User Guide
|
Intelligent Purger System (IPS) for Ammonia - Technical data, installation, and use
© Danfoss | DCS (hhr) | 2019.02
BC297731816824en-000101 | 148R9643
| 5
Working cycle
The Danfoss IPS operates in 24-hour cycles, of
which 45 minutes are dedicated to a R404A pull
down . At power on, the pull down is initiated
immediately . If no NC gases are detected during
the 45 minute pull down, the system will stand
by for 23 hours and 15 minutes before another
pull down is performed .
To identify NC gases, the controller utilizes
upper and lower thresholds for R404A
evaporating temperature . If, during pull down,
the temperature continues decreasing and the
lower threshold is passed, the controller consider
this to be a high concentration of NC gases
and opens the purge solenoid valve . The purge
valve will stay open until sufficient condensing
ammonia is present to lift the R404A evaporating
temperature above the upper threshold .
The compressor will continue running and if the
temperature again decreases below the lower
threshold, a new purging will be performed . This
process will be repeated until the evaporator
temperature stays above the lower threshold
for 45 minutes after the previous closing of the
purge valve .
Fig. 2 - Power on & Cycle at no NC gases present: CST (compressor start time) and PDT (pull down time) are configurable
Fig. 3 - Purging procedure - Low R404A evap. temperature detected during PDT: Tresholds are configurable.
* If low evaporator temperature is detected (passing lower threshold), the purging procedure will be repeated immediately .
Cycle (CST). 24 hours
Purger
Pull
down
(PDT):
45
mi
n
Cycle (CST). 24 hours
Purger
Pull
down
(PDT):
45
mi
n
Time
Power on
Purger
Pull
down
(PDT):
45
mi
n
On
O
ff
On
O
ff
Compressor
Purge valve
Time
On
O
ff
On
O
ff
Compressor
Purge valve
Evaporator
Temp
.
Upper Threshold
Lower Threshold
Non condensables has been purged
- new cycle starts *
