GEA Grasso 5HP Manual De Instalación Y Mantenimiento página 24

INSTALACIÓN Y PREPARACIÓN PARA EL USO
PREPARATIVOS PARA EL USO
2.
Superheat requirements during operation
Fig.11:
Methods to reduce pressure fluctuations:
•
•
Lubrication Oil
Care must be taken concerning the choice of lubrication oil. Hydro treated mine-
ral oil with a viscosity class 100 is recommended (see oil chart in Product infor-
mation) Other viscosity type of oils are only allowed after a written approval of
Grasso.
Oil separator
If an oil separator is used it is obligatory to insulate the body and fit a thermostatic
controlled oil return protection in the oil return line from the oil separator to the
compressor crankcase.
(Thermostat setting: T = Tc + 20K)
Non condensables
Care must be taken to prevent air/non condensables entering the refrigeration/
heat pump system since it will lead to higher condenser pressures with the possi-
bility to exceed the field of application.
24
Superheat requirements during operation
• To avoid liquid by means of condensation build-up in the suction line the
superheat must be at least 1K above the suction pressure bandwidth,
occurring due to sudden cap. changes and or cylinder capacity regulation,
see in example below.
Superheat requirements
When using cylinder capacity (increase or decrease) regulation the switching
time should not be quicker than 3 minutes between each step.
When using speed control (inverter) the increase or decrease of speed must
be done in such a way that the suction pressures bandwidth is as small as
possible
0089505esp_Pre-release_8
22.03.2017