SPC DERV Installation, Operating And Maintenance Instructions page 7

A minimum clearance of 600mm must be ensured on all sides of the unit except the air discharge
side where the clearance must be a minimum of 1500mm.
The unit must be located outside and must not be ducted. Ensure that the unit is not subject to
direct sunlight and cannot be subjected to any water run-off.
The unit must be mounted on a flat horizontal surface where vibrations cannot be transmitted to
the building structure and securely fixed.
A location should be found whereby the length of refrigerant pipes between the outdoor unit and
the indoor DERVDX unit is minimized.
4.3 Refrigerant Piping (DERVDX only)
The detailed instructions regarding the refrigerant piping given in the condensing unit IOM manual
should be followed. The text below gives general guidance. All refrigeration pipework should be
undertaken by a suitably qualified refrigeration engineer.
4.3.1 Liquid/Vapour lines
The table below identifies the recommended liquid and vapour line sizes based on the size of
DERVDX unit being installed. All refrigeration piping should be clean, dehydrated refrigeration
grade copper and should remain sealed until ready for use. A filter drier and liquid sight glass
may be installed in the liquid line upstream of the expansion device.
Unit size Liquid line OD
DERVDX 150 3/8"
DERVDX 250 3/8"
DERVDX 375 3/8"
DERVDX 500 1/2"
Table 2: Recommended refrigerant line sizes.
Both vapour and liquid lines should be insulated to prevent sweating and performance reduction.
A minimum of ½" thick pipe insulation should be used. In order to avoid any reduction in
performance it is recommended that the maximum distance between indoor and outdoor unit
(including any vertical lift) be limited to 15m.
Whenever tubing is cut it should be carefully deburred so as to prevent any chips falling into the
tubing to be used. Any bends in the pipework should be made using proper tube bending
equipment so as to prevent any kinking.
Wherever possible tube connections should be of the sweat type and made using copper brazing
material. For copper to copper brazing up to 5% silver content brazing rods should be used, for
copper to brass or steel then 35% silver content is recommended. Tubing and fittings should be
cleaned with wire wool prior to brazing and any debris prevented from entering the pipe. When
brazing at or near to the service valves the caps and Schraeder cores should be removed to
prevent damage and the valves themselves covered in wet rags. A flow of nitrogen should be
directed through a service port and tubing while brazing.
If flare joints are to be used these must be properly made ensuring the following:
QA/IOM/63 ISSUE 2 - DERV
Vapour line OD
5/8"
7/8"
7/8"
1,1/8"
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