Daikin V3 Technical Manual Download

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T-CU19-JAN24-1

Page 11

Installation Clearances

The installation location should allow sufficient space for air
flow and maintenance around the unit.

Figure 6: Installation Clearance

Field Piping

Pipe sizing should only be determined by
qualified personnel. Correct line sizing will
minimize the pressure drop and maintain
sufficient gas velocity for proper oil return.

All applicable standards must be observed in the
installation of refrigerant piping.

To ensure satisfactory operation and performance, the
following points should be noted:

•

Pipework routes must be as simple and as short as
possible.

•

Avoid low points on pipework where oil can
accumulate.

•

Suction gas velocity must be sufficient to ensure good
oil return.

•

Use only clean, dehydrated refrigeration grade
copper tube with long radius bends.

•

Avoid flare type connections and take great care when
brazing. Use brazing filler alloys containing phosphorus
such as BCuP-7 without flux for joining copper tubes.

•

Dissimilar metals such as copper and brass shall be
joined using an appropriate flux with high silver
content filler material such as BAg-34. Apply flux
sparingly to the clean tube only and in a manner to
avoid leaving any excess inside of completed joints.

•

Run braze without over filling to ensure there is no
leakage into the tube.

•

To prevent oxidation, blow oxygen free nitrogen
through pipework when brazing.

•

Install insulation on all suction lines and on all pipes
penetrating walls or passing through hot areas.

•

Adequately support all pipework at a maximum of 2m
intervals.

•

Where the condensing unit is situated below the indoor
unit (coldroom evaporator / display case), the height
difference between the two units should be no more
than 6 meters.

•

In vertical pipework, the use of U-trap and double
suction risers is often required. These suction risers must
always be fitted with a U-trap at the bottom and a P-
trap at the top and never be higher than 4m unless a
second U-trap system is fitted.

•

Additional oil may be required if piping length
exceeds 20m or multiple oil traps are fitted. Check the

oil level closely during commissioning and add oil as
necessary. Add oil in small amounts. Do not overfill the
compressor!

•

Suction pipework should slope gently back towards the
unit to assist oil return to the compressor. A fall of
approximately 2cm per meter of pipework is
acceptable.

•

Liquid lines should be sized to ensure a full supply of
liquid refrigerant to the expansion device. Careful
attention should be paid to sizing of liquid lines on
large risers (maximum rise 6m).

•

In some circumstances, a suction accumulator (not
supplied) may be required. It offers protection against
refrigerant flood back during operation and against
off-cycle migration by adding internal free volume to
the low side of the system.

•

Tests must be conducted to ensure the amount of off-
cycle migration to the compressor does not exceed the

compressor’s charge limit

of 6kgs.

•

All evaporators must have their own thermostat/liquid
line solenoid valve.

•

The maximum recommended pipe length is 25m from
the closest indoors.

•

It is recommended to install Pressure Relief Valve on
the liquid receiver if there is a risk of fire incidence.
Increasing temperature will lead to pressure increase in
receiver.

•

No valves and detachable joints shall be in areas
accessible to the public except when they comply with
EN 16084.

•

Field piping for outdoor unit located below indoor unit:
Inverted P-trap is necessary (

Figure 8

). To prevent

refrigerant from draining into the compressor during
off-cycle.

One of the main factors affecting equipment
reliability and compressor service life is
refrigeration circuit contamination.

During installation, circuit contamination can be caused by:

•

Brazing & Welding Oxides

•