Viessmann AWT 221.A04, Installation And Service Instructions For Contractors

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58
Checking electrical connections of the outdoor unit for firm seating
Danger
Contact with 'live' components can lead to seri-
ous injury from electric current. Some compo-
nents on PCBs remain 'live' even after the
power supply has been switched off.
■ When working on the external unit, isolate the
system from the power supply, e.g. at a sepa-
rate MCB/fuse or a mains isolator. Check the
system is no longer 'live' and safeguard
against reconnection.
■ Prior to working on the appliance, wait at
least 4 min until the voltage has completely
dropped out.
Closing the heat pump
See page 48.
Switching on the power supply
Switch on the power supply at the main MCB/fuse.
Starting the heat pump
!
Please note
Operating the appliance with insufficient refriger-
ant results in appliance damage.
■ Before starting the appliance, the internal unit
and the refrigerant lines must be charged with
the indicated amount of refrigerant: See chap-
ter "Charging the refrigerant lines and internal
unit".
■ The refrigerant circuit must be checked for
tightness: See chapter "Checking the refriger-
ant circuit for tightness".
■ The fill valves on the external unit must be
open when the appliance is switched on: See
chapter "Charging the refrigerant lines and
internal unit".
Follow the sequence shown
1. Switch ON external unit voltage.
2. Wait 2 min.
3. Switch ON internal unit voltage.
4. Start internal unit at the ON/OFF switch.
Note
If the internal unit is switched on before the external
unit or the waiting time is shorter than 2 min, the fault
message
"0A Fault external unit" appears.
"Vitotronic 200" service instructions
Commissioning, inspection, maintenance
Checking the thermal insulation of flared connections
5776 028 GB