5
Be sure to perform the following before brazing.
The rubber that fastens the tubes is damaged easily by heat. Be sure to remove it before brazing.
Cool the tubes with wet cloths or other materials to prevent the valves inside the machine from being
damaged by the brazing heat.
Be sure to replace the contents of the tube with nitrogen to prevent the formation of an oxide film.
Do not use commercially available oxide film agents (antioxidants). They can adversely affect the
refrigerant and the refrigeration oil, and can cause malfunctions.
If using flare connections (for the indoor connectors or other part), apply refrigeration oil to the flared
part.
3. REFRIGERANT PIPING WORK
1. When working on the piping, keep the pipe lengths short and the height difference between the units small.
Further, make sure the pipes are not crushed when they are being bent.
The lengths of refrigerant pipes and the difference in height between the water heat exchanger unit and the
outdoor unit are shown in Table 1. According to the Table 1, add the
length of refrigerant piping when they are installed. Also add the unit additional charge amount in Table 2
according to the outdoor unit type.
Fig. 4
2. Remove the gas tube and liquid tube fastening rubber.
3. Connect the tubes and perform brazing.
4. Reattach the gas tube, liquid tube fastening rubber as they were originally.
After cutting tube, be sure to remove all burrs and finish tubing ends to the correct
surface. (The same must be done for branch tubes (purchased separately).)
When cutting or bending tubes, be careful not to cause any pinching or blockage of the
tube.
Take care that no water, dirt, or other foreign substance enters the tube.
Table 1 Allowable refrigerant piping length, amount of refrigerant additionally charged, and pipe specifications
Type
Allowable pipe
length
Allowable height difference
When outdoor
unit is higher
When outdoor
unit is lower
50m
* 35m
Amount of additional refrigerant
Refrigerant piping (copper
pipe C1220T, external diam-
eter × wall thickness in mm)
Liquid side
(O-material)
Gas side (1/
2H, H-material)
185g/m
56g/m
For the length of
refrigerant piping
Type 500
Type 250
170m (equivalent
length 200m)
15.88 x 1.0
28.58 x 1.0
259g/m
Type 710
19.05 x 1.0
31.75 x 1.1
9.52 x 0.8
22.22 x 1.0
right amount of refrigerant for the
Fig. 5
CAUTION
Tube connection panel
Liquid tube
(narrow tube)
Gas tube
(wide tube)
Liquid tube
fastening rubber
Gas tube
fastening rubber
Tube connection panel
Liquid tube
fastening rubber
Gas tube
fastening rubber
Liquid tube
(narrow tube)
Gas tube
(wide tube)
Table 2 Unit additional charge amount
Outdoor unit type
Unit additional charge amount
45.0 kW
ʊ
56.0 kW
0.5 kg
71.0 kW
2.5 kg
85.0 kW
10.0 kg
