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

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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.
■ Never touch the wiring chambers (heat pump
control unit and power supplies for internal
and external units, see chapter "Internal unit:
Overview of connections" and "External unit:
Overview of connections").
■ When working on the appliances (internal/
external units), isolate the system from the
power supply, e.g. at the separate MCB/fuse
or at a mains isolator. Check the system is no
longer 'live' and safeguard against reconnec-
tion.
■ Prior to working on the appliance, wait at
least 4 min until the voltage has completely
dropped out.
Danger
The absence of system component earthing can
lead to serious injury from electrical current and
component damage in the event of an electrical
fault.
Always remake all earth connections.
The appliance and pipework must be connected
to the equipotential bonding of the building.
!
Please note
Commissioning immediately after installation
can lead to appliance damage.
Wait
at least 30 min between installing and
commissioning the appliance.
!
Please note
Refrigerant can escape when working on the
refrigerant circuit.
Work on the refrigerant circuit must
only be car-
ried out by a certified contractor (in accordance
with EC 842/2006 and 303/2008).
1. Remove front panel: see page 17.
2. When work is complete, close the heat pump: see
page 48.
For commissioning this appliance, see also the
operating instructions.
Compiling reports
Enter the readings taken during commissioning into
the reports from page 114 and the operator's log (if
available).
Purging the refrigerant lines and indoor unit
Purge the refrigerant lines and the internal unit with
nitrogen. The internal unit is filled with nitrogen (positive pres-
sure approx. 2 bar/0.2 MPa).
Checking the refrigerant lines for leaks
Performing a tightness and pressure test with dry nitro-
gen at 43 bara/4.3 MPa.
Commissioning, inspection, maintenance
Opening the heat pump
5776 028 GB