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FR · ERC 21X user manual · DKRCC.ES.RL0.H3.02/520H9656 · ©Danfoss
2|
Key features
2.1| Voltage protection
Protection against high and low voltage by limiting the
compressor operation within specified voltage limits.
Whenever the supply voltage goes beyond the defined
voltage protection limits controller will shut the compressor
OFF and flashes alarm on the display.
It will restore the operation when the voltage falls under the
operating range respecting minimum stop time.
2.2| Compressor protection
Parameters for Minimum ON and OFF time, protect the
compressor by short cycling/sudden switching ON and OFF
by defining minimum ON and OFF time.
2.3| Compressor protection against
high condensing temperature
If the condenser is blocking up with dirt and thereby reaches
a too high condensing temperature, controller will give
the user early warning through condenser alarm and if
temperature rises further it will switch the compressor OFF.
If the temperature measured by the condenser sensor (Sc)
is reaching the set ”
pre alarm limit
” a alarm is raised, but no
further action is taken.
This is used to indicate to the user that something is wrong
with the condenser. Often the reason is that that the air flow
to the condenser is restricted (dirt) or because the condenser
fan is broken.
The alarm will reset if the condenser temperature drops back
by 5 °C. If the measured condenser temperature continues
to increase and reaches the set “
Block limit
” the compressor is
stopped and it is restricted from starting again until the alarm
is reset manually.
High voltage limit
High voltage cut-in
limit (compressor start)
Low voltage cut-out
limit (alarm and
compressor stop)
Po
wer to compressor
min run time
ON
OFF
CUT-IN
CUT-OFF
min stop time
time
time
Temperatur
e
Sc temperature °C
Sc temperature °C
Block limit
Pre alarm limit
Pre alarm OK
Compressor
Pre alarm
Block alarm
T1 T2
T3 T4
