Unit installation

CDU Installation Guide Page 23
Cooling Distribution Unit
COMMISSIONING (continued)
To adjust the primary flow rate:
Set the controller to ‘Manual Control’ as described in Section 5.9 and adjust Valve 1 (screen ref. 4-4-2-1
under ‘Heat Exchanger’) to 100%, this will force Valve 1 to open fully. Next go back to the ‘Status’ mode of
the controller and scroll to the ‘Primary Flow’ screen (screen ref. 3-8) to see the actual primary flow rate.
Use the primary return ball valve (see Fig. 4) to approximately regulate the flow to the required setting.
Then use the primary by-pass valve shown in Fig. 7 to give a finer adjustment of the flow. Set Valve 1
setting back to 0% and set controller mode back to ‘Automatic’ operation.
5.13 Secondary Flow Balancing Valves (optional - as part of internal manifold only)
The secondary supply manifold is fitted with an automatic flow control balancing valve for each circuit.
These valves ensure that each circuit always receives the correct flow even if each circuit has a different
pressure drop (e.g. due to longer supply/return hose length). The valves are supplied pre-set to 2400L/H
(40L/M – 10.6USgpm), but are adjustable from 640L/H to 3200L/H (10.7L/M to 53.3L/M – 2.82USgpm to
14.1USgpm).The valves are set as a percentage of full flow, therefore for adjustment of valves to 2400L/H
(10.6USgpm):
Valve setting = x 100 = 75%
The valves (see item 26 on page 49) are fitted
with a blue plastic cap, which if wound clockwise
will close the valve completely. When the cap is
fully unwound anti-clockwise until ‘loose’, the
valve will control to its pre-setting and this will be
the normal operating position for connected
circuits.
To adjust the valve, first remove the blue plastic
cap, as shown to the right (Note: Only do this
when the cap is fully unscrewed and free turning,
to avoid damage). Raise the grey plastic ring and
turn so that the red mark lines up with the new
setting, then release the ring and replace the blue
plastic cap (Note when replacing the cap, the
arrow markings on the grey section should align
with the flats on the threaded section of the brass
valve body).
2400
3200
Fig. 7 - Primary By-pass Valve
By-pass Valve Location