Johnson Controls York VCH 20A, Technical Information

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- For interconnecting lines of over 25 metres, oil should be
added (30 gr/m. of length).
Layout 1 (Outdoor unit up)
L: Total piping length (ve horizontal sections)
in course and in one only direction.
H: Vertical distance between units.
A: Cooling liquid line.
B: Cooling gas line.
Layout 2 (Indoor unit up)
L: Total piping length (ve horizontal sections)
in course and in one only direction.
H: Vertical distance between units.
A: Cooling liquid line.
B: Cooling gas line.
Pipes to be used
When installing the pipes that join the two units, take special
care in checking that the pipes used are kept clean and dry
prior to installation.
It is advisable to take the following recommendations into
account:
- Use cooling quality copper pipes only (K or L type,
S/ASTMB88).
- Do not work outside when raining.
- The ends of the pipes should remain closed throughout
the installation.
- Do not leave the filter-dryers nor the compressor out in the
open.
- When welding, use low melting point rods. These should
contain 5% silver minimum.
- While welding and as long as the pipe remains hot, maintain
a current of dry nitrogen so as to avoid rust and scaling
inside the pipe. This could cause contamination and ob-
structions.
- Do not use strippers at the copper-copper joints.
- Connection to the units should be carried out by using the
flaring method.
Insulation of refrigerant pipes
Since the interconnecting distribution pipes to the coil are
installed in the outdoor unit, both the larger and the smaller
diameter pipes are on the relative low pressure side of the
system.
Consequently, to avoid condensed water from the pipes
dripping on the floor, both must be insulated with adequate
insulation. The thickness of same should be at least 8 mm.
Draining and drying
Air does not act as refrigerant because it cannot be liquefied
by the compressor.
The air and humidity that remain in the cooling system have
undesirable effects, such as those listed below. Consequently,
they should be eliminated completely.
- High pressure increases.
- Consumed power increases.
- The performance of the unit decreases.
- The water contained in the air can freeze and block the
capillaries.
- Water can cause the corrosion of certain parts of the circuit
and the deterioration of the compressor.
Process
In each circuit:
1- Connect a vacuum pump and a service pressure
gauge.
2- Carry out a vacuum of up to 50 microns, minimum.
3- Check for leaks.
Refrigerant charge
The refrigerant charge is calculated with a pipe length of
7.5 meters.
See the refrigerant charge in the table below, by models
and size.
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