Cumberland EDGE 890-00601, Installation And User Manual

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Chapter 12: Ventilation operation
Figure 12-1 Minimum ventilation and bandwidth
Variable stages — Variable stages can be made up of variable fans or of On-Off fans on modulating
timer. For a variable capacity stage, start temperature is calculated based on minimum set capacity and
maximum temperature is calculated based on maximum set capacity
Variable stages with variable fans —
Ventilation stages can be assigned to variable fan groups . Minimum and maximum capacities, in percen-
tages, can be set for each group on each variable stage.
When the minimum ventilation requirement is lower than the floor minimum capacity of a variable fan
stage, the variable fans work on a timer set in the Power ventilation setup. Then as the house/barn tem-
perature increases, the on time portion of the cycle increases until full time operation is reached. Then, as
temperature rises and deviates from set point, the fan speed increases until it reaches the set maximum
stage capacity.
To remove dust and ice, variable fans are started at 100% of their capacity for 4 seconds then decelerated
to the desired capacity. Inlets don’t follow the temporary (4 seconds) variable speed burst.
Variable stages with on/off fans
If only On-Off fans are used on a variable stage; to make the stage variable, one group of fans is set with
a minimum and a maximum capacity, in percentage.
This fan group operates on a cycle timer. The on time of the fan group is modulated between the stage’s
start and maximum temperatures.
The on time portion of the cycle increases as the house/barn temperature increases, until it reaches the
set maximum stage capacity.
Fan rotation and CFM calculation
Rotation is meant to prevent wearing. Instead of always using the same group of fans on a stage, one or
many fan groups of the same capacity can be used in sequence on this stage. Only fan groups with the
same CFM capacity can be assigned to rotation. There must be at least two identical fan groups to use
895-00693 EDGE 113