Gattetti LCA User Manual page 24

Water chillers and heat pumps
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d4: End-defrosting temperature/pressure
It indicates the temperature or pressure threshold which makes the defrosting cycle end.
d5: Minimum time-interval before starting a defrosting cycle
It indicates the time-interval necessary to carry out the d3 condition, before a defrosting cycle is started (the compressor
must be ON).
End defrosting T/P
Start defrosting T/P
d6: Minimum defrosting time
Minimum duration of the defrosting cycle (defrosting continues even if the condensation probe measures values higher
than the defrosting temperature/pressure end). Set d6 = 0 to ignore this function.
d7: Maximum defrosting time
With a time-based defrosting (d2=0), it represents the actual duration of defrosting; if, on the contrary, a
temperature/pressure-based defrosting has been selected, this parameter will indicate the maximum duration of
defrosting (an alarm message will appear on the display).
d8: Time-interval between two defrosting cycles in the same circuit
Minimum time-interval between two successive cycles in the same circuit.
d9: Defrosting time-interval between the two circuits
It indicates the time-interval between the defrosting cycles of the two circuits. If d9 = 0, defrosting in the two circuits will
be performed at the same time.
dA: Defrost end detected by an external digital contact
It activates the end of defrosting cycle from digital contact (for example a pressostat). The contacts are to be connected
in the place of the condensation-removal fan overload (ID4 for circuit1 and ID11 for circuit2). By enabling the end of
defrosting from digital input (dA=1), the defrost procedure starts normally (by condenser temp/press threshold) plus a
control for the closed status of the defrost end digital input; the end of defrosting is detected with an OPEN contact.
Value
Selection
0
end of defrosting detected by a NOT enabled external contact
1
end of defrosting detected by an enabled external contact
db: Defrosting of antifreeze/support heaters
The parameter sets if, during defrosting, the antifreeze/ support heaters must be activated so as to limit the flow of cold
water/air in the environment. With a two-compressor unit, the heaters to be activated are those relative to the circuit
which is effecting the defrosting. The meaning of this parameter is as follows:
Value
Selection
0
antifreeze/support heaters NOT activated during defrost
1
antifreeze/support heaters activated during defrost
RG66000889-REV.OO
Temperature-based defrosting (d2=1)
Min. time-interval to start a def. cycle
Timer reset
24
Start defrost
Min. defrosting interval

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