FläktGroup Multi-DENCO, Operation Manual

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Multi -DENCO Commissioning
FläktGroup DC-2013-0101-GB • Subject to modifications • R4-05/2018 83
Adding refrigerant
The initial 'charge' of refrigerant that is added to the system is not an exact measure,
but a volume of refrigerant to enable the system to start initially. This first charge should
always go into the liquid line of the unit and be approximately 75% of the planned
charge amount.
Your sales/support representative should be able to give you an estimate of total
system charge (if supplied with the required information).
•
Add an 'inital-charge' of refrigerant R410A until 'high' and 'low' side pressures are
equal. Be careful that no liquid refrigerant is injected into the compressors.
•
Close off the manifold valves and record the quantity of refrigerant added.
8.3 Commissioning procedure
8.3.1 Room considerations
During commissioning, it is important to understand the heat load and the ambient tem-
perature in relation to:
– Initial design conditions
– Current conditions (during commissioning)
– (Possible) future conditions
For example, attempting to commission a Multi -DENCO A-Version unit in a room with
no heat source is difficult, as you would not be able to give a consistent operation to
observe refrigerant charge. Alternatively, commissioning a unit on a cold day could
result in lower condensing temperatures, which may cause over-charging of a unit.
Wherever possible, attempt to recreate the required conditions needed by the end
user, so that the unit is configured for the appropriate operating range. Always consider
that the ambient temperature on initial design conditions, may only be 'peak' tempera-
ture and that the unit will probably be operating at lower temperatures for a significant
percentage of operation.
NOTE!
It is important that the volume of refrigerant added during the initial charge is recor-
ded accurately. When commissioning it is a
LEGAL REQUIREMENT for the total
refrigerant weight to be added to the unit's nameplate. Ensure the pre-charge mea-
surement is accurate and this information is provided to the commissioning
engineer.
NOTE!
Due to the complex nature of the Multi -DENCO product, we strongly recommend
that a FläktGroup commissioning engineer is employed to carry out the commissio-
ning procedure. Contact your local representative for assistance with this.