You can supply multiple heads in zones supplied with a single liquid feed line. Make sure the line is adequate for the expected liquid flow (each fog head consumes 0-10 oz [0-300 ml] per minute]). 1/4" ID tubing is adequate to supply 3-6 heads and 1/2" for 8-20 heads. If you have any questions, contact the factory.

A vernier valve on the fog head lets you adjust liquid flow and fog droplet size (higher flow = larger droplets). Set droplet size after completing installation; otherwise changes in head elevation or liquid pressure could affect the setting.

You can mount fog heads wherever you need them -- on walls, ceilings or posts. Four stainless mounting tabs are included. And you can move heads around if your needs change. Since no expensive piping must be rerouted, the cost is minimal. Just plug the head into an electrical outlet and connect the liquid source.

Optimum feed line pressure is 15-25 psi (at the head). If the pressure is too high, you may find it difficult to adjust output particle size accurately. That's because valves are less able to regulate small flows when working against a large pressure drop. To remedy this problem, install a step down pressure regulator (available from Fogmaster and numerous third party sources) in the liquid line.
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Liquid Delivery Alternatives

There are many ways to manage the feed liquid to produce pressure and control fog heads. The best one depends upon your specific situation. Two sections below describe using a pump and a direct connection to the building water supply. Of course there are many other possibilities. If you have a question, ask us (e-mail to Fogmaster).

Pump Method

This approach uses a tank or liquid reservoir to hold fogging liquid. When fogging is required, a transfer pump is turned on, pressurizing the liquid delivery line and activating fog heads. (To download full size drawing, click image.)

The pump must develop enough pressure to lift liquid to the highest fogging head, plus 10 psi to activate the pressure switch.

Use caution interpreting the flow and pressure data in pump literature. Pressure data may mean maximum pressure under no flow conditions or flow data may be given for zero pressure conditions.

Data on pump performance under operating conditions are found in the pump's characteristic curve which plots pressure vs. flow through the full operating range. The pump manufacturer should be able to supply this information.

The pump must be capable of developing a minimum pressure equal to the static lift to the highest head, plus 10 psi to activate the pressure switch. To calculate the minimum pressure, measure the height of the highest fogging head (in inches) above the low liquid level of the reservoir. Divide by 27 to convert to psi. If your fogging liquid is heavier than water, multiply by the density of your liquid and divide by the density of water. Finally, add 10 to get the required pump pressure (in psi).

The pump must deliver enough flow (at operating pressure) to satisfy the consumption needs of all fog heads which are to operate simultaneously. Pump flows are normally quite modest; a system of 12 heads, each running wide open, requires less than one gallon per minute of diluted liquid.

It's best to select a pump which is properly sized for the application. Too large a pump will waste energy and may develop too much pressure, reducing the sensitivity of fog head droplet size control valves. In this case, install an in-line pressure reducer or a bypass return line at the pump. (To download full size drawing, click image.)

A small fog system might consider Fogmaster's Model 6300 Pump-R transfer pump. It delivers an adequate flow and pressure to support one Sentinel II head at a time.
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Direct Connection Method

As shown in the drawing, you can supply fog heads directly from the building water supply. A shut-off valve, backflow preventer and particulate filter should also be installed, especially if you use a chemical injector. Check local plumbing codes for requirements.

If you are fogging only water, say for humidification, evaporative cooling or dust settling, this is all you need.

If you are fogging a chemical concentrate diluted with water, you can put a chemical injector in the water feed line. Automatic dilution saves the cost of a liquid reservoir and the labor to mix chemical by hand. It also simplifies changes in chemicals or dilution ratios. Injectors should be installed with pipe unions or flexible connections so they can be removed for servicing.

Injectors are available from many sources. Fogmaster offers a non-electric model with adjustable mix ratio up to 1:500. Water moving through the unit drives a mechanical lift which pulls concentrate into the discharge stream. This injector operates reliably at water flows as low as 2 gallons per hour.

A direct connection also eliminates need for a pump since house water pressure (45-75 psi) is more than adequate. However, you may need a pressure reducer for better control of droplet size.

To change chemicals, simply change concentrate bottles (First flush out the line to minimize mixing between the two concentrates). If you plan to fog several chemicals at once, install a separate injector for each. This avoids mixing concentrates and allows mix ratios to be changed if needed. Injectors should have an internal bypass, or be plumbed with external bypass.
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Many installations use a repeat cycle timer to control fog operation, turning a pump or solenoid valve(s) on and off. Fogmaster's Model 2238 RC Timer offers separately adjustable on / off times (1-100 minutes each) and 15A contacts. If time of day control is needed as well, put a clock timer before the RC timer.
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The only required maintenance is to clean the air filter (the frequency would depend on your conditions) and to replace motor brushes when they wear out. Sentinel II fog heads are equipped with a Motor Saver brush. When it wears out, it stops the motor so brush housings don't scratch the commutator.
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