Control conditions
Control conditions defrosting
■
If the temperature of the evaporator sensor (BT16) is
below the start temperature for the defrosting func-
tion, JÄSPI Inverter Nordic counts the time to "active
defrosting" for each minute that the compressor is
running, to create a defrosting requirement.
■
Time until "active defrosting" is shown in minutes on
the indoor module / control module. Defrosting starts
when this value is 0 minutes.
■
"Passive defrosting" is started, if the compressor require-
ment has been fulfilled, at the same time as there is a
defrosting requirement and the outdoor temperature
(BT28)is greater than 4 °C.
■
Defrosting occurs actively (with compressor on and
fan off) or passively (with compressor off and fan on).
■
If the evaporator is too cold, a "safety defrost" starts.
This defrosting can start earlier than the normal de-
frosting. If the safety defrosting occurs ten times in a
row, the evaporator (EP1) on JÄSPI Inverter Nordic
must be checked, which is indicated by an alarm.
■
If "de-icing fan" is activated in the indoor module/con-
trol module, "de-icing fan" starts at the next "active
defrosting". "De-icing fan" removes the build-up of ice
on the fan blades and the front fan grille.
Active defrosting:
1. The four way valve shifts to defrosting.
2. The fan stops and the compressor continues to run.
3. When defrosting is complete, the four-way valve
switches back to heating operation. The compressor
speed is locked for a short period.
4. The ambient temperature is locked and the high re-
turn temperature alarm is blocked for two minutes
after defrosting.
Passive defrosting:
1. If there is no compressor demand, passive defrosting
can start.
2. The four-way valve does not shift.
3. Fan runs at high speed.
4. If there is a compressor demand, passive defrosting
stops and the compressor starts.
5. When passive defrosting is complete, the fan stops.
6. The ambient temperature is locked and the high re-
turn temperature alarm is blocked for two minutes
after defrosting.
There are several possible reasons for an active
defrosting to end:
■
If the temperature of the evaporator sensor has
reached its stop value (normal stop).
■
When defrosting has gone on for longer than 15
minutes. This may be due to too little energy in the
heat source, too strong a wind effect on the evaporator
and/or that the sensor on the evaporator is not correct
and therefore displays too low a temperature (at cold
outdoor air).
■
When the temperature on the return line sensor, BT3,
falls below 10 °C.
■
If the temperature of the evaporator (BP8) falls below
its lowest permitted value. After failing to defrost ten
times, JÄSPI Inverter Nordic must be checked. This is
indicated by an alarm.
31
Chapter 7 |
Control
JÄSPI Inverter Nordic
Содержание Inverter Nordic 8
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