Air Conditioning - AC Slow to Cool - Spray Water on Heat Pump?

I keep my house at 85* while I'm at work, outside temperature can approach 100*. When I came home from work Thursday, it took over 5 hours to get the house cooled off to 75* and I'm not even sure that it would have cooled off had the outside temp not gone down as the sun went down.

I cleaned the coils and had someone check the refrigerant and it was at normal levels. I was told that the unit just can't dissipate the heat into the air when its 90*-100* outside. I think what I want to do is rig something up to spray water on the heat pump when it runs as this caused the head pressure to drop significantly. Are there off the shelf systems available that do this? If not, I'll build something out of some PVC and spray nozzles. I'd want it to only spray water when the unit is running, I can handle all of the electronics if I have to build it myself.

Id first say don't set the T-stat to 85. Maybe 80 max and that is still to high! Just a couple of degrees is best. 5 hours to drop 10 degrees sounds great with the high temps. Water being sprayed on the condenser is a very short term solution because it will eat the fins. Like said I just lower the set point and let it go!

I agree with airman 100%.

For sure dont try and spray water on the hot condenser coil. You will get a build of the lime and calaium on the coil very fast and end up . Buying a new condenser

A/C are not made to recover quick like a furnace would when you have a large temp change.

A/C are best to "set it and forget it". You can bring it up a couple of degrees if you really need to save something.

Set the tstat to 75 degrees and keep it there. Let it run a few days and report back.

Programable stats work great in commercial apps but, (I think) residential is best served by setting one temp and leaving it there 24/7.

Ok guys, you've all turned me off from the spraying of the water thing. It might be OK if I had a good water filter in place, but I don't want the hassle of changing the filter every few days. It holds the temperature at 75 just fine over the weekend, and it was at least as hot these two days as it was this past Thursday.

I'm gonna get me a dehumidifier and run it all day with the day temp set to 85 again tomorrow. If it doesn't improve the cooling time I'll set the day temp to 80 and see if thats acceptable. But the dehumidifier should help I think.

A dehumidifier only keep the air dry, not cool.... But, you may find out that your home is dryer, may lead you keeping your temp set point higher.

The running of a dehumidifier is going to heat up the house even more.

As others have said, set your thermostat at a temperature at which you will be comfortable & leave it alone.

But an AC is more efficient at lower humidities. I realize that it will generate about 300 watts of heat and it'll run nearly 24/7 but the AC should benefit greatly from it. I live on the MS coast, humidity is pretty extreme.

Don't mean to be argumentative, and I do greatly appreciate the help. You guys have already saved my compressor. If this fails, then I'll be setting my thermostat to 75 and leaving it.

Please explain how an A/C is "more efficient at lower humidities".

My father helped a friend upgrade a geothermal unit a few months ago. The manual described the air conditioning process as being very slow in a high humidity environment. The AC acts a dehumidifier drawing the moisture from the air as it cools. As the humidity gets lower, the AC becomes more effective and can change the temperature more rapidly. I'm no expert, maybe I'm wrong. Maybe that AC company was also in the dehumidifier business.

I live on the coast of Mississippi, a mile north of the Gulf. Humidity outside is often in the 90% range, right now its 98%. I suspect that it'll be about 94% at lunch time.

you need to set the stat on one temp and leave it.

When your a/c comes on the first job (at hardest) job it has is to remove moisture from the air, this is called Latent Heat.

As the moisture content (humidity) is lowered the a/c can start working on the easier job of lowering the temp in the house. This is called sensable (SP) because it is the temp you actualy feel.

Your a/c is a dehumidifier, adding another will only make your a/c's easy job harder.

Pick a temp and stick with it.

If you think its all in what the humidity is in the home you can do like our V/S blowers do. Drop or slow down the blower speed one step. See how it does. It will pull a lot more humidity out for you.

Yes the dry air from the dehumidifier will make the air feel cooler, but how much does it cost to run a dehumidifier? The dehumidifier will also introduce more heat into the house, so you've saved nothing. Infact added more costs.
I'll have to agree with previous responders set it at 75 degrees and forget it.