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Old 5th September 2009, 14:41   #16
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AFAIK If the blower switch is off, the AC and compressor also gets automatically off.
You may confirm this by the boost in the pickup of your car.
I never switch off the AC switch, it only blower speed/switch which does the job.
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Old 6th September 2009, 19:30   #17
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Quote:
Originally Posted by aaggoswami View Post
This also prevents something called Icing. I dont know about latest systems, but in earlier systems icing was a problem.
This problem is not very common in the newer cars so long as the thermostat is working correctly ensuring that the compressor cut out happens at the set temperature level.
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Old 6th September 2009, 20:04   #18
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When the blower switch is turned off the compressor also cuts off. There an interlock to ensure this.
It matters little which switch you turn the AC off with. But as Parm has said, keeping the blower running for a while helps prevent fungal growth and bad odours.
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Old 6th September 2009, 20:41   #19
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Quote:
Originally Posted by anupmathur View Post
When the blower switch is turned off the compressor also cuts off. There an interlock to ensure this.
It matters little which switch you turn the AC off with. But as Parm has said, keeping the blower running for a while helps prevent fungal growth and bad odours.
Not always Anupji. In FIATs even if the blower is at 0 position with the A/C switch in on position, the blower still keeps running.

I would suggest rather than continuously switching on and off the A/C, control the temp in the car cabin through the thermostat that's been provided.
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Old 6th September 2009, 21:39   #20
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Quote:
Originally Posted by MileCruncher View Post
Not always Anupji. In FIATs even if the blower is at 0 position with the A/C switch in on position, the blower still keeps running.

I would suggest rather than continuously switching on and off the A/C, control the temp in the car cabin through the thermostat that's been provided.
Yes, it was like this in my previous Fiat Uno.
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Old 6th September 2009, 22:28   #21
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Quote:
Originally Posted by MileCruncher View Post
Not always Anupji. In FIATs even if the blower is at 0 position with the A/C switch in on position, the blower still keeps running.

I would suggest rather than continuously switching on and off the A/C, control the temp in the car cabin through the thermostat that's been provided.
Alot of Europeans cars are like this.
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Old 28th June 2011, 15:23   #22
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Default Re: AC Switch OFF or Blower Switch OFF

Adjusting the thermostat nearer to the 'Red' portion results in heat being drawn from the engine coolant into the cabin. I guess this does NOT result in less use of compressor, so the petrol consumption would be the same as when the a/c is in full mode.
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Old 28th June 2011, 17:25   #23
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Default Re: AC Switch OFF or Blower Switch OFF

Quote:
Originally Posted by jinojohnt View Post
Adjusting the thermostat nearer to the 'Red' portion results in heat being drawn from the engine coolant into the cabin. I guess this does NOT result in less use of compressor, so the petrol consumption would be the same as when the a/c is in full mode.
I agree with Jinojohn. Heres my understanding or belief.

In cars with manual HVAC systems, the thermostat controls only the temperature of the air blown by mixing heat from car's coolant, it does not track the cabin temperature. So even if the temp is not set at the coldest, the compressor will continuously run and hot air will get mixed to increase the temp of the air, which is not exactly the most efficient way to do it.

In car with automatic climate control my understanding is that cabin temperature is tracked and compressor is shut down when desired temp is achieved.

My normal practice is to switch off the AC if it gets too cold but let the blower run to keep getting circulation, this should help efficiency as well vs changing the temperature setting. Also since i got a ford Ikon, i am anyways scared to touch the temp in the fear of the heater valve getting stuck
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Old 28th June 2011, 18:08   #24
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Default Re: AC Switch OFF or Blower Switch OFF

^^^ That's correct.

Air conditioning (AC) essentially means changing the characteristics of ambient air to desired one. Cooling is of course the more commonly made change. In addition AC includes changing the humidity, pressure (used in data centers) etc

The advantage of running the AC with temperature controlled through the selector is the removal of moisture from the cabin which is most required in rainy season.
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Old 29th June 2011, 12:02   #25
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Default Re: AC Switch OFF or Blower Switch OFF

Thermostat is provided to prevent Icing in the evaporator. For palio its set to 2.5 C grill temperature. The temperature knob is not a thermostat setting rather its a mixture control between Engine coolant and refrigerant to get desired temperature. So turning of the A/C will actually save fuel. For ACC setting the temp between 22~24C will save some fuel.

Regards,
Vijay
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