Software Features And Logic - Lennox BCK 020 Installation Operating & Maintenance Manual

control software features
CLIMATIC 50 SOFTWARE FEATURES AND LOGIC
CLIMATIC™ 50 provides flexibility and the ability to control
multiple Rooftops on a single site.
Enhanced with a 16 bit processor at 14Mhz and a 2
Megabytes flash memory, CLIMATIC™ 50 has been
designed to save energy and to extend the operational life of
the BALTIC product range. It is able to control 50 fault
signals and manage security algorithms generating various
fault signals. In terms of comfort, CLIMATIC™ 50 provides
an innovative PI control.
CLIMATIC™ 50 offers incredible flexibility. For example,
advanced users can go in the heart of the regulation and
adjust the reactivity of the PI algorithm or set the supply
temperature limits .
As a standard feature, CLIMATIC™50 provides 4 scheduling
time zones per day on 7 days. On each of the 4 time zones,
heating set point, cooling set point, minimum fresh air,
humidity set point high and up, and even the different
authorisations for cooling and heating can be adjusted.
CLIMATIC™ 50 provides a choice of different remote
displays depending on customer requirement and applica-
tion of the system. As a standard feature, it is possible to set
alarms (adjustable value low and high) on room temperature
and humidity.
CONTROL SOFTWARE LOGIC
With the CLIMATIC™ 50 Lennox is going away from the
traditional step control
Capacity factor
It is used to determine the exact capacity required at any
time in order to react quicker and more accurately to any
change in demand.
The capacity factor is a percentage of the total cooling or
heating capacity.
Example:
On a three circuit rooftop unit with two compressors running
out of three has a capacity factor of 66%
In the same way, a three circuit rooftop with a modulating
electric heater running at 20% of its full capacity has a CF:
CF = 25%+25%+25%+5% = 80%
The Capacity factor will increase, decrease, or freeze
depending on the temperature difference between the set
point and the room temperature but also on the way this
room temperature is changing:
∆
t i n
+4
CAPACITY
FACTOR IS
+2
FROZEN
0
-2
CAPACITY FACTOR
IS DECREASED
-4
(REDUCE CAPACITY)
Room Temp / Decreasing
Example:
The room set point is 25°C with a 3 compressor unit.
Delta vs
room set Room
point Temp.
+0 Increasing
+1 Increasing
+2 Increasing
+3 Increasing
+2 Decreasing
+1 Decreasing
0 Decreasing
-1 Decreasing
0 Increasing
Reactivity.
The reactivity determines how fast the capacity factor should
vary.
It is given in: Percentage of capacity / >Degree °C ( Room
Temp. VS Set Point) / minute
Example :
If the reactivity is set to 3 % / °C / min
Then:
Capacity factor can go from 0 to 30% in 10 minutes if
Room Temp. VS Set Point is 1°C
Or capacity factor will go from 0 to 60 % in 4 minutes if
Room Temp. VS Set Point is 5°C
The reactivity can be adjusted with the CLIMATIC™ 50 The
larger the reactivity the faster the rooftop will react to a
change.
The next table shows the effect of a change of the reactivity
on the capacity factor: This shows that by increasing the
reactivity, the unit reaches the set point quicker but the
energy consumption (capacity factor) is larger.
IOM / ROOFTOP BALTIC Series - 0803 - E Page 57
P o t S e / m p T e o m R o
Fig. 84
CAPACITY FACTOR
IS INCREASED
(ADD CAPACITY)
CAPACITY
FACTOR IS
FROZEN
Room Temp / Increasing
Table 8
Cap. COMP COMP COMP
factor 1 2
0% OFF OFF
35% ON OFF
70% ON ON
100% ON ON
100% ON ON
100% ON ON
100% ON ON
60% ON ON
60% ON ON
3
OFF
OFF
OFF
ON
ON
ON
ON
OFF
OFF