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Operation and maintenance instructions
Envistar / CRAMO
DSCR111125.01
Air handling with the focus on LCC
Continuous product development may give rise to specification changes without prior notice.
Operation - Control
Interlocking
The cooling unit is interlocked across the supply air and extract air fans. If any of
the fans stops, the cooling unit will also stop.
Operation
Heat recovery rotor operation
When the supply air/room air temperature is below the outdoor air temperature
and cooling is required, the heat recovery rotor will start up and operate at full
speed to recover cooling energy.
Cooling operation
The cooling compressor starts when the potential-free contact from the control-
ler closes.
Interlocking
The compressor is interlocked with the ventilation unit. When the ventilation unit
stops, the potential-free contact for cooling operation opens and the compres-
sor stops.
Compressor Protection
The motor protection trips, the compressor stops, the group alarm contact clos-
es, and an alarm is transmitted to the controller in the event of an over-current or
safety circuit alarm. In the event of an alarm, remedy the fault and reset the mo-
tor protection.
N.B!
Each high pressure switch has a manual reset button.
The safety circuit alarm trips in the event of two different kinds of faults.
• High pressure in the system, HP
• Low pressure in the system, LP
If the safety circuit alarm trips repeatedly, contact an authorised refrigeration
service firm.
Electrical Connections
Junction box contains the following:
• Protective motor switch
• Contactor
• Starting equipment
• Condenser for size 04
The junction box is mounted in the cooling unit and has been internally fully
wired and tested at the factory.
Note the sequence of the colling unit power supply phases!
If the phase sequence is wront, the compressor will rotate in the wrong direction
and this will reduce the cooling capacity and increase its noice level. See the
Section on Fault Tracing.
