Misting Systems
By: Amanda Campbell
Updated: August 30, 2010
If you’re looking for a way to beat the summer heat, a misting system might be the answer for you. By installing an outdoor misting system on your patio you can reduce the temperature by as much as 20°.
STEPS FOR INSTALLATION
How does it work? It's a really simple process. Misting systems provide outdoor cooling through evaporation, called evaporative cooling or thermal dynamics. Water requires energy to evaporate. As the mist evaporates, the energy exchange results in temperature reductions.
Useful tips for mist system layout:
1. Mist line is placed around the perimeter of the area to be cooled. This forms a "mist curtain", a cooling barrier between the protected area and the outside hear.
2. Mist nozzles are placed 24" apart for mist lines mounted 8' to 10' above the ground.
3. For a deep patio, mount the pipe on the inside with nozzles directed slightly downward into the patio for most effective cooling.
4. For a shallow patio, mount the pipe on the outside with nozzles positioned slightly downward and outward.
Layout your system before cementing together:
1. Predetermine hanging position of mist line, inside or outside of patio. Then mark the surface with a chalk line. For proper drainage the mist line should have a 1" downgrade from the highest point of the mist line.
2. Determine where 90-degree turns must be made if you are assembling a mist line around or inside a corner.
3. Measure the lengths needed for straight runs of the mist line.
4. An automatic drain valve must be installed at the lowest point of your mist line to insure proper water drainage when mist system is not in use and to prevent premature nozzle clogging.
5. Determine where you will connect water sources to the mist line. This is your water feedline.
Assemble straight sections of mist line. Connect the precut sections of pipe using the split sections and the PVC cement by liberally applying the cement to the inside of the fitting and the outside of the pipe. Insert pipe into fitting and twist 1/4" turn to evenly spread the cement as each piece is cemented together and provide a water tight seal. Each section should begin and end with a piece of straight PVC. Keep in mind the automatic drain valve placement.
Be sure that the split sections are cemented in place so that all the threaded nozzle openings are aimed in the same directions.
Before mounting, snap one hanging clamp onto the PVC between each split section of prebuilt mist line. Place assembled mist line along your marks with the first nozzle beginning approximately 2 feet from the house and nail hanging clamps into place. Repeat this step until all straight sections are hung.
Join all sections at the corners by cementing 90-degree elbows into place at the corners using the same cementing process. Be sure that the mist line is positioned at the proper angle for misting. This will be the permanent position of the mist line once cement has dried.
To attach the water feedline, cement a 90-degree elbow at the start of the mist line closest to the water source. Point the elbow, and then cement PVC hose adapter to the other end of the PVC pipe section.
To end the mist line, you can choose one of 2 methods:
1. If this is the lowest point in the mist line, cement the threaded PVC 90-degree elbow to end of PVC pipe section facing downward. Automatic drain valve will be placed here after the mist line has been flushed.
2. If this is not the lowest point into the mist line, cap the end by cementing 1/2" PVC cap.
Allow a minimum of 1 hour drying time before flushing system or misting.
Attach sediment filter to the water spigot, then attach water feedline between filter and mist line. Turn on water full pressure for a few minutes to flush out any dirt or debris from within the mist line. Turn off water, hand thread nozzles in the split section opening, and thread automatic drain valve into place. Turn on water and begin misting.
Whenever the mist system is not in use, the residual water should be drained to minimize nozzle clogging. If your system has had an automatic drain valve installed correctly at the lowest points in the system, no additional steps are required after turning off the system.
Nozzles should be cleaned periodically to dissolve mineral deposit build up.
Always remove the nozzles at the end of the summer season.


