Hired-Hand System 100 Variable Speed Controller - Manual (Page 4)

System 100 Variable Speed Controller
4801-2974 December 21, 1995
2
Internal Controls
The controller has three controls on the inside that control the operation of both the stages, and the
settings for the variable speed fan stage. These controls should only need adjusting if your setup
requires a major change.
WARNING: Do not open controller box for any reason with power applied to the controller.
This jumper controls the stage programs (offset
and differential). Without the jumper installed,
the controller will be in program A. If the
jumper is installed, the controller will be in
Program B.
Program A is designed to give a strict
temperature control, whereas program B is
designed with a greater temperature range that
satisfies the controller, thus using less power
(less hunting, and overshoot). Each program is
detailed later in this manual.
The Variable Minimum adjustment sets the
minimum speed (in percent) of the fan. The fan
will run at minimum speed whenever the
temperature at the sensor is less than or equal to
target temperature.
The variable span is the difference in degrees
Fahrenheit between target temperature, and the temperature the fan
reaches maximum speed. For example:
Target Temp 74F
Variable Span 2 degrees
Fan will be at 100% (maximum speed) at 76F.
The speed increase is smooth. (For every one degree temperature increase,
the fan speed will increase the same amount for the full range of the controller.) The drawing on the
next page explains this linear increase.
STAGE PROGRAM
OFF = PROGRAM A
ON = PROGRAM B