Technical information
14
Operation, cooling and hydraulic diagram, YLHA 50 - 80 (heat pump)
Cooling cycle
The 4-way valve is activated. Heat exchange takes place
between the heat transfer liquid (water or glycol water) and
the refrigerant in the plate heat exchanger. Water is cooled,
and refrigerant is evaporated and reheated. Then the Scroll
type compressor condenses the refrigerant (gas) until the
condensing pressure is reached, and the refrigerant goes to
the air cooled condensing unit. In the air cooled condensing
unit, heat is exchanged between the air and the refrigerant.
The air is heated and evacuated from the chiller (heat rejec-
tion). The refrigerant is condensed and sub-cooled. Then the
refrigerant (liquid) goes on to the expansion element, where
it is expanded until the evaporating pressure is reached, at
which time it goes to the plate heat exchanger to start a new
cooling cycle.
Heating cycle
The cycle is reversed to heating mode. The 4-way valve is
not activated. The condensing unit becomes the evaporating
unit, and the evaporating unit becomes the condensing unit.
The water in the plate heat exchanger is heated.
SAFETY/CONTROL DEVICES
A High pressure switch
B Low pressure switch
E Pressure transducer port.
Fan speed setting, defrost management,
condensing pressure display (cooling
cycle)
or evaporating pressure display (heating
cycle)
F Water outlet temperature sensor
(Antifreeze, setting and display)
G Water intake temperature sensor
(Setting and display)
COMPONENTS
1 Tandem compressor
2 Air cooled condenser
3 Filter dryer
4 Sight glass
5 Expansion valve
6 Heat exchanger
7 Heat exchanger antifreeze heater
8 Globe valve
9 4-way valve
10 Retainer valve
11 Liquid receiver
12 Automatic air bleed
13 Expansion vessel
14 Relief valve
15 Water pump
16 Flow switch
17 Drain connection
18 Water filter (not inside the unit)
Pipe connection with Schrader valve
For units with hydro kit only