Quote:
Originally Posted by Atlblkz06 INCORRECT!
The heater core is "off by default".
When in "max cool" - the A/C compressor is on and you get cold air.
When the knob is moved to the right - the A/C compressor cycles on and off based on a % and when the A/C is off you're getting air from outside or inside that is NOT temperature treated. The heater core is not functional at this point.
When the temperature knob is moved to ~ the 50% position, heat from the heater core is slowly mixed in. In most cars this is an infinitely variable adjustment.
In short - your heater core is sealed off until the temperature knob crosses the ~50% position. If set to the higher 50%, the A/C can still be turned "on" via the switch but I doubt it does anything - anyone know? |
I had created this thread as a newbie in order to get help. But I ended up facing more opposition and criticism like this one, though a few people really helped. I think it was because of may different (and valid) reasons-
1. When I created the thread, I had almost no idea as to how exactly heating part works and how the temperature control works. Moreover, I had probably described the problem in the most boring/irritating fashion
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2. Many other people who replied didn't have better understanding than mine.
3. There seems to be differences in terms of how heating is achieved in old versus new cars, Indian versus some other parts of the world. I have come across three kinds of heating mechanism being talked about- Electrical heating, Heating using warmed up engine coolant and Other fuel based heating without depending upon engine warm up. I know for sure that my car uses engine heating (Confirmed in service manual as well). I also believe that this applies to majority of other Indian cars. In this case, there is no question of heater being turned ON or OFF because it is ready for use all the time, once engine warms up. Only how much hot air gets used/mixed in airflow is something that is controlled.
4. Similarly there seems to be differences in the way temperature control is achieved. In my case, it is done by using air flow control to varying the amount of air being passed through heater core. It is like this- all the air passes through the cooling coil (A/C), there is no control on it. So, depending upon whether you have switched the A/C ON or OFF, all air gets cooled. A part of this cooled air is passed through heater core depending upon the position of temp control knob. When it is at coolest position, heater is bypassed completely, when it is at the hottest position, all the air passes through heater, and when it is in the middle, only 50% of cooled air passes through the heater while rest 50% bypasses it. A/C is not controlled at all, it has the thermostat only to cut it off when it reaches freezing temperature, irrespective of the temp control knob's setting.
Hot air starts mixing as soon as you move away from coolest position, and I had posted another proof for this (a leaflet from Maruti). Again, I believe this is common for Indian cars.
With other heating mechanisms mentioned, there may be a different scheme to implement temperature control. Like what you said, they may be "directly" controlling A/C duty cycle (% time ON) and there may be heater control as well. Also it seems older cars didn't allow A/C to be ON while using heater, but that doesn't seem to be common these days. I am not so sure about methods other than in my car.
All that said, I have done what I wanted to and it is working exactly as per expectations keeping me satisfied. BTW, your comments were based on which car?