Liebert CR020 - Noise Level Specifications; Product Description and Installation Examples

Chapter 1 Preliminary Operations 3
Liebert.CRV Series Air Conditioner User Manual
For air-cooled (A) units
Table 1-4 Operating limits for air-cooled (A) units
Item Description
Outdoor
temperature: lower
limit (-20°C)
To install an air conditioner in places in which external temperature reaches very low values sometime in
the year requires some means of control to maintain adequate condensing pressures to ensure proper
liquid system operation.
With low temperatures the refrigerant condensates in pipeline and the liquid tends to fulfill the
condenser.
It's mandatory to install the following components:
1. Non return valve (liquid line)
Install a non-return valve in the liquid line directly out of the condenser. It doesn’t allow the liquid to come
back to the condenser (that means efficiency loss and dangerous stress for the compressor).
2. Variex fan speed control (the CRV standard outdoor unit has been configured with the function)
Use Variex fan speed control to regulate the condensing pressure and have a continuous and better
subcooling control.
It’s suggested to have:
3. Horizontal condenser position
The condenser horizontal disposition (vertical flow) is necessary to reduce subcooling variations due to
direct wind exposure. (very important to have a good subcooling control).
For all exceptions contact the Emerson sales representative
Outdoor
temperature: higher
limit
This limit is determined by coupled condenser model. Exceeding of this limit (or a lack of maintenance),
will caused a compressor stop by HP safety thermostat. Reset to normal operation can only be carried
out manually.
Once the condensing pressure rises at or above the 34bar / 493psi value, the capacity of the
compressor is reduced by 20% compared to the requested capacity. This because iCOM control tries to
maintain the unit's operability reducing the cooling power of digital scroll
Table 1-5 Relative position of room unit and 50Hz remote condenser
Item Description
From unit to condenser max distance equivalent length
1
50m
From unit to condenser max geodetic height
2
-8m ~ 30m
Requirements
Pipe diameter
See Table 4-2
Oil traps on vertical line of gas refrigerant
Install one every 6m
Extra oil charge
See Table 5 and Table 6 in the appendix
Note:
1: If the equivalent length from the indoor unit to the condenser exceeds 50m, please consult with Emerson sales representative;
2: Positive difference in height: condenser above conditioner; Negative difference in height: condenser below conditioner
For water/glycol-cooled (W) units
Table 1-6 Operating limits for water/glycol-cooled (W) units
Item Description
Water or mixture temperature to condenser Min. 5°C
Other information See Chapter 5 Water Conections
For chilled water (C) and water/glycol-cooled (W) units
Table 1-7 Operating limits for chilled water (C) and water/glycol-cooled (W) units
Item
Description
CR020RW CR035RW CR040RC
Max. water pressure (bar) 16 16 16
Max. differential pressure through the
closed valve: Dpcv (kPa)
300 300 175
Max. differential pressure across the
valve for modulating service: Dpms (kPa)
300 300 175