__________________________________________
View my fuel log 2015 Mirage ES 1.2 automatic: 40.5 mpg (US) ... 17.2 km/L ... 5.8 L/100 km ... 48.6 mpg (Imp)
Thanks for the reply. My home AC doesn't seem to do that, or at least it does it on much, much longer cycles. Like every 10-15 minutes or so. But every 30 seconds is normal on the Mirage? It did this consistently for 40 minutes idling in the shade at 7:30 AM this morning.
From what I have read elsewhere this is called short cycling and is bad, but if the Mirage is simply designed to work this way then I guess it's not an issue. Would it be more helpful if I posted a video on YouTube?
You do make a point about the humidity, it is extremely humid here so I imagine a lot of water is pooling up. Does this mean my car has a humidity sensor? Sorry if that's a dumb question.
Get a meat thermometer (or the like). Set the AC to 61, put the thermometer in the center dash vent, and set the controls so air just blows through those vents. Crank the blower speed up about halfway.
If the thermometer reads 40 or so degrees when the compressor is running, then your AC is working properly. If it does not get down to this approximate temperature and is still 'short cycling', then you may be low on refrigerant.
The car's system does not have a sensor for humidity. But it should have a sensor for the temperature of the evaporator. If it senses the evaporator is freezing, it cycles the compressor off. This has to be done because all of the humidity in the air flowing through the system is condensed out and becomes water. Normally, this water is removed through a little tube in the bottom of the heater box that exits underneath the vehicle. However, if this moisture turns to ICE then it blocks airflow through the evaporator and reduces the effectiveness of the system.
Setting the AC to 61 degrees on a humid 105 degree day may cause this to happen. Also, make sure you are using the 'Recirc' setting on the controls. This keeps the car re-cycling already-cooled air from inside the car instead of sucking hot, humid fresh air from outside and trying to cool it.
A good rule of thumb, for me anyway, is to set the AC about 25 degrees cooler than the outside temp. Any more than that can be asking too much.
ganzfeld (09-13-2016)
I don't have a thermometer but I can pick one up. In the meantime I just took it out again and tested it. It's 88f outside so I put the internal temperature on 76 and set it on auto. With the blower on around mid or slightly above the fans of the side vents got so cold that they got slightly moist. It definitely seemed like it was cooling and the compressor did not shut off.
In fact, the compressor never shut off until I set the blower to the minimum setting. Then, it began the cycling of shutting on and off exactly every 17 seconds (I timed it with my phone.)
If I set the blower back up even a tick the compressor would engage and remain on for several minutes.
Perhaps I am obsessing over nothing; I'll try and get a hold of a thermometer and see if it's actually putting out 40f.
I wonder if any vehicles are using 2-stage scroll compressors?
__________________________________________
View my fuel log 2015 Mirage ES 1.2 manual: 49.6 mpg (US) ... 21.1 km/L ... 4.7 L/100 km ... 59.5 mpg (Imp)
MightyMirageMpg (09-04-2016)
So I did get a thermometer: when idling in the shade (but an ambient temperature of 91f) it would only get down to around 55. However, when on the road, it got down to 38-40f! Very cold. So it seems it just can't keep up with the outside temperature in this combination of heat/humidity? Would you say it's safe to say that if it can get down to below 40 there isn't a low freon issue? Thank you again for your reply.
Most cars in that high of temp idling will blow a little warmer air until you start moving. When moving, you'll get more air movement across the condenser and cooler air from the a/c. Keep in mind, the temp drop that an a/c should be able to create is about 40 degrees difference between ambient and interior temp. High humidity could decrease this drop. I'd say your car is fine.
(blank signature)
ganzfeld (09-13-2016)
__________________________________________
View my fuel log 2015 Mirage ES 1.2 manual: 49.6 mpg (US) ... 21.1 km/L ... 4.7 L/100 km ... 59.5 mpg (Imp)