Air Ducts (Indoor Unit) - York SAC Technical Manual

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Air ducts (indoor unit)

1.- Connect the ducts, isolating from the unit by means of a
flexible hose, preferably of a non-combustible material, so
as to avoid transmitting the vibration of the unit itself. If the
ducts are made of flexible material they do not transmit
vibrations.
2.- It is advisable to place a damper at each discharge duct
derivation so as to be able to carry out a correct balance
of the system.
3.- Make sure there is easy access for cleaning and changing
the air filters.
Drainage connections
Install the drainage tubing of each tray through a siphon.
Leave a minimum height difference of 75 mm. between the
height of the connection to the unit and the line after the
siphon (see figure). This is to avoid that the pressure drop
produced by the fan may not interfere with the emptying of the
tray. There should be an access so that, at the beginning of
each season, the siphon may be filled with water. The
drainage line should have a minimum inclination of 2 cms. per
meter of total length.
SLOPE
2%
Valves and refrigerant load
The SOC-076 unit has only one circuit and is supplied with
two valves. The SOC-150 unit has two circuits and is
supplied with four valves. These valves are supplied closed
and with an entire refrigerant load in the outdoor unit (pump-
down). Before starting the unit, make sure the valves are
completely open. The SOC-090 and SOC-120 units have
only one circuit while the SOC-180 and SOC-240 units
have two circuits. These units are suppied without valves, but
with connections ready for welding. The refrigerant load must
be carried out completely on site. See refrigerant load in the
corresponding section, and follow the recommendations
made in the Refrigerant Interconnections and Refrigerant
Load Process sections.
Emptying and dehydrating
Air does not act as a refrigerant as it cannot be liquified by the
compressor. The air and humidity remaining in the cooling
10
system should be completely eliminated, as these have
undesirable effects, as indicated in the list below.
- High pressure increase.
- Power consumption increase.
- Equipment performance decrease.
- The water contained in the air may freeze and block the
capillaries.
- The water may corrode certain parts of the circuit and
deteriorate the compressor.
Emptying and dehydration should be carried out by means of
a vacuum pump.
The vacuum needed is 200 microns (0.2 mm. Hg.).
Connection of the vacuum pump to the cooling circuit should
be made at the 1/4" SAE connections furnished for this
purpose, and with the valves closed.
This will allow emptying and dehydrating the units and
interconnecting tubing.
The SOC-076 and SOC-150 units are supplied preloaded
with refrigerant and does not need to be emptied.
Leakage detection
Leakage detection in the circuit that joins the two units will be
carried out by using R-22 refrigerant and the aid of a detector.
Refrigerant load
The nominal refrigerant load is calculated for a tubing length
of 7.5 meters.
Model
SOC-076/SIC-076
SOC-090/SIC-090/120
SOC-120/SIC-090/120
PLUG
SOC-150/SIC-150
SOC-180/SIC-180
SOC-240/SIC-240
Adjusting the refrigerant load
For lengths of tubing of over or under 7.5 m., the nominal
refrigerant load should be increased or decreased by the
grammes indicated above, in accordance to as to whether the
length of the liquid tubing has been increased or decreased.
Refrigerant interconnections
When installing the tubing that interconnect both units, take
special care in keeping the tubing to be used clean and dry
prior to installation. The following recommendations are
advisable:
1- Use only refrigerant quality copper tubing.
2- Do not work outdoors in the rain.
3- The ends of the tubing should remain closed during
installation.
4- Do not leave neither the drying filters nor the compressor
out in the open for more than one or two minutes.
5- For welding use low-solidus point rods with a minimum 5%
silver content.
6- When welding, and while the tubing is still hot, a flow of dry
nitrogen should be maintained so as to avoid the forming
of oxides and scales in the interior which could cause
Nominal Number Diameter
load of liquid
R-22 kg circuits line
7.1 1 1/2" (12.7 mm)
9.4 1 5/8" (15.87 mm)
11.45 1 5/8" (15.87 mm)
7 2 1/2" (12.7 mm)
9 2 5/8" (15.87 mm)
11.5 2 5/8" (15.87 mm)
Additional
load
grs. (per
meter)
104
170
170
104
170
170