Chapter 9 Calibrations & Regulation (At Start-Up) 39
Liebert.CRV Series Air Conditioner User Manual
Chapter 9 Calibrations & Regulation (At Start-Up)
The air conditioner has already been tested and calibrated in factory, but it is very important to check, at start-up, the
superheating of thermostatic valve (A/W versions).
The air conditioner has already been tested in factory.
For calibrations of instruments installed on the external condensers/dry coolers refer to the relevant manual.
For control system calibrations refer to Control manual (to prevent erratic operations do not use temperature and
rel. humidity set points/proportional bands which differ excessively from the standard settings).
9.1 Setting Thermostatic Expansion Valve
This operation must be performed by an experienced refrigeration technician.
The valve has been factory preset and, if necessary, should be reset as follows:
1. Important: ensure that the instructions in Chapter 4 have been carried out.
2. Allow the compressor to operate for 15 minutes.
3. Measure the superheat as follows:
1) Place a contact thermometer on the tube exiting the evaporator.
2) Connect a manometer to the compressor suction valve.
3) The overheating is the difference between the refrigerant saturation temperature corresponding to the pressure
read on the manometer and the real temperature read on the thermometer.
4. The superheat must be 5K ~ 8K; if not, set the expansion valve as follows:
1) Remove the protective cover.
2) Turn the adjustment screw by 1/4 turn only.
3) Wait 10 minutes.
4) Measure the superheat and repeat the operation if necessary.
Note: If the superheat is too low, the screw must be turned in a clockwise direction. If the superheat is too high, the
screw must be turned in a counterclockwise direction.
9.2 Water Leakage Sensor
Due to high flooding alarm device sensitivity, to the end to avoid undesirable alarm signal because of few sporadic
water drops, place the sensors at a minimum distance of 50cm from the unit base perimeter.
This solution assures alarm intervention for real flooding risk only.
9.3 Environment Protection
A misuse or an incorrect calibration of the unit leads to increased energy consumption, resulting in an economic and
environmental damage.
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