Cooling Connections - Carrier 38HB series Installation, Operation And Maintenance Instructions

Split-system cooling units
and heat pumps
Cooling c onne c t ions
Once installed the outdoor and indoor units, the cooling links must be
laid between them
La maximum equivalent length of the cooling line is 30 metres, with a
maximum geometric height of 20 metres when the outdoor unit is high.
The optional available depending on the equivalent equivalent length
between indoor and outdoor unit:
- Medium-distance option (for an equivalent length from 30 to 50
metres): particle separator.
- Long-distance option (for an equivalent length longer than 50 metres):
particle separator + oil separator.
If it is the indoor unit which is high, the maximum equivalent length is
reduced to 7 metres.
It is recommended to place a siphon in the gas line every 3 meters of
shoulder to ease the oil return to the compressor.
Outdoor unit top
Maximum equivalent length of the cooling line: 30 metres
For longer lenghts it is necessary to consult optional
38HB/HF
outdoor
unit
L: liquid line
G: gas line
Siphon in gas line for every
3 metres of drop
40HB/HF
indoor
unit
Outdoor unit bottom
Maximum equivalent length of the cooling line: 7 metres
L: liquid line
G: gas line
Siphon in gas line for every
3 metres of drop
40HB/HF
indoor
unit
For determining the equivalent length, the pressure drops
in accessories must be taken into account.
L G
G L
38HB/HF
outdoor
unit
Pressure drops in elbows expressed as equivalent lengths (m):
Tube installation norms must be
respected and inspect carefully the tube
lay out, looking for the shortest distance
and the lowest possible number of
curves. Also, chokes must be avoided,
using large curve radii (the curve radius
must be ≥ 3,5x
Tube diameter (inches)
Equivalent elbow length 45º (m)
Equivalent elbow length 90º (m)
Equivalent elbow length 180º (m)
Connection of the unit to the cooling lines
For the refrigerant lines, use only cooling type seamless tubes. Under
no circumstance use sanitary type copper pipe.
Following these steps is recommended:
- Revise and clean the tube ends to eliminate the burs from cutting
them and any other impurity that could have deposited inside or on
the outer surface. How clean the tubes are will dictate the degree or
air tightness. Also, we will avoid the dirt formation that may collapse
some spots in the cooling circuit.
- Apply isolator to the piping, covering them and affi x it with tape. The
material used must guarantee the air tightness at operation pressure
and temperature.
- Remove the plugs that protect the cooling connections of the unit
precisely at the moment of connecting the tubes.
- Align precisely both parts of the connection (unit and piping). There
is no error risk when both tubes have different diameters.
- Run a pressure test in the cooling tubes and a search for leaks to
verify the cooling installation.
- Create a vacuum in the installation to eliminate humidity inside the
circuit.
- Charge the unit with gas as per the data stated in the technical
characteristic table. Add the refrigerant slowly via the schrader
valve built into the liquid line, whilst the compressor is in operation,
monitoring the pressures to detect if there are any possible
anomalies.
- If the equivalent length of the cooling lines is over 7 m, an additional
charge will be needed per meter as per the following table.
Nominal diameter (") 1/4" 3/8" 1/2" 5/8" 3/4" 7/8"
Indoor section (cm 2 ) 0,149 0,444 0,900 1,505 2,282 3,120 4,290 5,346
Liquid line charge (g/m) 19,3 57,0 115,0 193,5 292,3 404,1 550,3 685,7
Gas line charge (g/m) -
Note: To ensure that the gas charge is correct, when performing
the "unit operation verifi cation" the subcooling of the liquid must be
checked.
1/2" 5/8" 7/8"
0,24 0,30 0,39
0,45 0,54 0,72
0,75 0,80 1,00
1" 1 1/8"
0,2 0,4 0,7 1,0 1,4 2,0
Æ
1 1/8"
0,48
0,90
1,30
2,5
11