Vaillant aroTHERM Series, Operating Instructions Manual

Page: 67 / 212

Hydraulics installation 5
0020257297_02 aroTHERM Installation and maintenance instructions
65
5.5 Connecting the refrigerant pipes
5.5.1 Outdoor unit
1
2
1. Apply a drop of flare oil to the outsides of the pipe ends.
2. Connect the hot gas pipe (2) . Tighten the flare nut. Use
pliers to hold the service valve in place while doing so.
Product Pipe diameter Tightening torque
VWL 35/5 and
VWL 55/5 1/2 " 50 to 60 Nm
VWL 75/5 to
VWL 125/5 5/8 " 65 to 75 Nm
3. Connect the liquid pipe (1) . Tighten the flare nut. Use
pliers to hold the service valve in place while doing so.
Product Pipe diameter Tightening torque
VWL 35/5 and
VWL 55/5 1/4 " 15 to 20 Nm
VWL 75/5 to
VWL 125/5 3/8 " 35 to 45 Nm
5.5.2 Indoor unit
▶
Connect the hot gas pipe and the liquid pipe to the indoor
unit (
→
installation instructions, indoor unit).
5.6 Checking the refrigerant circuit for tightness
1. Ensure that the two isolation valves on the outdoor unit
are still closed.
2. Observe the maximum operating pressure in the refri-
gerant circuit. See Technical data (
→
Page 78).
N
2
3 4
1
3. Connect a refrigerant fitting (2) with a ball valve (3) to
the maintenance connection for the hot gas pipe.
4. Connect the refrigerant fitting with a ball valve (1) to a
nitrogen cylinder (4) . Use dry nitrogen.
5. Open both of the ball valves.
6. Open the nitrogen cylinder.
–
Test pressure: 2.5 MPa (25 bar)
7. Close the nitrogen cylinder and the ball valve (1) .
–
Waiting period: 10 minutes
8. Observe whether the pressure is stable. Check all con-
nections in the refrigerant circuit for tightness, partic-
ularly the flare connections from the outdoor unit and
indoor unit. Use leak detection spray for this.
Result 1:
Pressure is stable, and no leaks found:
▶
The test is complete. Completely drain the nitrogen
gas via the refrigerant fitting.
▶
Close the ball valve (3) .
Result 2:
The pressure drops, or a leak is found:
▶
Eliminate the leakage.
▶
Repeat the test.
5.7 Evacuating the refrigerant circuit
Note
During evacuation, residual moisture is removed
from the refrigerant circuit at the same time. The
length of the process depends on the residual
moisture and the outdoor temperature.
1. Ensure that the two isolation valves on the outdoor unit
are still closed.
3
4 5
1
2
2. Connect a refrigerant fitting (3) with a ball valve (4) to
the maintenance connection for the hot gas pipe.
3. Connect the refrigerant fitting with a ball valve (2) to a
vacuum gauge (1) and a vacuum pump (5) .
4. Open both of the ball valves.
5. First test : Switch on the vacuum pump. Drain the refri-
gerant pipes and the indoor unit's plate heat exchanger.
–
Absolute pressure to be reached: 0.1 kPa
(1.0 mbar)
–
Running time of the vacuum pump: 30 minutes
6. Switch off the vacuum pump. Wait three minutes.
Check the pressure.
Result 1:
Pressure is stable:
▶
The first test is complete. Start the second test (step
7).