GB - 14
38YYS...G
Installation instructions supplement
38YYS...G units are designed to work in North European countries
climates and where cooling is required, even in case of outdoor low
temperatures.
They differ from the standard ones for the following factory fitted
accessories: head pressure controller (HPC), the loss of refrigerant
pressure switch (LRPS) and the high pressure cut-out (HIP).
Operating range
Refer to table III “Operating limits”.
Features
– HPC
(Head pressure controller).
The “HPC” HPC device consists in two parts:
• printed circuit board with fast connection electronic
components;
• temperature sensor supplied with 500 mm of cable,
housed in a special box welded on the outdoor coil.
The insulated printed circuit board (PCB) is equipped
with faston-type terminals and dedicated connection for
heat pump units.
The head pressure controller allows operation in the
cooling mode up to –15
°
C as the condensing temperatu-
re is kept over 41
°
C – 42
°
C.
Thanks to this device, the supply voltage to the fan motor
can be reduced depending on the temperature value
measured on the thermal exchange coil.
Voltage reduction means a reduction in the fan motor
speed and a subsequent rise in condensing temperature.
The HPC measures the fan motor speed automatically
thus allowing the fan to work at its maximum speed.
– HIP
(remote reset by switching from OFF to ON).
High pressure cut-out welded on the compressor
discharge pipe.
Set point
– open at 4200 kPa (42 bar; 610 psig) pressure
– close at 3000 kPa (30.0 bar; 420 psig) pressure
If pressure rises above 4200 kPa (42 bars; 610 psig),
power supply is cut out.
If pressure drops below 3000 kPa (30 bars; 420 psig) the
unit can be restarted by switching power supply off and
then on.
– LRPS Automatic reset loss of refrigerant pressure switch,
welded on the compressor discharge pipe.
Set point
– open at 345 kPa (3.45 bar; 50 psig) pressure
– close at 650 kPa (6.5 bar; 95 psig) pressure
When pressure drops below 345 kPa (3.45 bars; 50 psig)
because of a refrigerant leak, power supply is cut out.
In this case, check the circuit tightness, release air with
the vacuum pump and recharge.
If pressure rises above 650 kPa (6.5 bars; 95 psig) the
unit can be restarted.
햲
Temperature sensor
햳
High pressure cut-out (HIP)
햴
Loss of refrigerant pressure switch (LRPS)
햵
Crankcase heater
햶
Pressure service port
햷
Head pressure controller (HPC)
Heat pump unit
Indoor unit
Outdoor unit
