Gattetti LCA User Manual page 27

If P6=1 the operating logic of the cooling/heater selection is reversed (both by keypad, infrared remote controller and digital
input).
Symbol P6=0
Cooling (chiller)
Heating (heat pump)
P7: Low pressure alarm with pressure probe
If P7=1 with the heat pump selection lower than 1bar (obviously the presence of the condenser-pressure probes must be
enabled, parameter /3) and the low pressure alarm is activated (by maintaining in any case the possible delay P3). If
P7=0 such operating is disabled.
General parameters ("H")
H1: Machine model
It allows to select the type of machine to be controlled:
Value Unit
0 AIR/AIR unit (only cooling)
1 AIR/AIR heat pump
2 AIR/WATER chiller
3 AIR/WATER heat pump
4 WATER/WATER chiller
5 WATER/WATER heat pump with gas reversibility
6 WATER/WATER heat pump with water reversibility
7 Motocondensing unit
8 Motocondensing unit with reversing refrigerant cycle
H2: Number of ventilating circuits
It indicates the number of fan circuits in two-compressor configurations. When there is 1 fan circuit selected, the unit will
activate the control of fans on the basis of the higher temperature/pressure in the 2 circuits. The Y1 output is managed in
parallel with Y2; therefore, it is possible to connect two fan regulation boards increasing the "size" of the fans that can be
managed by µchiller.
H3: Number of evaporators
It indicates the number of evaporators in two-compressor configurations. When there is one evaporator, heaters
management and antifreeze control will be performed only by B2.
H4: Capacity-controlled/Compressors in parallel mode
In two-compressor units, this parameter allows to set two compressors or one compressor with capacity-controlled
routine. When using one capacity-controlled compressor, the alarm inputs relative to the second compressor will not be
used and B4 and B5 measurement will not be detected. Rotation is disabled.
In single-compressor units (the expansion board must not be installed) the H4 parameter is used to enable the control of
possible Tandem compressors (operating in parallel in the same circuit). With this configuration:
• the pump output (PUMP silk screened directly on the board) is activated, besides in the typical modes indicated in H5
parameter, also when activating the antifreeze heaters (both in normal operating and in stand by)
• the output RES1 is used to manage the second compressor.
In Tandem units compressors are activated as in normal operating mode (at 50% and at 100% of the differential) with a
time-based rotation (every 30 seconds the activation priority is inverted); in case of defrost the activation of both
compressors is forced.
The rest of features performed is as equal as the standard algorithm followed for 2 Compressor machines.
RG66000889-REV.00
P6=1
Heating (heat pump)
Cooling (chiller)
(not applicable)
(not applicable)
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