V2.2
-00
13
CONTROL OF CONDENSER FANS
Function
To maintain as stable a condensation pressure as possible without fans cutting in too frequently.
Description
The CLIMATIC calculates the number of ventilation stages THVn required for the proper functioning of each
refrigeration circuit.
THVn depends on the following parameters :
PTHPn
ó
Condensation pressure in circuit n (abs. bar)
TEA
ó
Outside air temperature (°C)
HPHAUT
ó
High pressure limit (abs. bar)
HPBAS
ó
Low pressure limit (abs. bar)
The minimum difference between HPHAUT and HPBAS is 5 bar.
TEMPOV
ó
Timing of raising or lowering of ventilation stage (s)
F
Fan operation
At the start-up of the first compressor on the circuit, as soon as high pressure becomes greater than
HPBAS+1bar, N fans are immediately started up (the number N depends on the outside air temperature).
When PTHPn exceeds HPHAUT, the thermostat is increased by one stage. If the pressure remains above
HPHAUT, THVn continues to be increased by one unit every T (time interval) :
.
If HPHAUT < PTHPn 1bar,
T = TEMPOV
.
If 1bar < PTHPn 2bars,
T = TEMPOV/2
.
If PTHPn > 2bars,
T = TEMPOV/4
F
Turning off fans
Once PTHPn falls below HPBAS, THVn is reduced by one stage. As long as PTHPn remains below HPBAS,
THVn continues to be decreased by 1 every TEMPOV (time interval).
Note
:
When stopping a ventilation stage relates to a 2-speed fan, switching from fast to slow speed is
delayed by 5 seconds.
Setting
instructions
THVn
HPHAUT
1bar
2bar
HPBA
S
HPBAS+1bar
time
PTHPn
.
At t=0, start-up of
1st compressor
.
N=1
.
τ
= TEMPOV
τ
τ
/2
τ
τ
/4
0
0
1
2
3
4
5
4
3