Servicing and Maintenance Multi-DENCO
120 FläktGroup DC-2013-0101-GB • Subject to modifications • R5-08/2020
10.3 Refrigerant leak testing
Leak testing on the equipment is required:
– After any strength affecting work (e.g. Brazing)
– If the unit has not operated for longer than two years
– Changes or extensions to the system
– Suspicions of refrigerant leakage
–On Multi-DENCO systems with a R410A refrigerant charge of 2.4 - 23.9 kg (equiva-
lent 5 - 50 tonnes CO
2
) a yearly leak test is mandatory.
– On systems with charges of 24 - 239 kg (equivalent 50 - 500 tonnes CO
2
) then it is
mandatory to perform a leak test twice a year.
– Within one month of fixing a refrigerant leak
10.4 Compressor care
On new Multi-DENCO systems, if installed and commissioned correctly, no acids are
present. Multi-DENCO units are fitted with molecular sieve type of drier to help mois-
ture content be at an extremely low level.
If the system has operated under adverse conditions for some time, weak acids may
appear from the oil and refrigerant by system heat and electrical arcing. This acid will
remain INERT until moisture is added to the system, for example, via air ingress into
the system during service work.
10.5 Cleaning the heat exchanger of Water Cooled System (Flushing)
W-Version In fault finding or general maintenance, it is good practice to observe the pressure drop
across the brazed plate heat exchanger. If the value is significantly higher than what
was recorded at commissioning, then fouling of the heat exchanger may have
occurred, affecting the components performance.
Cleaning or ‘back-flushing’ can be performed using the water connection points (if fit-
ted) provided within the WaterCool module.
P-Version Access into the Shell & Tube heat exchanger can be made at the end plates, however
as the P-Version is a self-contained system, there should be very little or no fouling
within the heat exchanger, if commissioned correctly.
If it is planned to conducted cleaning of the heat exchanger, regardless of the previous
statement, then consideration must be made to the access space to the side of the
close control unit.
10.6 Humidifier maintenance (if fitted)
As the humidifier usually operates in automatic mode and the relevant wear of the
device is displayed, a standard maintenance interval is usually sufficient. Cylinder life
will be dependent on the quality of the water supplied and the length of time the cylinder
will be active.
NOTICE
Following advice received directly from the manufacturers of compressors, we DO
NOT allow the use of additives (for example Quickshot
®
) with ANY Multi-DENCO
system. ANY USE WILL INVALIDATE WARRANTY.
NOTE!
During any service or at any time that the refrigeration system is opened, a replace-
ment filter drier (molecular sieve type) should be fitted. These can contain a propor-
tion of activated oxides that absorb weak acids and remove them from the system.
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