Forum Server Room Air-con Fan Speed Control

The three Forum air-conditioning CCUs are (individually) manually set to run at speeds which we think are suitable to provide the cooling effect we need, whilst minimizing noise and power consumption. Typically, the fans in each CCU will run at something like 35Hz. The lowest selectable speed is 20Hz (the fans' 'idle' speed); the highest selectable speed is 50Hz. (However, note that ACU-02 is currently limited to 45Hz: selecting a higher speed for that CCU produces a warning condition.)

Should the Forum core UPS trigger an alarm in response to temperatures above the high-temperature (currently, 27 deg C), or should ACU-01 completely fail (*), relays will fire with the result that fans in all CCUs will be commanded to run at their highest allowable speed (either 50Hz or 45Hz, depending on the CCU.)

(* The relays are energised by ACU-01 in a failsafe way so that, should ACU-01 electrically fail, all three output relays will fire.)

QUESTION: Does this mean that if ACU-01 is turned off as below, the other two units will always turn full on? Needs to be checked.

To manually alter the running fan speed

On the inverter:

  1. 'Quick Menu'
  2. 'Quick Set-Up' -> OK
  3. Use 'Up' or 'Down' button to select '4-12 Motor Low Speed' -> OK
  4. Input desired speed -> OK
  5. 'Status' to return to main display
  6. Ensure 'Auto' is always selected

To turn off a CCU

Use the big red switch in the middle of the CCU to completely cut the input power.
Press the leftmost button on the 'Carel' control panel and wait: the CCU will do an orderly shutdown, which takes about one minute. Thereafter, use the big red switch in the middle of the CCU to completely cut the input power.

-- IanDurkacz - 23 Jan 2012

Topic revision: r1 - 23 Jan 2012 - 16:47:25 - IanDurkacz
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