Multi-DENCO Fault Finding and Troubleshooting
FläktGroup DC-2013-0101-GB • Subject to modifications • R5-08/2020 125
Fault Possible Reason Possible Remedy
Low pressure in refrigeration sys-
tem (low pressure alarm)
Possible leak in pipework Investigate location of leak and repair. Once repair perform
pressure tests and re-commission
High pressure in refrigeration
system
Too much refrigerant within
system
Refer to commissioning report and compare current condi-
tions with conditions during commissioning. If significant
changes then perform re-commission the unit.
Outdoor fans or water pump may
not be operating
See ‘Fault’ below
Fuse or relay fault
Review the unit to check for damage to any fuse or relay that
is part of the refrigeration circuit operation
Outdoor heat exchanger is
blocked/dirty
Clean heat exchanger fins and clear debris in and around
unit
Insufficient water-cooling (W-Ver-
sion & P-Version)
For P-Version; see ‘Pump failure’ and see ‘Outdoor fans not
operating’
Otherwise check for waterflow and sample water tempera-
tures against design. Alternative, check heat exchanger
does not have any fouling and perform “backflush” as nec-
essary.
Indoor fans not operating Blocked filter alarm
Check the coil filters for cleanliness, clean or replace as ap-
propriate
Fan motor failure
The fan and the motor are a dynamic pair, therefore the fan
assembly must be replaced
Fan relay not activating
Check the fan relays (1 relay per fan)
Unit off by…
Check the controller display to see if the unit has been dis-
abled by; BMS, Time or Keyboard. If the unit is also part of
a network, it could be on a ‘Stand-by’ status.
Outdoor fans not operating Outdoor unit isolated
Check the isolator on the unit is set to the ON position
Condensing pressures below
the minimum requirements
If the refrigerant circuit pressure is below the condenser’s
set-point the fans will not activate – observe the pressure in-
creasing in the unit controller and check fans start when
pressure increases sufficiently
Outdoor unit not receiving con-
trol signal
Check cable integrity and signal at terminals and source
(indoor unit for DMOUCD, outdoor unit controller for
DMOUDW).
Unit not cooling / heating / humid-
ifying / dehumidifying
Pump failure (F-Version & P-Ver-
sion only)
Check for water flow through the pump circuit. Otherwise
check electrical contacts and operation.
No image on the display No power to the unit
Check the power supply at the mains power distribution
board and at the local isolator.
Display unit cable disconnected
Deactivate the unit and open the door with the display. In-
spect the connection and cable at the display and the con-
troller.
Tab. 11-1
To Next Page
Loading...
