Description Of The Defrosting System; Initial Defrosting Temperature; Delay Between Two Defrosting Requests; Maximum Defrosting Duration - Lennox CLIMATIC 200 User Manual

DESCRIPTION OF THE DEFROSTING SYSTEM

The defrosting process is activated during heating mode in heat pump units, when the outside temperature is low
and the outdoor coil could become frozen.
To melt the ice the defrosting function will switch the unit to cooling operation for a short period.
During defrosting mode the low pressure is at minimum level, consequently the pressure switch is disabled in this
mode.
The manufacturer uses default control settings which apply to most installations. The set parameters determine
the following:

INITIAL DEFROSTING TEMPERATURE

The defrosting cycle begins when outdoor probe pression is below 5,7 bar.
END DEFROSTING CYCLE
The defrosting cycle ends when outdoor probe pression of the refrigerating pipe reaches 35 bar.

DELAY BETWEEN TWO DEFROSTING REQUESTS

Time between two defrosting cycles is calculated from the end of one to the beginning of next, and it is 30 minutes.
This defines the time during which the initial defrosting pression must be maintained. When this time has elapsed,
the unit starts to defrost. If the initial defrosting increases before this time has elapsed, the timer would block and
it would only start to count when the temperature returns below the starting defrosting pression. This pausing
prevents the unit from carrying out continual defrosting patterns.

MAXIMUM DEFROSTING DURATION

It is the maximum defrosting time.
This defines the maximum period if the temperature has not exceeded a set value.
This timing prevents too long defrosting cycles.
The maximum defrosting time will be 5 minutes.
DEFROSTING CYCLE SEQUENCE:
When the defrosting cycle starts the compressor stops, the four-way valve reverses 30 seconds and after 30
seconds, the compressor starts. This cycle ends when the outside exchanger probe detects the final defrosting
pression or exceeds a safety interval. When the defrosting cycle has finished, the compressor stops 30 seconds.
Then the four-way valve reverses and 30 seconds later, the compressor starts again in heating mode generating
again warm water more efficiently due to the absence of frost.
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