhibits a large hysterisis. In other words, there is a large temperature
difference between when the pump kicks in, and when it turns off. This means
the air con won't cycle off until it's way too cold, and if I adjust the
thermostat to fix this, then it won't cycle on until it's way too hot.
Is there a commercial product to retrofit this type of thermostat with an
electronic one? This could be done by wrapping a heating coil on the
temperature probe of the old thermostat. Then when it is desirable to cycle
on the air cond, just heat the coil a little, and when it is desirable to
cycle off the air cond, just turn off the heating coil.