WattMaster WCC II - Manual (Page 91)

Section 3: Screen Descriptions
WCC II Operator’s Guide
Operator Interfaces 3-59
within normal tolerance -
Locked Mode
The “within normal tolerance” message will appear when the
Optimal Start Screen is in the locked mode when the space
temperature reaches the target temperature within 2 minutes of
when the week schedule for this screen goes ON.
Adaptive Mode
The “within normal tolerance” message will appear when the
Optimal Start Screen is in the “adaptive mode” if the space
temperature reaches the target temperature within the number of
minutes equal to the difference between the actual temperature
and target temperature when the optimal start began. That is, if
there was a 10 °F difference between the actual temperature and
the target temperature when the Optimal Start Program began, then
the “within normal tolerance” message will appear if the space
temperature was at the target temperature within 10 minutes of
when the week schedule went ON.
OUTDOOR READING
Enter two values under the outdoor reading heading—the top
value and the bottom value. The computer automatically fi lls in the
values between these two numbers at even increments. Usually, the
highest outdoor air temperature expected is input at the top, and the
lowest outdoor air temperature expected is input at the bottom.
ADVANCE TIME
This is a user-entered fi eld which corresponds with the Outdoor
reading. These values also correspond with the message to its right
which states:
Advance time is measured in minutes/1.0 Deg F
difference between indoor and target
temperatures.
In the LOCKED mode, the system will always use these advance
start times. In the ADAPTIVE mode, the system will automatically
adjust these values based on previous system performance.
The Optimal Start Program reads the indoor temperature and
calculates how far it is away from the target temperature. It also
reads the outdoor temperature and then determines the start time
needed to bring the building to the target temperature. The largest
number which may be entered in this position is 99.99.
For example, assume the outdoor temperature is 45 ºF, the indoor
temperature is 65 ºF, and the indoor target temperature is 70 ºF.
Outdoor Temperature: 45 ºF
Indoor Temperature : 65 ºF
Target Temperature : 70 ºF
From the Advance Start Table, the advance start time is 12.11
minutes per ºF.
The difference between the indoor and target temperatures is
5 ºF.
Target Temperature: 70 ºF
Indoor Temperature: 65 ºF
-----------
Difference: 5 ºF
Therefore, the advance start time is 60.55 minutes.
12.11 x 5 = 60.55 MINUTES EARLY START
If you have selected the “adaptive” mode, and the space temperature
does not reach the target temperature when the schedule associated
with this optimal start program goes ON, the system will
automatically increase the advance start time. If the space reaches
the indoor target temperature before the schedule goes ON, then
the system will automatically reduce the advance start time.