6 | commissioning – GEA Bock HGX2 CO2 T User Manual
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6 | Commissioning
The	compressor	is	fitted	with	two	decompression	valves.	One	valve	each	on	the	
suction	and	discharge	side.	If	excessive	pressures	are	reached,	the	valves	open	
and prevent further pressure increase.
Thereby CO
2
is blown off to the ambient (see also Chapter 7.6)!
In	the	event	that	a	pressure	relief	valve	activates	repeatedly,	check	valve	and	
replace	if	necessary	as	during	blow-off	extreme	conditions	can	occure,	which	
may	result	in	a	permanent	leak.	Always	check	system	for	refrigerant	loss	after	
activation of pressure relief valve!
6.7 Decompression valve
CO
2
streaming
out
Fig. 21
6.6 Start-up
WARNING! Ensure that both shut-off valves are open before starting the
compressor!
Check that the safety and protection devices (pressure switch, motor protection, electrical contact
protection measures, etc.) are functioning properly.
 Switch on the compressor and let it run for at least 10 minutes.
 The	machine	should	reach	a	state	of	equilibrium.
 Check the 
oil level: The oil level must be visible in the sight glass.
After a compressor is replaced, the oil level must be checked again. If the level is too high, oil
must be drained off (danger of oil liquid shocks; reduced capacity of the refrigerating system).
ATTENTION! If larger quantities of oil have to be topped up, there is a risk of oil
impact effects. If this is the case, check the oil return!
The decompression valves do not replace any pressure switches and the 
additional safety valves in the system. Pressure switches must always be installed 
in	the	system	and	designed	or	adjusted	in	accordance	with	EN	378-2	or	appro-
priate safety standards.
Failure	to	observe	can	result	in	risk	of	injury	from	CO
2
streaming out of the two
decompression valves!
