Hired-Hand Farm Hand Series: Vent Master 16 Stage - Manual (Page 6)

Part No. 4801-5098 Farm Hand Vent Master 3
This controller has only two basic pressure settings, a Target Pressure, and a Pressure Differential. The
Target Pressure is the static pressure that the system tries to maintain within the limits of the Pressure
Differential. The Pressure Differential is the range around the Target Pressure that is considered
satisfactory. From the Target Pressure and the Pressure Differential the High and Low Pressure limits are
calculated. The High Pressure limit is the Target Pressure plus half of the Pressure Differential and the
Low Pressure limit is the Target Pressure minus half of the Pressure Differential. The controller will open
and close the vents as needed to maintain pressure between the high and low limits.
Low Pressure
High Pressure Limit
Low Pressure Limit
When pressure is
in this range, the
controller will not
adjust vents.
When pressure is
above the high
limit, the vent
machine will open
vents to lower
pressure.
When pressure is
below the low
limit, the vent
machine will close
vents to raise
pressure.
High Pressure
Room Pressure
Now that we know how the pressure limits are established, lets move on to how to set up those limits.
Press the mode button a few times, and you will see that the display changes each time. If you will look
just to the right of the display, you will see four green lights labeled Temperature, Static Pressure,
Var/Timer Percent, and Target. The green light tells you what setting you are looking at in the main
display. If the light beside Static Pressure is lit, the numbers in the display show you the current pressure
in your building. However, for viewing Target Temperature both the LEDs beside “Target” and
“Temperature” will be lit. For viewing Target Static Pressure both the LEDs beside “Target” and “Static
Pressure” will be lit.
Assume that you have this controller installed in your house, and you decide you want pressure to be kept
a little bit lower. You walk to the controller, press and release the mode button, watching the green lights
until the “Target” and “Static Pressure” LED is lit. If you look at the display now, you see the present
setting for the Target Pressure. To lower it, press and release the minus (-) button until you see the new
limit you want. The controller will now start operating using your new limit. If you want the Vent
Master to maintain the Target Pressure within narrower limits decrease the Pressure Differential. See
Section 7 for a graphic example using the Target Pressure and Pressure Differential.
6. Why Use a Pressure Controller?
The Farm Hand Vent Master is used to control vent inlets in agricultural enclosures. Maintaining a slight
negative pressure inside a building ensures that air flows in evenly from all openings in the building.
However, as static pressure increases, the speed and volume of the incoming air increases. It is important
to set the pressure at an appropriate level to ensure maximum efficiency. Too little vacuum, and the
livestock could suffer from drafting, and temperature shock. Too much vacuum, and fan efficiency is
reduced, increasing the levels of moisture, ammonia in the enclosure, and also driving up electricity costs.