T9901018-1
Page 24 of 26
Fault Conditions
If the Dry Cooling System does not operate as expected see fault finding table below:
Symptom
Possible Cause
Action Required
Fans in Dry
Cooling Unit
do not
operate
Electrical power is not switched on at
the local electrical isolator next to the
Thermoscreens dry cooling unit
Switch on power to the
Thermoscreens dry cooling
unit
Wire link missing between FAN terminal
and HIGH or MED or LOW terminals
Fit wire link to required speed
(HIGH for specified cooling output)
T8A fuse in dry cooling unit has blown
Replace T8A fuse and
investigate why it has blown
Problem with dry cooling unit motor(s),
or internal wiring, or controls
Use wiring diagram to
investigate possible cause of
fault
Dry Cooling
Unit does not
cool well or
does not cool
at all
Outdoor unit not switched on and/or
(S1, S2 isolator) not switched on
Switch on power to outdoor
unit and (S1, S2 isolator)
Dry cooling heat pump system has
been running for less than 10 minutes
and is still cooling down
Give system sufficient time to
reach operating condition
Remote ON/OFF Control: Dry cooling
unit is set to 'Off'.
Switch Remote ON/OFF to ON
Siemens Manual Room Control: Target
temperature is set too high for cooling
If necessary adjust the Manual
Room Control target
temperature down.
NB. Dry cooling unit will only
cool if room air temperature is
above the target temperature
Room temperature is low - Air Inlet
Sensor is measuring low air
temperature so target temperature has
been exceeded
Water dirt trap device is blocked
Clean water dirt trap device
F2A fuse in dry cooling unit has blown
Replace F2A fuse and
investigate why it has blown
Water pump has failed in water circuit
Repair water pump
Airflow is low
coming from
the discharge
grille
Dry cooling unit air filters and/or cooling
coil is dirty.
Service dry cooling unit as
described in Section –
Servicing on pages 21 to 23
Mitsubishi
Electric
system is
indicating an
error code
A variety of error codes can occur
because of a fault within the heat pump
system. These will display on the
Mitsubishi Electric PAR-W21MAA.
Refer to Mitsubishi Electric
Service Manual to understand
fault, then inspect, adjust
and/or repair as appropriate
Condensate
forming on
the chilled
water coil in
the dry
cooling unit
Failure in the site air conditioning
system
Repair site air conditioning
system
Environmental conditions in the server
room are above 24°C/40%Rh due to
some other circumstance, e.g. doors left
open, extreme weather conditions
Reduce environmental
conditions if possible
Chilled water flow temperature below
10°C
Investigate why water flow
temperature is too low
If the Heat Pump Dry Cooling System is still not operating correctly call for a Mitsubishi
Electric Service Agent.
