Unit installation

CDU Installation Guide Page 21
Cooling Distribution Unit
COMMISSIONING (continued)
5.8 General - Manual Control & Overrides
In Manual Control mode (accessible when logged on at ‘Service’ level), some automatic control functions
can be manually set without affecting the operation of the rest of the unit. This can be done within the
Manual Control screen (screen ref. 4-4), where the following can be set: Speed for Pump 1 or 2 (inverter
operation), On/Off of Pump 1 or 2 (DOL operation), position of Valve 1 or 2 as a percentage open, On/Off
of fill pumps, On/Off of Warning and Alarm extended events (to check the operation of externally
connected alarm circuits).
In addition, the Override mode (only accessible when logged on at Engineer level), allows the operator to
put the unit into ‘dumb’ mode where all outputs need to be manually set. This can be done within the
Override screen (screen ref. 4-3), where the following can be set: Digital outputs, Speed for Pump 1 or 2,
position of Valve 1 or 2. Note: Once the unit is set to a Manual Override state, the unit will shutdown if
previously running in automatic mode.
5.9 Manual Control
After the initial fill process, it is preferable to run the unit in ‘Manual Control’ with a reduced pump
speed to gently circulate the water - enabling any trapped air to vent out through the auto air vents.
To set the unit for manual operation:
Start the unit, then go to the ‘Logon’ screen and enter the ‘Service’ access code as described in
Section 5.3, scroll down to the ‘Service’ menu title (screen ref. 4) and press . Scroll to the ‘Manual
Control’ menu title (screen ref. 4-4) and press . Select ‘Secondary Pumps’ (screen ref. 4-4-1) and
then ‘P1 Inverter’ (screen ref 4-4-1-1) and press . Use the or keys to set the speed to 30%
& press to accept. (Note: If no keys are pressed within a 15 minute time span, the controller will
revert to automatic mode).
While the main pump is running, the fill pumps may switch on again as air is purged from the system.
5.10 Overrides
The unit can also be run in full Override mode (engineer access required), scroll to ‘Overrides’ screen
(screen ref. 4-3) & press . Select ‘Auto/Man mode’ and use the or keys to change display
from ‘Automatic’ to ‘Manual’, press .
Next select the ‘Digital outputs’ menu title (screen ref. 4-3-2) to display the following screen:
OK
OK
OK
OK
room sensor
sec. pressure
prim. pressure
status 3-4
ps1 0.50bar
ps2 0.50bar
dp 0.00bar
Pump inlet pressure
Pump outlet pressure
Pump differential
pressure
sec. pressure
OK
The ‘Status’ & ‘Sec. pressure’ screens
can be used to monitor the secondary
circuit pressure during the system filling
process.
See Section 6.1 for further information
on how to access.
OK
OK