T9901018-1
Page 18 of 26
Carefully slide the Interface PCB back into place if still withdrawn on its slide rails.
Ensure cables are not trapped inside and refit the fixing screw in the left hand end
panel.
Testing the Dry Cooling System
Ensure that the local electrical ON/OFF Switch/Isolator to the Thermoscreens dry
cooling unit is switched OFF !!
Switch on the S1, S2 local isolator adjacent to the Thermoscreens dry cooling unit.
Switch on electrical power to the Mitsubishi Electric Outdoor Unit.
WARNING!
– Terminal S1 and the Mitsubishi Interface PCB inside the dry cooling unit
will now become Live with 230V electrical power from the outdoor unit !!
LED 1 on the Interface PCB should be lit to indicate power onto the PCB. Wait for the
PAR-W21MAA controller at the left hand end of the unit to initialize. The message
‘PLEASE WAIT’ will repeat on the screen of the PAR-W21MAA controller until
communication is set-up and the heat pump system is ready to operate. The PAR-
W21MAA controller will not respond to push button commands because of the dip
switch settings on the Mitsubishi Interface PCB. The outdoor unit
must
now be left
energised for 12 hours before carrying out any further operations.
Now switch on the local electrical ON/OFF Switch/Isolator to the Thermoscreens dry
cooling unit.
WARNING!
– The fans inside of the dry cooling unit will now operate, beware of fast
spinning fans.
WARNING!
– 400V may exist between terminal S1 and other Live terminals inside the
Thermoscreens dry cooling unit.
Check there is no mechanical noise coming from the fans and that both fans work.
If there is a Remote On/Off wired into terminals 6 & 7 on the dry cooling unit, switch this
On. Check that the LCD display screen on the Siemens RDG400 Manual Room Control
is working and lit-up. The display screen will be indicating the room temperature in large
numerals. Rotate the knob on the room control anti-clockwise and the numerals will
change to indicate the target (set-point) temperature. Set this target temperature at least
5°C below the room temperature. The numerals will then flash this target temperature 5
times and go back to showing the air temperature. At this point the water pump(s) will
start to operate and the outdoor unit will also start to work. The display on the PAR-
W21MAA controller will change to show that the outdoor unit is working and LED 3 on
the interface PCB should be lit to indicate the compressor in the outdoor unit is working.
Stop and start the water pump(s) by adjusting the target temperature up and down on
the manual room control to help bleed air out of the chilled water system. Ensure air is
bled out of the pump(s). If a flow setter valve is fitted check that the water flow rate of
the chilled water system is in accordance with Table 1, Page 3 or Table 2, Page 4.
After the system has been operating for a few minutes check that the chilled water
pipework is cooling down and the pipe temperature indicator on the PAR-W21MAA
controller (small numerals) shows a falling temperature. If the system is operating
correctly the pipe temperature should go down to 10°C. Check that cold air is being
discharged from the dry cooling unit across the whole length of the unit and that there is
