Value of misters for your central air

Brian Diehl · July 31, 2006, 06:45:38 AM

Some of you may remember where I posted a question about why my basement A/C was continueing to draw additional amps as it ran. It would start up at 13-15 amps and then continue to increase up to 20 amps. The concensus of the board was that I had to improve the air flow across the condensor. My project this weekend was to do that. I ended up cleaning up the air flow dramatically and improved the performance of the A/C. I was testing with one compressor on in our 95+ degree heat and the max current draw of the single compressor was 15 amps. I'm very happy to report the improving air flow to the condensor was a success. Thanks for your advice!

In the past I had read how someone put misters on their A/C on the condensor. I decided to give it a try and see what would happen. I put two adjustable flow misters from Menards on the front of my condensor. I only have about 6" of room and by the time I got the misters installed they were about 5" from the condensor. This meant that the two mister heads only covered about 20% of the condensor. Still, I proceeded to get it all installed and tested and found that with the misters running the A/C would draw 13 amps instead of the 15 amps. I'm very impressed how such a little amount of water could make such a big difference.

I have adjustable flow misters that are rated at 0-8 gph at 25psi. My water pump averages about 30 - 35 psi and I had the misters set almost off. I was probably flowing about 1-2 gph total during my testing. I think if I installed two more misters to get more of the condensor under mist it would increase the efficiency even more. I haven't decided if I'm going to do that yet. I still need to hook up the solenoid valve so I can turn the misters on and off without manually opening the valve on the water manifold. I'm going to try and ty in the mister circuit with the compressor circuit so that if the compressors are off the misters turn off as well.

Len Silva · July 31, 2006, 07:20:44 AM

Brian,

I did exactly that on my home AC system some years ago, using straight city water. In a very short time there was a significant calcium build up on the condenser. I tried cleaning it up with Lime-a-way and ultimately ruined the unit. The current reduction and lower outlet temps were amazing but not worth the ultimate cost.

Len

Brian Diehl · July 31, 2006, 07:29:27 AM

Good point... I'll need to keep an eye on my condensor and see how it does. I don't intend to use the misters all the time, just on days that are in the upper 90s like today -- supposed to be over 100 today here in central Minnesota!

Nick Badame Refrig/ACC · July 31, 2006, 08:31:28 AM

Hi Brian,

I'm glad that you improved your air flo, I remember posting about it.

The water is a great way to cool the A/C's, We do it all the time in heat waves.

Just be careful that the water is Not getting in the Condencer fan motor, You can easily burn out the motor!!

Good Job!
Nick-

Len Silva · July 31, 2006, 10:40:48 AM

Brian,

I would also suggest that if you have your misters controlled the the compressor circuit, you unclude some kind of time delay so that the water continuse to run for a minute or two after the compressor shuts down. This will cool down the condensor so the water doesn't boil off as fast, perhaps leaving fewer deposits.
If you are using a water tank, then distilled water might help.

Len

DrivingMissLazy · July 31, 2006, 10:47:18 AM

My experience with misters is that they should not mist on the radiator/condenser directly. I had mine turned out so that the mist cooled the air before it hit the radiator. Therefore no buildup of crud. In this mode of operation the misters would reduce the engine temperature 20 degrees in less than five minutes. In the many years I used the misters, I never had any buildup on the radiator.

I am assuming that the radiator and condenser are operating in similiar fashion to cool a liquid.
Richard

Brian Diehl · July 31, 2006, 12:23:59 PM

Interestingly enough I don't have enough room to setup the misters to not directly precipitate on the condensor. I also don't have any problem with the water evaporating because the condensor just doesn't get that hot. In fact, without the misters the condensor coil surface is just barely "hot" and with the misters on the condensor surface away from the mister is just luke warm to the touch.