Brivis 47
ICE Fixed Speed OIM
6.2 RECOMMENDED INTERCONNECTING PIPE SIZING
Table 3. Recommended Pipe Sizing
Model
Recommended Pipe Size (mm)
For Equivalent Length (m)
Maximum
Equivalent
Pipe
Length(m)
[Minimum Pipe
Length is 3m]
Pre Charge
for 15m
Pipe Length
(kg)
Additional
Charge For
>15m Pipe
Length
(grams/m)
Indoor
Coil Piston
Orifice Size
Liquid
Suction
1-10
10-30
1-10
10-30
DO-SC18Z91
9.52
12.7
22.2
28.6
30
3.60
90
0.084”
DO-SC22Z91
12.7
12.7
28.6
28.6
30
3.71
90
0.074”
NOTE
Both units’ liquid line connection sizes are 12.7mm. For pipe work less than 10m equivalent
length, the DO-SC18Z91 system can be run with 9.52mm liquid line.
Therefore, two 12.7 to 9.52mm copper bushes are included (one with the indoor DI-XU18Z and
one with the DO-SC18Z91 outdoor unit). For pipe work more than 10m equivalent length, a
12.7mm liquid line is needed.
6.3 MAX VERTICAL PIPE RUN
The height difference between indoor and outdoor units must not exceed 8 meters.
If the indoor unit is located more than 5 metres above the outdoor unit, then a solenoid valve should be installed in
the liquid line at the indoor unit, to prevent liquid refrigerant migrating back to the compressor in the off cycle. The
solenoid shall be interlocked with the compressor.
6.4 CORRECTION FACTORS: VAPOUR LINE SIZING VS. COOLING CAPACITY
The total equivalent length of the interconnecting refrigeration lines will affect the cooling capacity of the system.
Table 4 shows the percentage change in cooling capacity versus the equivalent pipe lengths for different suction
line sizes, using the recommended liquid line sizes.
Table 4. Cooling Capacity Correction Factors
Model
Size (mm)
Equivalent Pipe Length (m)
5
7.5
10
15
20
25
30
DO-SC18Z91
Suction line
9.52mm Liquid Line
12.7mm Liquid Line
28.6
1.10%
0.80%
0.50%
0.0%
-0.50%
-0.96%
-1.40%
22.2
0.00%
0.90%
-1.70%
-3.4%
-5.10%
-6.80%
-8.60%
19.1
-2.50%
-4.60%
-6.50%
-10.80%
-15.10%
-19.40%
-23.90%
DO-SC22Z91
Suction line
12.7mm Liquid Line
28.6
0.00%
-0.43%
-0.83%
-1.63%
-2.43%
-3.23%
-4.03%
22.2
-1.83%
-3.23%
-4.63%
-7.23%
-10.03%
-12.83%
-15.63%
6.5 PIPE-WORK CONNECTION
•
Locate the suction & liquid pipe service valves in the compressor compartment by removing the service access
panel
•
Check that the service valves are tightly closed (Service Ball valves have been provided for suction and liquid
lines)
•
Wrap each valve in turn with a wet cloth prior to sweating off its associated blanking plate
•
Braze the interconnecting liquid and suction pipes from the indoor unit
•
Pressurise the indoor unit & pipe-work again with dry nitrogen and check for any brazed joint leaks. Repair as
necessary but ensure the system is not under pressure prior to brazing
•
With the indoor unit pressure again released, evacuate to a vacuum pressure of 100 microns minimum
•
Disconnect the vacuum pump whilst retaining the system vacuum
•
Open the liquid line valve fully first, and then the suction line valve
