corroded Heating, Ventilation and A/C switch leads to oil furnace not turning on

The seasons changed truly fast this year.

It went to 90 degree nights to 40 degree evenings over the course of 24 hours.

When I went to change my temperature control from A/C to heat, it did not change. The air-conditioner stayed on, then cold air continue to pour out of the vents & I could hear the compressor kicking on just the same as I did before. Clearly, it was time to call out the professionals. I did not know who to call or where to start. I did not know if I should call the furnace or the A/C repairman. I looked it up, & I discover that they are all a single & the same & they go under the title Heating, Ventilation and A/C repair. An Heating, Ventilation and A/C repairman was able to come out the truly next afternoon & he explained the situation. It seems that there is an internal switch inside my heating & air conditioner that tells the system to turn on the heat or to turn on the A/C. It all depends on what I set the temperature control to. The problem is, that the switch was broken inside my system. This resulted in my system being stuck with the A/C on, regardless of my temperature control settings, and because my Heating, Ventilation and A/C system is so old, the specialist had to order the part. I assume I will have to make do with a space furnace for a few evenings. I just hope it does not get entirely chilly before the switch arrives & he is able to respectfully repair my Heating, Ventilation and A/C unit.

Air conditioning technician